contains 250 rules |
System Settings
[ref]groupContains rules that check correct system settings. |
contains 180 rules |
Installing and Maintaining Software
[ref]groupThe following sections contain information on
security-relevant choices during the initial operating system
installation process and the setup of software
updates. |
contains 24 rules |
System and Software Integrity
[ref]groupSystem and software integrity can be gained by installing antivirus, increasing
system encryption strength with FIPS, verifying installed software, enabling SELinux,
installing an Intrusion Prevention System, etc. However, installing or enabling integrity
checking tools cannot prevent intrusions, but they can detect that an intrusion
may have occurred. Requirements for integrity checking may be highly dependent on
the environment in which the system will be used. Snapshot-based approaches such
as AIDE may induce considerable overhead in the presence of frequent software updates. |
contains 8 rules |
Software Integrity Checking
[ref]groupBoth the AIDE (Advanced Intrusion Detection Environment)
software and the RPM package management system provide
mechanisms for verifying the integrity of installed software.
AIDE uses snapshots of file metadata (such as hashes) and compares these
to current system files in order to detect changes.
The RPM package management system can conduct integrity
checks by comparing information in its metadata database with
files installed on the system. |
contains 6 rules |
Verify Integrity with RPM
[ref]groupThe RPM package management system includes the ability
to verify the integrity of installed packages by comparing the
installed files with information about the files taken from the
package metadata stored in the RPM database. Although an attacker
could corrupt the RPM database (analogous to attacking the AIDE
database as described above), this check can still reveal
modification of important files. To list which files on the system differ from what is expected by the RPM database:
$ rpm -qVa
See the man page for rpm to see a complete explanation of each column. |
contains 3 rules |
Verify File Hashes with RPM
[ref]ruleWithout cryptographic integrity protections, system
executables and files can be altered by unauthorized users without
detection.
The RPM package management system can check the hashes of
installed software packages, including many that are important to system
security.
To verify that the cryptographic hash of system files and commands matches vendor
values, run the following command to list which files on the system
have hashes that differ from what is expected by the RPM database:
$ rpm -Va --noconfig | grep '^..5'
A "c" in the second column indicates that a file is a configuration file, which
may appropriately be expected to change. If the file was not expected to
change, investigate the cause of the change using audit logs or other means.
The package can then be reinstalled to restore the file.
Run the following command to determine which package owns the file:
$ rpm -qf FILENAME
The package can be reinstalled from a zypper repository using the command:
$ sudo zypper reinstall PACKAGENAME
Alternatively, the package can be reinstalled from trusted media using the command:
$ sudo rpm -Uvh PACKAGENAME Rationale:The hashes of important files like system executables should match the
information given by the RPM database. Executables with erroneous hashes could
be a sign of nefarious activity on the system. Identifiers:
CCE-85788-8 References:
11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.3.8, 3.4.1, CCI-000366, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3), PR.DS-6, PR.DS-8, PR.IP-1, Req-11.5, 11.5.2, SRG-OS-000480-GPOS-00227 Remediation Ansible snippet: (show)
Complexity: | high |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: 'Set fact: Package manager reinstall command (dnf)'
set_fact:
package_manager_reinstall_cmd: dnf reinstall -y
when: ansible_distribution == "Fedora"
tags:
- CCE-85788-8
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_hashes
- name: 'Set fact: Package manager reinstall command (yum)'
set_fact:
package_manager_reinstall_cmd: yum reinstall -y
when: (ansible_distribution == "RedHat" or ansible_distribution == "CentOS" or ansible_distribution
== "OracleLinux")
tags:
- CCE-85788-8
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_hashes
- name: 'Set fact: Package manager reinstall command (zypper)'
set_fact:
package_manager_reinstall_cmd: zypper in -f -y
when: ansible_distribution == "SLES"
tags:
- CCE-85788-8
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_hashes
- name: Read files with incorrect hash
command: rpm -Va --nodeps --nosize --nomtime --nordev --nocaps --nolinkto --nouser
--nogroup --nomode --noghost --noconfig
register: files_with_incorrect_hash
changed_when: false
failed_when: files_with_incorrect_hash.rc > 1
check_mode: false
when: (package_manager_reinstall_cmd is defined)
tags:
- CCE-85788-8
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_hashes
- name: Create list of packages
command: rpm -qf "{{ item }}"
with_items: '{{ files_with_incorrect_hash.stdout_lines | map(''regex_findall'',
''^[.]+[5]+.* (\/.*)'', ''\1'') | map(''join'') | select(''match'', ''(\/.*)'')
| list | unique }}'
register: list_of_packages
changed_when: false
check_mode: false
when:
- files_with_incorrect_hash.stdout_lines is defined
- (files_with_incorrect_hash.stdout_lines | length > 0)
tags:
- CCE-85788-8
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_hashes
- name: Reinstall packages of files with incorrect hash
command: '{{ package_manager_reinstall_cmd }} ''{{ item }}'''
with_items: '{{ list_of_packages.results | map(attribute=''stdout_lines'') | list
| unique }}'
when:
- files_with_incorrect_hash.stdout_lines is defined
- (package_manager_reinstall_cmd is defined and (files_with_incorrect_hash.stdout_lines
| length > 0))
tags:
- CCE-85788-8
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_hashes
Remediation Shell script: (show)
# Find which files have incorrect hash (not in /etc, because of the system related config files) and then get files names
files_with_incorrect_hash="$(rpm -Va --noconfig | grep -E '^..5' | awk '{print $NF}' )"
# From files names get package names and change newline to space, because rpm writes each package to new line
packages_to_reinstall="$(rpm -qf $files_with_incorrect_hash | tr '\n' ' ')"
zypper install -f -y $packages_to_reinstall
|
Verify and Correct Ownership with RPM
[ref]ruleThe RPM package management system can check file ownership
permissions of installed software packages, including many that are
important to system security. After locating a file with incorrect
permissions, which can be found with
rpm -Va | awk '{ if (substr($0,6,1)=="U" || substr($0,7,1)=="G") print $NF }'
run the following command to determine which package owns it:
$ rpm -qf FILENAME
Next, run the following command to reset its permissions to
the correct values:
$ sudo rpm --setugids PACKAGENAME Warning:
Profiles may require that specific files be owned by root while the default owner defined
by the vendor is different.
Such files will be reported as a finding and need to be evaluated according to your policy
and deployment environment. Rationale:Ownership of binaries and configuration files that is incorrect
could allow an unauthorized user to gain privileges that they should
not have. The ownership set by the vendor should be maintained. Any
deviations from this baseline should be investigated. Identifiers:
CCE-91290-7 References:
1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9, 5.10.4.1, APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.04, DSS05.07, DSS06.02, MEA02.01, 3.3.8, 3.4.1, CCI-001494, CCI-001496, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R4.2, CIP-003-8 R6, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3), PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1, Req-11.5, 11.5.2, SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000278-GPOS-00108, 6.1.1 |
Verify and Correct File Permissions with RPM
[ref]ruleThe RPM package management system can check file access permissions
of installed software packages, including many that are important
to system security.
Verify that the file permissions of system files
and commands match vendor values. Check the file permissions
with the following command:
$ sudo rpm -Va | awk '{ if (substr($0,2,1)=="M") print $NF }'
Output indicates files that do not match vendor defaults.
After locating a file with incorrect permissions,
run the following command to determine which package owns it:
$ rpm -qf FILENAME
Next, run the following command to reset its permissions to
the correct values:
$ sudo rpm --setperms PACKAGENAME Warning:
Profiles may require that specific files have stricter file permissions than defined by the
vendor.
Such files will be reported as a finding and need to be evaluated according to your policy
and deployment environment. Rationale:Permissions on system binaries and configuration files that are too generous
could allow an unauthorized user to gain privileges that they should not have.
The permissions set by the vendor should be maintained. Any deviations from
this baseline should be investigated. Identifiers:
CCE-85782-1 References:
1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9, 5.10.4.1, APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.04, DSS05.07, DSS06.02, MEA02.01, 3.3.8, 3.4.1, CCI-001493, CCI-001494, CCI-001495, CCI-001496, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R4.2, CIP-003-8 R6, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3), CM-6(a), PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1, Req-11.5, 11.5.2, SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099, SRG-OS-000278-GPOS-00108, 6.1.1 Remediation Ansible snippet: (show)
Complexity: | high |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Read list of files with incorrect permissions
command: rpm -Va --nodeps --nosignature --nofiledigest --nosize --nomtime --nordev
--nocaps --nolinkto --nouser --nogroup
register: files_with_incorrect_permissions
failed_when: files_with_incorrect_permissions.rc > 1
changed_when: false
check_mode: false
tags:
- CCE-85782-1
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_permissions
- name: Create list of packages
command: rpm -qf "{{ item }}"
with_items: '{{ files_with_incorrect_permissions.stdout_lines | map(''regex_findall'',
''^[.]+[M]+.* (\/.*)'', ''\1'') | map(''join'') | select(''match'', ''(\/.*)'')
| list | unique }}'
register: list_of_packages
changed_when: false
check_mode: false
when: (files_with_incorrect_permissions.stdout_lines | length > 0)
tags:
- CCE-85782-1
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_permissions
- name: Correct file permissions with RPM
command: rpm --setperms '{{ item }}'
with_items: '{{ list_of_packages.results | map(attribute=''stdout_lines'') | list
| unique }}'
when: (files_with_incorrect_permissions.stdout_lines | length > 0)
tags:
- CCE-85782-1
- CJIS-5.10.4.1
- NIST-800-171-3.3.8
- NIST-800-171-3.4.1
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(c)
- NIST-800-53-CM-6(d)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- NIST-800-53-SI-7(6)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- high_complexity
- high_severity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- rpm_verify_permissions
Remediation Shell script: (show)
Complexity: | high |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Declare array to hold set of RPM packages we need to correct permissions for
declare -A SETPERMS_RPM_DICT
# Create a list of files on the system having permissions different from what
# is expected by the RPM database
readarray -t FILES_WITH_INCORRECT_PERMS < <(rpm -Va --nofiledigest | awk '{ if (substr($0,2,1)=="M") print $NF }')
for FILE_PATH in "${FILES_WITH_INCORRECT_PERMS[@]}"
do
# NOTE: some files maybe controlled by more then one package
readarray -t RPM_PACKAGES < <(rpm -qf "${FILE_PATH}")
for RPM_PACKAGE in "${RPM_PACKAGES[@]}"
do
# Use an associative array to store packages as it's keys, not having to care about duplicates.
SETPERMS_RPM_DICT["$RPM_PACKAGE"]=1
done
done
# For each of the RPM packages left in the list -- reset its permissions to the
# correct values
for RPM_PACKAGE in "${!SETPERMS_RPM_DICT[@]}"
do
rpm --restore "${RPM_PACKAGE}"
done
|
Verify Integrity with AIDE
[ref]groupAIDE conducts integrity checks by comparing information about
files with previously-gathered information. Ideally, the AIDE database is
created immediately after initial system configuration, and then again after any
software update. AIDE is highly configurable, with further configuration
information located in /usr/share/doc/aide-VERSION . |
contains 3 rules |
Install AIDE
[ref]ruleThe aide package can be installed with the following command:
$ sudo zypper install aide Rationale:The AIDE package must be installed if it is to be available for integrity checking. Identifiers:
CCE-83289-9 References:
BP28(R51), 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9, 5.10.1.3, APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06, CCI-002696, CCI-002699, CCI-001744, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6, 1034, 1288, 1341, 1417, A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3, CM-6(a), DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3, Req-11.5, 11.5.2, SRG-OS-000445-GPOS-00199, SLES-15-010419, 1.4.1, SV-255922r880967_rule Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_aide
class install_aide {
package { 'aide':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "aide"
version = "*"
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure aide is installed
package:
name: aide
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83289-9
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010419
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_aide_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "aide"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Build and Test AIDE Database
[ref]ruleRun the following command to generate a new database:
$ sudo /usr/bin/aide --init
By default, the database will be written to the file
/var/lib/aide/aide.db.new .
Storing the database, the configuration file /etc/aide.conf , and the binary
/usr/bin/aide
(or hashes of these files), in a secure location (such as on read-only media) provides additional assurance about their integrity.
The newly-generated database can be installed as follows:
$ sudo cp /var/lib/aide/aide.db.new /var/lib/aide/aide.db
To initiate a manual check, run the following command:
$ sudo /usr/bin/aide --check
If this check produces any unexpected output, investigate.Rationale:For AIDE to be effective, an initial database of "known-good" information about files
must be captured and it should be able to be verified against the installed files. Identifiers:
CCE-85787-0 References:
BP28(R51), 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9, 5.10.1.3, APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3, CM-6(a), DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3, Req-11.5, 11.5.2, SRG-OS-000445-GPOS-00199, SLES-15-010419, 1.4.1, SV-255922r880967_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Build and Test AIDE Database - Ensure Repositories Are Updated
ansible.builtin.command: zypper -q --no-remote ref
ignore_errors: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85787-0
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010419
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_build_database
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Build and Test AIDE Database - Ensure AIDE Is Installed
ansible.builtin.package:
name: '{{ item }}'
state: present
with_items:
- aide
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85787-0
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010419
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_build_database
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Build and Test AIDE Database - Build and Test AIDE Database
ansible.builtin.command: /usr/bin/aide --init
changed_when: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85787-0
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010419
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_build_database
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Build and Test AIDE Database - Check Whether the Stock AIDE Database Exists
ansible.builtin.stat:
path: /var/lib/aide/aide.db.new
register: aide_database_stat
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85787-0
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010419
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_build_database
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Build and Test AIDE Database - Stage AIDE Database
ansible.builtin.copy:
src: /var/lib/aide/aide.db.new
dest: /var/lib/aide/aide.db
backup: true
remote_src: true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (aide_database_stat.stat.exists is defined and aide_database_stat.stat.exists)
tags:
- CCE-85787-0
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010419
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_build_database
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper -q --no-remote ref
zypper install -y "aide"
/usr/bin/aide --init
/bin/cp -p /var/lib/aide/aide.db.new /var/lib/aide/aide.db
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Configure Systemd Timer Execution of AIDE
[ref]ruleAt a minimum, AIDE should be configured to run a weekly scan.
To implement a systemd service and a timer unit to run the service periodically:
For example, if a systemd timer is expected to be started every day at 5AM
OnCalendar=*-*-* 05:00:0 [Timer] section in the timer unit and
a Unit section starting the AIDE check service unit should be referred.Rationale:AIDE provides a means to check if unauthorized changes are made to the system.
AIDE itself does not setup a periodic execution, so in order to detect unauthorized
changes a systemd service to run the check and a systemd timer to take care
of periodical execution of that systemd service should be defined. Identifiers:
CCE-92516-4 References:
BP28(R51), 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9, 5.10.1.3, APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06, CCI-001744, CCI-002699, CCI-002702, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3, SI-6(d), DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3, Req-11.5, 11.5.2, SRG-OS-000363-GPOS-00150, SRG-OS-000446-GPOS-00200, SRG-OS-000447-GPOS-00201, SLES-15-010570, 1.4.2, SV-234864r902854_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-92516-4
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010570
- NIST-800-53-SI-6(d)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_periodic_checking_systemd_timer
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Configure Systemd Timer Execution of AIDE - Define AIDE Periodic Check Service
ansible.builtin.blockinfile:
create: true
dest: /etc/systemd/system/aidecheck.service
owner: root
group: root
mode: '0644'
block: |
[Unit]
Description=Aide Check
[Service]
Type=simple
ExecStart=/usr/sbin/aide --check
[Install]
WantedBy=multi-user.target
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"aide" in ansible_facts.packages'
tags:
- CCE-92516-4
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010570
- NIST-800-53-SI-6(d)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_periodic_checking_systemd_timer
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Configure Systemd Timer Execution of AIDE - Define AIDE Periodic Check Service
Timer
ansible.builtin.blockinfile:
create: true
dest: /etc/systemd/system/aidecheck.timer
owner: root
group: root
mode: '0644'
block: |
[Unit]
Description=Aide check every day at 5AM
[Timer]
OnCalendar=*-*-* 05:00:00
Unit=aidecheck.service
[Install]
WantedBy=multi-user.target
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"aide" in ansible_facts.packages'
tags:
- CCE-92516-4
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010570
- NIST-800-53-SI-6(d)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_periodic_checking_systemd_timer
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Configure Systemd Timer Execution of AIDE - Ensure AIDE Service is Enabled
ansible.builtin.systemd:
name: aidecheck.service
enabled: true
daemon_reload: true
masked: false
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"aide" in ansible_facts.packages'
tags:
- CCE-92516-4
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010570
- NIST-800-53-SI-6(d)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_periodic_checking_systemd_timer
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Configure Systemd Timer Execution of AIDE - Ensure AIDE Service Timer is Enabled
ansible.builtin.systemd:
name: aidecheck.timer
state: started
enabled: true
daemon_reload: true
masked: false
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"aide" in ansible_facts.packages'
tags:
- CCE-92516-4
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010570
- NIST-800-53-SI-6(d)
- PCI-DSS-Req-11.5
- PCI-DSSv4-11.5.2
- aide_periodic_checking_systemd_timer
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q aide; }; then
zypper install -y "aide"
# create unit file for periodic aide database check
cat > /etc/systemd/system/aidecheck.service <<EOF
[Unit]
Description=Aide Check
[Service]
Type=simple
ExecStart=/usr/sbin/aide --check
[Install]
WantedBy=multi-user.target
EOF
# create unit file for the aide check timer
cat > /etc/systemd/system/aidecheck.timer <<EOF
[Unit]
Description=Aide check every day at 5AM
[Timer]
OnCalendar=*-*-* 05:00:00
Unit=aidecheck.service
[Install]
WantedBy=multi-user.target
EOF
# setup service unit files attributes
chown root:root /etc/systemd/system/aidecheck.*
chmod 0644 /etc/systemd/system/aidecheck.*
# enable the aide related services
systemctl daemon-reload
systemctl enable aidecheck.service
systemctl --now enable aidecheck.timer
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
System Cryptographic Policies
[ref]groupLinux has the capability to centrally configure cryptographic polices. The command
update-crypto-policies is used to set the policy applicable for the various
cryptographic back-ends, such as SSL/TLS libraries. The configured cryptographic
policies will be the default policy used by these backends unless the application
user configures them otherwise. When the system has been configured to use the
centralized cryptographic policies, the administrator is assured that any application
that utilizes the supported backends will follow a policy that adheres to the
configured profile.
Currently the supported backends are:
- GnuTLS library
- OpenSSL library
- NSS library
- OpenJDK
- Libkrb5
- BIND
- OpenSSH
Applications and languages which rely on any of these backends will follow the
system policies as well. Examples are apache httpd, nginx, php, and others. |
contains 2 rules |
Configure System Cryptography Policy
[ref]ruleTo configure the system cryptography policy to use ciphers only from the DEFAULT
policy, run the following command:
$ sudo update-crypto-policies --set DEFAULT
The rule checks if settings for selected crypto policy are configured as expected. Configuration files in the /etc/crypto-policies/back-ends are either symlinks to correct files provided by Crypto-policies package or they are regular files in case crypto policy customizations are applied.
Crypto policies may be customized by crypto policy modules, in which case it is delimited from the base policy using a colon.Warning:
The system needs to be rebooted for these changes to take effect. Warning:
System Crypto Modules must be provided by a vendor that undergoes
FIPS-140 certifications.
FIPS-140 is applicable to all Federal agencies that use
cryptographic-based security systems to protect sensitive information
in computer and telecommunication systems (including voice systems) as
defined in Section 5131 of the Information Technology Management Reform
Act of 1996, Public Law 104-106. This standard shall be used in
designing and implementing cryptographic modules that Federal
departments and agencies operate or are operated for them under
contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf
To meet this, the system has to have cryptographic software provided by
a vendor that has undergone this certification. This means providing
documentation, test results, design information, and independent third
party review by an accredited lab. While open source software is
capable of meeting this, it does not meet FIPS-140 unless the vendor
submits to this process. Rationale:Centralized cryptographic policies simplify applying secure ciphers across an operating system and
the applications that run on that operating system. Use of weak or untested encryption algorithms
undermines the purposes of utilizing encryption to protect data. Identifiers:
CCE-85776-3 References:
164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.312(e)(1), 164.312(e)(2)(ii), 1446, CIP-003-8 R4.2, CIP-007-3 R5.1, CIP-007-3 R7.1, AC-17(a), AC-17(2), CM-6(a), MA-4(6), SC-13, SC-12(2), SC-12(3), FCS_COP.1(1), FCS_COP.1(2), FCS_COP.1(3), FCS_COP.1(4), FCS_CKM.1, FCS_CKM.2, FCS_TLSC_EXT.1, 2.2.7, SRG-OS-000396-GPOS-00176, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_system_crypto_policy # promote to variable
set_fact:
var_system_crypto_policy: !!str DEFAULT
tags:
- always
- name: Configure System Cryptography Policy
lineinfile:
path: /etc/crypto-policies/config
regexp: ^(?!#)(\S+)$
line: '{{ var_system_crypto_policy }}'
create: true
tags:
- CCE-85776-3
- NIST-800-53-AC-17(2)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(6)
- NIST-800-53-SC-12(2)
- NIST-800-53-SC-12(3)
- NIST-800-53-SC-13
- PCI-DSSv4-2.2.7
- configure_crypto_policy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
- name: Verify that Crypto Policy is Set (runtime)
command: /usr/bin/update-crypto-policies --set {{ var_system_crypto_policy }}
tags:
- CCE-85776-3
- NIST-800-53-AC-17(2)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(6)
- NIST-800-53-SC-12(2)
- NIST-800-53-SC-12(3)
- NIST-800-53-SC-13
- PCI-DSSv4-2.2.7
- configure_crypto_policy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
var_system_crypto_policy='DEFAULT'
stderr_of_call=$(update-crypto-policies --set ${var_system_crypto_policy} 2>&1 > /dev/null)
rc=$?
if test "$rc" = 127; then
echo "$stderr_of_call" >&2
echo "Make sure that the script is installed on the remediated system." >&2
echo "See output of the 'dnf provides update-crypto-policies' command" >&2
echo "to see what package to (re)install" >&2
false # end with an error code
elif test "$rc" != 0; then
echo "Error invoking the update-crypto-policies script: $stderr_of_call" >&2
false # end with an error code
fi
|
Configure SSH to use System Crypto Policy
[ref]ruleCrypto Policies provide a centralized control over crypto algorithms usage of many packages.
SSH is supported by crypto policy, but the SSH configuration may be
set up to ignore it.
To check that Crypto Policies settings are configured correctly, ensure that
the CRYPTO_POLICY variable is either commented or not set at all
in the /etc/sysconfig/sshd . Rationale:Overriding the system crypto policy makes the behavior of the SSH service violate expectations,
and makes system configuration more fragmented. Identifiers:
CCE-85795-3 References:
CCI-001453, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.312(e)(1), 164.312(e)(2)(ii), CIP-003-8 R4.2, CIP-007-3 R5.1, CIP-007-3 R7.1, AC-17(a), AC-17(2), CM-6(a), MA-4(6), SC-13, FCS_SSH_EXT.1, FCS_SSHS_EXT.1, FCS_SSHC_EXT.1, Req-2.2, 2.2.7, SRG-OS-000250-GPOS-00093 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Configure SSH to use System Crypto Policy
lineinfile:
dest: /etc/sysconfig/sshd
state: absent
regexp: ^(?i)\s*CRYPTO_POLICY.*$
tags:
- CCE-85795-3
- NIST-800-53-AC-17(2)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(6)
- NIST-800-53-SC-13
- PCI-DSS-Req-2.2
- PCI-DSSv4-2.2.7
- configure_ssh_crypto_policy
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
Remediation Shell script: (show)
SSH_CONF="/etc/sysconfig/sshd"
sed -i "/^\s*CRYPTO_POLICY.*$/Id" $SSH_CONF
|
GNOME Desktop Environment
[ref]groupGNOME is a graphical desktop environment bundled with many Linux distributions that
allow users to easily interact with the operating system graphically rather than
textually. The GNOME Graphical Display Manager (GDM) provides login, logout, and user
switching contexts as well as display server management.
GNOME is developed by the GNOME Project and is considered the default
Red Hat Graphical environment.
For more information on GNOME and the GNOME Project, see https://www.gnome.org. |
contains 7 rules |
Configure GNOME Login Screen
[ref]groupIn the default GNOME desktop, the login is displayed after system boot
and can display user accounts, allow users to reboot the system, and allow users to
login automatically and/or with a guest account. The login screen should be configured
to prevent such behavior.
For more information about enforcing preferences in the GNOME3 environment using the DConf
configuration system, see https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/desktop_migration_and_administration_guide/> and the man page dconf(1) . |
contains 1 rule |
Disable GDM Unattended or Automatic Login
[ref]ruleThe GNOME Display Manager (GDM) can allow users to automatically login without
user interaction or credentials or unattended login. User should always be required to authenticate themselves
to the system that they are authorized to use. To disable user ability to automatically
login to the system, set the DISPLAYMANAGER_AUTOLOGIN=""
or DISPLAYMANAGER_PASSWORD_LESS_LOGIN="no" in the
/etc/sysconfig/displaymanager . For example:
DISPLAYMANAGER_AUTOLOGIN=""
DISPLAYMANAGER_PASSWORD_LESS_LOGIN="no" Rationale:Failure to restrict system access to authenticated users negatively impacts operating
system security. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85723-5
- DISA-STIG-SLES-15-040430
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSSv4-8.3.1
- gnome_gdm_disable_unattended_automatic_login
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
- name: Disable GDM Automatic Login
ini_file:
dest: /etc/sysconfig/displaymanager
section: null
option: DISPLAYMANAGER_AUTOLOGIN
value: '""'
no_extra_spaces: true
create: false
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85723-5
- DISA-STIG-SLES-15-040430
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSSv4-8.3.1
- gnome_gdm_disable_unattended_automatic_login
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
- name: Disable password less Login
ini_file:
dest: /etc/sysconfig/displaymanager
section: null
option: DISPLAYMANAGER_PASSWORD_LESS_LOGIN
value: '"no"'
no_extra_spaces: true
create: false
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85723-5
- DISA-STIG-SLES-15-040430
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSSv4-8.3.1
- gnome_gdm_disable_unattended_automatic_login
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
if ! (sed -n '/^DISPLAYMANAGER_AUTOLOGIN=\"\"/p' /etc/sysconfig/displaymanager)
then
sed -i "s/^DISPLAYMANAGER_AUTOLOGIN=.*/DISPLAYMANAGER_AUTOLOGIN=\"\"/g" /etc/sysconfig/displaymanager
fi
if ! (sed -n '/^DISPLAYMANAGER_PASSWORD_LESS_LOGIN=\"no\"/p' /etc/sysconfig/displaymanager)
then
sed -i "s/^DISPLAYMANAGER_PASSWORD_LESS_LOGIN=.*/DISPLAYMANAGER_PASSWORD_LESS_LOGIN=\"no\"/g" /etc/sysconfig/displaymanager
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Configure GNOME Screen Locking
[ref]groupIn the default GNOME3 desktop, the screen can be locked
by selecting the user name in the far right corner of the main panel and
selecting Lock.
The following sections detail commands to enforce idle activation of the screensaver,
screen locking, a blank-screen screensaver, and an idle activation time.
Because users should be trained to lock the screen when they
step away from the computer, the automatic locking feature is only
meant as a backup.
The root account can be screen-locked; however, the root account should
never be used to log into an X Windows environment and should only
be used to for direct login via console in emergency circumstances.
For more information about enforcing preferences in the GNOME3 environment using the DConf
configuration system, see http://wiki.gnome.org/dconf and
the man page dconf(1) . |
contains 5 rules |
Enable GNOME3 Screensaver Idle Activation
[ref]ruleTo activate the screensaver in the GNOME3 desktop after a period of inactivity,
add or set idle-activation-enabled to true in
/etc/dconf/db/local.d/00-security-settings . For example:
[org/gnome/desktop/screensaver]
idle-activation-enabled=true
Once the setting has been added, add a lock to
/etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/desktop/screensaver/idle-activation-enabled
After the settings have been set, run dconf update .Rationale:A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate
physical vicinity of the information system but does not logout because of the temporary nature of the absence.
Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity,
GNOME desktops can be configured to identify when a user's session has idled and take action to initiate the
session lock.
Enabling idle activation of the screensaver ensures the screensaver will
be activated after the idle delay. Applications requiring continuous,
real-time screen display (such as network management products) require the
login session does not have administrator rights and the display station is located in a
controlled-access area. Identifiers:
CCE-85783-9 References:
1, 12, 15, 16, 5.5.5, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000057, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-11(a), PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, 8.2.8, SRG-OS-000029-GPOS-00010 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85783-9
- CJIS-5.5.5
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_idle_activation_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Enable GNOME3 Screensaver Idle Activation
ini_file:
dest: /etc/dconf/db/local.d/00-security-settings
section: org/gnome/desktop/screensaver
option: idle-activation-enabled
value: 'true'
create: true
no_extra_spaces: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85783-9
- CJIS-5.5.5
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_idle_activation_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Prevent user modification of GNOME idle-activation-enabled
lineinfile:
path: /etc/dconf/db/local.d/locks/00-security-settings-lock
regexp: ^/org/gnome/desktop/screensaver/idle-activation-enabled$
line: /org/gnome/desktop/screensaver/idle-activation-enabled
create: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85783-9
- CJIS-5.5.5
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_idle_activation_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85783-9
- CJIS-5.5.5
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_idle_activation_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/screensaver\\]" "/etc/dconf/db/" \
| grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"
mkdir -p "${DBDIR}"
# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
if grep -q "^\\s*idle-activation-enabled\\s*=" "${SETTINGSFILES[@]}"
then
sed -Ei "s/(^\s*)idle-activation-enabled(\s*=)/#\1idle-activation-enabled\2/g" "${SETTINGSFILES[@]}"
fi
fi
[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/desktop/screensaver\\]" "${DCONFFILE}"
then
printf '%s\n' "[org/gnome/desktop/screensaver]" >> ${DCONFFILE}
fi
escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
if grep -q "^\\s*idle-activation-enabled\\s*=" "${DCONFFILE}"
then
sed -i "s/\\s*idle-activation-enabled\\s*=\\s*.*/idle-activation-enabled=${escaped_value}/g" "${DCONFFILE}"
else
sed -i "\\|\\[org/gnome/desktop/screensaver\\]|a\\idle-activation-enabled=${escaped_value}" "${DCONFFILE}"
fi
dconf update
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/desktop/screensaver/idle-activation-enabled$" "/etc/dconf/db/" \
| grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/local.d/locks"
mkdir -p "${LOCKSFOLDER}"
# Comment out the configurations in databases different from the target one
if [[ ! -z "${LOCKFILES}" ]]
then
sed -i -E "s|^/org/gnome/desktop/screensaver/idle-activation-enabled$|#&|" "${LOCKFILES[@]}"
fi
if ! grep -qr "^/org/gnome/desktop/screensaver/idle-activation-enabled$" /etc/dconf/db/local.d/
then
echo "/org/gnome/desktop/screensaver/idle-activation-enabled" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
fi
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set GNOME3 Screensaver Inactivity Timeout
[ref]ruleThe idle time-out value for inactivity in the GNOME3 desktop is configured via the idle-delay
setting must be set under an appropriate configuration file(s) in the /etc/dconf/db/local.d directory
and locked in /etc/dconf/db/local.d/locks directory to prevent user modification.
For example, to configure the system for a 15 minute delay, add the following to
/etc/dconf/db/local.d/00-security-settings :
[org/gnome/desktop/session]
idle-delay=uint32 900 Rationale:A session time-out lock is a temporary action taken when a user stops work and moves away from
the immediate physical vicinity of the information system but does not logout because of the
temporary nature of the absence. Rather than relying on the user to manually lock their operating
system session prior to vacating the vicinity, GNOME3 can be configured to identify when
a user's session has idled and take action to initiate a session lock. Identifiers:
CCE-85669-0 References:
1, 12, 15, 16, 5.5.5, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000057, CCI-000060, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-11(a), AC-11.1 (ii), PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, 8.2.8, SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012, SLES-15-010120, SV-234812r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85669-0
- CJIS-5.5.5
- DISA-STIG-SLES-15-010120
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(a)
- NIST-800-53-AC-11.1 (ii)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_idle_delay
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: XCCDF Value inactivity_timeout_value # promote to variable
set_fact:
inactivity_timeout_value: !!str 900
tags:
- always
- name: Set GNOME3 Screensaver Inactivity Timeout
ini_file:
dest: /etc/dconf/db/local.d/00-security-settings
section: org/gnome/desktop/session
option: idle-delay
value: uint32 {{ inactivity_timeout_value }}
create: true
no_extra_spaces: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85669-0
- CJIS-5.5.5
- DISA-STIG-SLES-15-010120
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(a)
- NIST-800-53-AC-11.1 (ii)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_idle_delay
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85669-0
- CJIS-5.5.5
- DISA-STIG-SLES-15-010120
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(a)
- NIST-800-53-AC-11.1 (ii)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_idle_delay
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
inactivity_timeout_value='900'
# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/session\\]" "/etc/dconf/db/" \
| grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"
mkdir -p "${DBDIR}"
# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
if grep -q "^\\s*idle-delay\\s*=" "${SETTINGSFILES[@]}"
then
sed -Ei "s/(^\s*)idle-delay(\s*=)/#\1idle-delay\2/g" "${SETTINGSFILES[@]}"
fi
fi
[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/desktop/session\\]" "${DCONFFILE}"
then
printf '%s\n' "[org/gnome/desktop/session]" >> ${DCONFFILE}
fi
escaped_value="$(sed -e 's/\\/\\\\/g' <<< "uint32 ${inactivity_timeout_value}")"
if grep -q "^\\s*idle-delay\\s*=" "${DCONFFILE}"
then
sed -i "s/\\s*idle-delay\\s*=\\s*.*/idle-delay=${escaped_value}/g" "${DCONFFILE}"
else
sed -i "\\|\\[org/gnome/desktop/session\\]|a\\idle-delay=${escaped_value}" "${DCONFFILE}"
fi
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable GNOME3 Screensaver Lock After Idle Period
[ref]rule
To activate locking of the screensaver in the GNOME3 desktop when it is activated,
run the following command to configure the SUSE operating system to allow the user to lock the GUI:
gsettings set org.gnome.desktop.lockdown disable-lock-screen false
Validate that disable-lock-screen has been set to false with the command:
gsettings get org.gnome.desktop.lockdown disable-lock-screen Rationale:A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity
of the information system but does not want to logout because of the temporary nature of the absense. Identifiers:
CCE-85766-4 References:
1, 12, 15, 16, 5.5.5, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000056, CCI-000058, CCI-000060, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, 8.2.8, SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011, SLES-15-010100, SV-234810r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_distribution == 'SLES'
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Enable GNOME3 Screensaver Lock After Idle Period
ini_file:
dest: /etc/dconf/db/local.d/00-security-settings
section: org/gnome/desktop/screensaver
option: lock-enabled
value: 'true'
create: true
no_extra_spaces: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_distribution != 'SLES'
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Prevent user modification of GNOME lock-enabled
lineinfile:
path: /etc/dconf/db/local.d/locks/00-security-settings-lock
regexp: ^/org/gnome/desktop/screensaver/lock-enabled$
line: /org/gnome/desktop/screensaver/lock-enabled
create: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_distribution != 'SLES'
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Enable GNOME3 Screensaver Lock After Idle Period
ini_file:
dest: /etc/dconf/db/local.d/00-security-settings
section: org/gnome/desktop/lockdown
option: disable-lock-screen
value: 'false'
create: true
no_extra_spaces: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_distribution == 'SLES'
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Prevent user modification of GNOME disable-lock-screen
lineinfile:
path: /etc/dconf/db/local.d/locks/00-security-settings-lock
regexp: ^/org/gnome/desktop/lockdown/disable-lock-screen$
line: /org/gnome/desktop/lockdown/disable-lock-screen
create: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_distribution == 'SLES'
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Check GNOME3 screenserver disable-lock-screen false
command: gsettings get org.gnome.desktop.lockdown disable-lock-screen
register: cmd_out
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_distribution == 'SLES'
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Update GNOME3 screenserver disable-lock-screen false
command: gsettings set org.gnome.desktop.lockdown disable-lock-screen false
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_distribution == 'SLES'
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
gsettings set org.gnome.desktop.lockdown disable-lock-screen false
# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/lockdown\\]" "/etc/dconf/db/" \
| grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"
mkdir -p "${DBDIR}"
# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
if grep -q "^\\s*disable-lock-screen\\s*=" "${SETTINGSFILES[@]}"
then
sed -Ei "s/(^\s*)disable-lock-screen(\s*=)/#\1disable-lock-screen\2/g" "${SETTINGSFILES[@]}"
fi
fi
[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/desktop/lockdown\\]" "${DCONFFILE}"
then
printf '%s\n' "[org/gnome/desktop/lockdown]" >> ${DCONFFILE}
fi
escaped_value="$(sed -e 's/\\/\\\\/g' <<< "false")"
if grep -q "^\\s*disable-lock-screen\\s*=" "${DCONFFILE}"
then
sed -i "s/\\s*disable-lock-screen\\s*=\\s*.*/disable-lock-screen=${escaped_value}/g" "${DCONFFILE}"
else
sed -i "\\|\\[org/gnome/desktop/lockdown\\]|a\\disable-lock-screen=${escaped_value}" "${DCONFFILE}"
fi
dconf update
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/desktop/lockdown/disable-lock-screen$" "/etc/dconf/db/" \
| grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/local.d/locks"
mkdir -p "${LOCKSFOLDER}"
# Comment out the configurations in databases different from the target one
if [[ ! -z "${LOCKFILES}" ]]
then
sed -i -E "s|^/org/gnome/desktop/lockdown/disable-lock-screen$|#&|" "${LOCKFILES[@]}"
fi
if ! grep -qr "^/org/gnome/desktop/lockdown/disable-lock-screen$" /etc/dconf/db/local.d/
then
echo "/org/gnome/desktop/lockdown/disable-lock-screen" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
fi
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Implement Blank Screensaver
[ref]rule
On SUSE users should set the screensaver to use publicly viewable images or blank screen
by doing the following:
Find the Settings menu and then navigate to the Background selection section
- Click "Activities" on the top left.
- Click "Show Applications" at the bottom of the Activities menu.
- Click the "Settings" icon.
- Click "Background" from left hand menu.
- Select image and set the Lock Screen image to the user's choice.
- Exit Settings Dialog.
To set the screensaver mode in the GNOME3 desktop to a blank screen,
add or set picture-uri to string '' in
/etc/dconf/db/local.d/00-security-settings . For example:
[org/gnome/desktop/screensaver]
picture-uri=string ''
Once the settings have been added, add a lock to
/etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/desktop/screensaver/picture-uri
After the settings have been set, run dconf update .Rationale:Setting the screensaver mode to blank-only conceals the
contents of the display from passersby. Identifiers:
CCE-85715-1 References:
1, 12, 15, 16, 5.5.5, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000060, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-11(1), CM-6(a), AC-11(1).1, PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, 8.2.8, SRG-OS-000031-GPOS-00012, SLES-15-010140, SV-234814r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85715-1
- CJIS-5.5.5
- DISA-STIG-SLES-15-010140
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(1)
- NIST-800-53-AC-11(1).1
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_mode_blank
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Implement Blank Screensaver
ini_file:
dest: /etc/dconf/db/local.d/00-security-settings
section: org/gnome/desktop/screensaver
option: picture-uri
value: string ''
create: true
no_extra_spaces: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85715-1
- CJIS-5.5.5
- DISA-STIG-SLES-15-010140
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(1)
- NIST-800-53-AC-11(1).1
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_mode_blank
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Prevent user modification of GNOME picture-uri
lineinfile:
path: /etc/dconf/db/local.d/locks/00-security-settings-lock
regexp: ^/org/gnome/desktop/screensaver/picture-uri$
line: /org/gnome/desktop/screensaver/picture-uri
create: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85715-1
- CJIS-5.5.5
- DISA-STIG-SLES-15-010140
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(1)
- NIST-800-53-AC-11(1).1
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_mode_blank
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85715-1
- CJIS-5.5.5
- DISA-STIG-SLES-15-010140
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(1)
- NIST-800-53-AC-11(1).1
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- dconf_gnome_screensaver_mode_blank
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/screensaver\\]" "/etc/dconf/db/" \
| grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"
mkdir -p "${DBDIR}"
# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
if grep -q "^\\s*picture-uri\\s*=" "${SETTINGSFILES[@]}"
then
sed -Ei "s/(^\s*)picture-uri(\s*=)/#\1picture-uri\2/g" "${SETTINGSFILES[@]}"
fi
fi
[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/desktop/screensaver\\]" "${DCONFFILE}"
then
printf '%s\n' "[org/gnome/desktop/screensaver]" >> ${DCONFFILE}
fi
escaped_value="$(sed -e 's/\\/\\\\/g' <<< "string ''")"
if grep -q "^\\s*picture-uri\\s*=" "${DCONFFILE}"
then
sed -i "s/\\s*picture-uri\\s*=\\s*.*/picture-uri=${escaped_value}/g" "${DCONFFILE}"
else
sed -i "\\|\\[org/gnome/desktop/screensaver\\]|a\\picture-uri=${escaped_value}" "${DCONFFILE}"
fi
dconf update
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/desktop/screensaver/picture-uri$" "/etc/dconf/db/" \
| grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/local.d/locks"
mkdir -p "${LOCKSFOLDER}"
# Comment out the configurations in databases different from the target one
if [[ ! -z "${LOCKFILES}" ]]
then
sed -i -E "s|^/org/gnome/desktop/screensaver/picture-uri$|#&|" "${LOCKFILES[@]}"
fi
if ! grep -qr "^/org/gnome/desktop/screensaver/picture-uri$" /etc/dconf/db/local.d/
then
echo "/org/gnome/desktop/screensaver/picture-uri" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
fi
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure Users Cannot Change GNOME3 Session Idle Settings
[ref]ruleIf not already configured, ensure that users cannot change GNOME3 session idle settings
by adding /org/gnome/desktop/session/idle-delay
to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/desktop/session/idle-delay
After the settings have been set, run dconf update .Rationale:A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate
physical vicinity of the information system but does not logout because of the temporary nature of the absence.
Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity,
GNOME desktops can be configured to identify when a user's session has idled and take action to initiate the
session lock. As such, users should not be allowed to change session settings. Identifiers:
CCE-91245-1 References:
1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000057, CCI-000060, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, 8.2.8, SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012, SLES-15-010120, SV-234812r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/desktop/session/idle-delay$" "/etc/dconf/db/" \
| grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/local.d/locks"
mkdir -p "${LOCKSFOLDER}"
# Comment out the configurations in databases different from the target one
if [[ ! -z "${LOCKFILES}" ]]
then
sed -i -E "s|^/org/gnome/desktop/session/idle-delay$|#&|" "${LOCKFILES[@]}"
fi
if ! grep -qr "^/org/gnome/desktop/session/idle-delay$" /etc/dconf/db/local.d/
then
echo "/org/gnome/desktop/session/idle-delay" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
fi
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Make sure that the dconf databases are up-to-date with regards to respective keyfiles
[ref]ruleBy default, DConf uses a binary database as a data backend.
The system-level database is compiled from keyfiles in the /etc/dconf/db/
directory by the dconf update command. More specifically, content present
in the following directories:
/etc/dconf/db/gdm.d
/etc/dconf/db/local.d Rationale:Unlike text-based keyfiles, the binary database is impossible to check by OVAL.
Therefore, in order to evaluate dconf configuration, both have to be true at the same time -
configuration files have to be compliant, and the database needs to be more recent than those keyfiles,
which gives confidence that it reflects them. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83288-1
- DISA-STIG-SLES-15-010090
- PCI-DSS-Req-6.2
- PCI-DSSv4-8.2.8
- dconf_db_up_to_date
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
- name: Run dconf update
ansible.builtin.command:
cmd: dconf update
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83288-1
- DISA-STIG-SLES-15-010090
- PCI-DSS-Req-6.2
- PCI-DSSv4-8.2.8
- dconf_db_up_to_date
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Sudo , which stands for "su 'do'", provides the ability to delegate authority
to certain users, groups of users, or system administrators. When configured for system
users and/or groups, Sudo can allow a user or group to execute privileged commands
that normally only root is allowed to execute.
For more information on Sudo and addition Sudo configuration options, see
https://www.sudo.ws.
|
contains 5 rules |
Install sudo Package
[ref]ruleThe sudo package can be installed with the following command:
$ sudo zypper install sudo Rationale:sudo is a program designed to allow a system administrator to give
limited root privileges to users and log root activity. The basic philosophy
is to give as few privileges as possible but still allow system users to
get their work done. Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_sudo
class install_sudo {
package { 'sudo':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "sudo"
version = "*"
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure sudo is installed
package:
name: sudo
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91183-4
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_sudo_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "sudo"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo use_pty
[ref]ruleThe sudo use_pty tag, when specified, will only execute sudo
commands from users logged in to a real tty.
This should be enabled by making sure that the use_pty tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . Rationale:Requiring that sudo commands be run in a pseudo-terminal can prevent an attacker from retaining
access to the user's terminal after the main program has finished executing. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-91190-9
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_add_use_pty
- name: Ensure use_pty is enabled in /etc/sudoers
lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults.*\buse_pty\b.*$
line: Defaults use_pty
validate: /usr/sbin/visudo -cf %s
when: '"sudo" in ansible_facts.packages'
tags:
- CCE-91190-9
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_add_use_pty
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q sudo; then
if /usr/sbin/visudo -qcf /etc/sudoers; then
cp /etc/sudoers /etc/sudoers.bak
if ! grep -P '^[\s]*Defaults[\s]*\buse_pty\b.*$' /etc/sudoers; then
# sudoers file doesn't define Option use_pty
echo "Defaults use_pty" >> /etc/sudoers
fi
# Check validity of sudoers and cleanup bak
if /usr/sbin/visudo -qcf /etc/sudoers; then
rm -f /etc/sudoers.bak
else
echo "Fail to validate remediated /etc/sudoers, reverting to original file."
mv /etc/sudoers.bak /etc/sudoers
false
fi
else
echo "Skipping remediation, /etc/sudoers failed to validate"
false
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure Sudo Logfile Exists - sudo logfile
[ref]ruleA custom log sudo file can be configured with the 'logfile' tag. This rule configures
a sudo custom logfile at the default location suggested by CIS, which uses
/var/log/sudo.log. Rationale:A sudo log file simplifies auditing of sudo commands. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-91311-1
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- sudo_custom_logfile
- name: XCCDF Value var_sudo_logfile # promote to variable
set_fact:
var_sudo_logfile: !!str /var/log/sudo.log
tags:
- always
- name: Ensure logfile is enabled with the appropriate value in /etc/sudoers
lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults\s(.*)\blogfile=[-]?.+\b(.*)$
line: Defaults \1logfile={{ var_sudo_logfile }}\2
validate: /usr/sbin/visudo -cf %s
backrefs: true
register: edit_sudoers_logfile_option
when: '"sudo" in ansible_facts.packages'
tags:
- CCE-91311-1
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- sudo_custom_logfile
- name: Enable logfile option with appropriate value in /etc/sudoers
lineinfile:
path: /etc/sudoers
line: Defaults logfile={{ var_sudo_logfile }}
validate: /usr/sbin/visudo -cf %s
when:
- '"sudo" in ansible_facts.packages'
- edit_sudoers_logfile_option is defined and not edit_sudoers_logfile_option.changed
tags:
- CCE-91311-1
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- sudo_custom_logfile
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q sudo; then
var_sudo_logfile='/var/log/sudo.log'
if /usr/sbin/visudo -qcf /etc/sudoers; then
cp /etc/sudoers /etc/sudoers.bak
if ! grep -P '^[\s]*Defaults[\s]*\blogfile=("(?:\\"|\\\\|[^"\\\n])*"\B|[^"](?:(?:\\,|\\"|\\ |\\\\|[^", \\\n])*)\b)\b.*$' /etc/sudoers; then
# sudoers file doesn't define Option logfile
echo "Defaults logfile=${var_sudo_logfile}" >> /etc/sudoers
else
# sudoers file defines Option logfile, remediate if appropriate value is not set
if ! grep -P "^[\s]*Defaults.*\blogfile=${var_sudo_logfile}\b.*$" /etc/sudoers; then
escaped_variable=${var_sudo_logfile//$'/'/$'\/'}
sed -Ei "s/(^[\s]*Defaults.*\blogfile=)[-]?.+(\b.*$)/\1$escaped_variable\2/" /etc/sudoers
fi
fi
# Check validity of sudoers and cleanup bak
if /usr/sbin/visudo -qcf /etc/sudoers; then
rm -f /etc/sudoers.bak
else
echo "Fail to validate remediated /etc/sudoers, reverting to original file."
mv /etc/sudoers.bak /etc/sudoers
false
fi
else
echo "Skipping remediation, /etc/sudoers failed to validate"
false
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure Users Re-Authenticate for Privilege Escalation - sudo
[ref]ruleThe sudo NOPASSWD and !authenticate option, when
specified, allows a user to execute commands using sudo without having to
authenticate. This should be disabled by making sure that
NOPASSWD and/or !authenticate do not exist in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ ." Rationale:Without re-authentication, users may access resources or perform tasks for which they
do not have authorization.
When operating systems provide the capability to escalate a functional capability, it
is critical that the user re-authenticate. Identifiers:
CCE-85673-2 References:
1, 12, 15, 16, 5, DSS05.04, DSS05.10, DSS06.03, DSS06.10, CCI-002038, 4.3.3.5.1, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-11, CM-6(a), PR.AC-1, PR.AC-7, 2.2.6, SRG-OS-000373-GPOS-00156, SLES-15-010450, SV-234853r854199_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Find /etc/sudoers.d/ files
ansible.builtin.find:
paths:
- /etc/sudoers.d/
register: sudoers
tags:
- CCE-85673-2
- DISA-STIG-SLES-15-010450
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_authentication
- name: Remove lines containing NOPASSWD from sudoers files
ansible.builtin.replace:
regexp: (^(?!#).*[\s]+NOPASSWD[\s]*\:.*$)
replace: '# \g<1>'
path: '{{ item.path }}'
validate: /usr/sbin/visudo -cf %s
with_items:
- path: /etc/sudoers
- '{{ sudoers.files }}'
tags:
- CCE-85673-2
- DISA-STIG-SLES-15-010450
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_authentication
- name: Find /etc/sudoers.d/ files
ansible.builtin.find:
paths:
- /etc/sudoers.d/
register: sudoers
tags:
- CCE-85673-2
- DISA-STIG-SLES-15-010450
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_authentication
- name: Remove lines containing !authenticate from sudoers files
ansible.builtin.replace:
regexp: (^(?!#).*[\s]+\!authenticate.*$)
replace: '# \g<1>'
path: '{{ item.path }}'
validate: /usr/sbin/visudo -cf %s
with_items:
- path: /etc/sudoers
- '{{ sudoers.files }}'
tags:
- CCE-85673-2
- DISA-STIG-SLES-15-010450
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_authentication
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
for f in /etc/sudoers /etc/sudoers.d/* ; do
if [ ! -e "$f" ] ; then
continue
fi
matching_list=$(grep -P '^(?!#).*[\s]+NOPASSWD[\s]*\:.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "NOPASSWD" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
/usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
fi
done
for f in /etc/sudoers /etc/sudoers.d/* ; do
if [ ! -e "$f" ] ; then
continue
fi
matching_list=$(grep -P '^(?!#).*[\s]+\!authenticate.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "!authenticate" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
/usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
fi
done
|
Require Re-Authentication When Using the sudo Command
[ref]ruleThe sudo timestamp_timeout tag sets the amount of time sudo password prompt waits.
The default timestamp_timeout value is 5 minutes.
The timestamp_timeout should be configured by making sure that the
timestamp_timeout tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ .
If the value is set to an integer less than 0, the user's time stamp will not expire
and the user will not have to re-authenticate for privileged actions until the user's session is terminated. Rationale:Without re-authentication, users may access resources or perform tasks for which they
do not have authorization.
When operating systems provide the capability to escalate a functional capability, it
is critical that the user re-authenticate. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85764-9
- DISA-STIG-SLES-15-020102
- NIST-800-53-IA-11
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_reauthentication
- name: XCCDF Value var_sudo_timestamp_timeout # promote to variable
set_fact:
var_sudo_timestamp_timeout: !!str 5
tags:
- always
- name: Require Re-Authentication When Using the sudo Command - Find /etc/sudoers.d/*
files containing 'Defaults timestamp_timeout'
ansible.builtin.find:
path: /etc/sudoers.d
patterns: '*'
contains: ^[\s]*Defaults\s.*\btimestamp_timeout[\s]*=.*
register: sudoers_d_defaults_timestamp_timeout
when: '"sudo" in ansible_facts.packages'
tags:
- CCE-85764-9
- DISA-STIG-SLES-15-020102
- NIST-800-53-IA-11
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_reauthentication
- name: Require Re-Authentication When Using the sudo Command - Remove 'Defaults timestamp_timeout'
from /etc/sudoers.d/* files
ansible.builtin.lineinfile:
path: '{{ item.path }}'
regexp: ^[\s]*Defaults\s.*\btimestamp_timeout[\s]*=.*
state: absent
with_items: '{{ sudoers_d_defaults_timestamp_timeout.files }}'
when: '"sudo" in ansible_facts.packages'
tags:
- CCE-85764-9
- DISA-STIG-SLES-15-020102
- NIST-800-53-IA-11
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_reauthentication
- name: Require Re-Authentication When Using the sudo Command - Ensure timestamp_timeout
has the appropriate value in /etc/sudoers
ansible.builtin.lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults\s(.*)\btimestamp_timeout[\s]*=[\s]*[-]?\w+\b(.*)$
line: Defaults \1timestamp_timeout={{ var_sudo_timestamp_timeout }}\2
validate: /usr/sbin/visudo -cf %s
backrefs: true
register: edit_sudoers_timestamp_timeout_option
when: '"sudo" in ansible_facts.packages'
tags:
- CCE-85764-9
- DISA-STIG-SLES-15-020102
- NIST-800-53-IA-11
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_reauthentication
- name: Require Re-Authentication When Using the sudo Command - Enable timestamp_timeout
option with correct value in /etc/sudoers
ansible.builtin.lineinfile:
path: /etc/sudoers
line: Defaults timestamp_timeout={{ var_sudo_timestamp_timeout }}
validate: /usr/sbin/visudo -cf %s
when:
- '"sudo" in ansible_facts.packages'
- |
edit_sudoers_timestamp_timeout_option is defined and not edit_sudoers_timestamp_timeout_option.changed
tags:
- CCE-85764-9
- DISA-STIG-SLES-15-020102
- NIST-800-53-IA-11
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_reauthentication
- name: Require Re-Authentication When Using the sudo Command - Remove timestamp_timeout
wrong values in /etc/sudoers
ansible.builtin.lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults\s.*\btimestamp_timeout[\s]*=[\s]*(?!{{ var_sudo_timestamp_timeout
}}\b)[-]?\w+\b.*$
state: absent
validate: /usr/sbin/visudo -cf %s
when: '"sudo" in ansible_facts.packages'
tags:
- CCE-85764-9
- DISA-STIG-SLES-15-020102
- NIST-800-53-IA-11
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_reauthentication
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q sudo; then
var_sudo_timestamp_timeout='5'
if grep -Px '^[\s]*Defaults.*timestamp_timeout[\s]*=.*' /etc/sudoers.d/*; then
find /etc/sudoers.d/ -type f -exec sed -Ei "/^[[:blank:]]*Defaults.*timestamp_timeout[[:blank:]]*=.*/d" {} \;
fi
if /usr/sbin/visudo -qcf /etc/sudoers; then
cp /etc/sudoers /etc/sudoers.bak
if ! grep -P '^[\s]*Defaults.*timestamp_timeout[\s]*=[\s]*[-]?\w+.*$' /etc/sudoers; then
# sudoers file doesn't define Option timestamp_timeout
echo "Defaults timestamp_timeout=${var_sudo_timestamp_timeout}" >> /etc/sudoers
else
# sudoers file defines Option timestamp_timeout, remediate wrong values if present
if grep -qP "^[\s]*Defaults\s.*\btimestamp_timeout[\s]*=[\s]*(?!${var_sudo_timestamp_timeout}\b)[-]?\w+\b.*$" /etc/sudoers; then
sed -Ei "s/(^[[:blank:]]*Defaults.*timestamp_timeout[[:blank:]]*=)[[:blank:]]*[-]?\w+(.*$)/\1${var_sudo_timestamp_timeout}\2/" /etc/sudoers
fi
fi
# Check validity of sudoers and cleanup bak
if /usr/sbin/visudo -qcf /etc/sudoers; then
rm -f /etc/sudoers.bak
else
echo "Fail to validate remediated /etc/sudoers, reverting to original file."
mv /etc/sudoers.bak /etc/sudoers
false
fi
else
echo "Skipping remediation, /etc/sudoers failed to validate"
false
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Updating Software
[ref]groupThe zypper command line tool is used to install and
update software packages. The system also provides a graphical
software update tool in the System menu, in the Administration submenu,
called Software Update.
SUSE Linux Enterprise 15 systems contain an installed software catalog called
the RPM database, which records metadata of installed packages. Consistently using
zypper or the graphical Software Update for all software installation
allows for insight into the current inventory of installed software on the system.
|
contains 4 rules |
Ensure gpgcheck Enabled In Main zypper Configuration
[ref]ruleThe gpgcheck option controls whether
RPM packages' signatures are always checked prior to installation.
To configure zypper to check package signatures before installing
them, ensure the following line appears in /etc/zypp/zypp.conf in
the [main] section:
gpgcheck=1 Rationale:Changes to any software components can have significant effects on the
overall security of the operating system. This requirement ensures the
software has not been tampered with and that it has been provided by a
trusted vendor.
Accordingly, patches, service packs, device drivers, or operating system
components must be signed with a certificate recognized and approved by the
organization.
Verifying the authenticity of the software prior to installation
validates the integrity of the patch or upgrade received from a vendor.
This ensures the software has not been tampered with and that it has been
provided by a trusted vendor. Self-signed certificates are disallowed by
this requirement. Certificates used to verify the software must be from an
approved Certificate Authority (CA). Identifiers:
CCE-83290-7 References:
BP28(R15), 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, FPT_TUD_EXT.1, FPT_TUD_EXT.2, Req-6.2, 6.3.3, SRG-OS-000366-GPOS-00153, SLES-15-010430, 1.2.3, SV-234852r877463_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83290-7
- CJIS-5.10.4.1
- DISA-STIG-SLES-15-010430
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- PCI-DSSv4-6.3.3
- configure_strategy
- ensure_gpgcheck_globally_activated
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- name: Ensure GPG check is globally activated
ini_file:
dest: /etc/zypp/zypp.conf
section: main
option: gpgcheck
value: 1
no_extra_spaces: true
create: false
when: '"zypper" in ansible_facts.packages'
tags:
- CCE-83290-7
- CJIS-5.10.4.1
- DISA-STIG-SLES-15-010430
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- PCI-DSSv4-6.3.3
- configure_strategy
- ensure_gpgcheck_globally_activated
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q zypper; then
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^gpgcheck")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^gpgcheck\\>" "/etc/zypp/zypp.conf"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^gpgcheck\\>.*/$escaped_formatted_output/gi" "/etc/zypp/zypp.conf"
else
if [[ -s "/etc/zypp/zypp.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/zypp/zypp.conf" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/zypp/zypp.conf"
fi
cce="CCE-83290-7"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "/etc/zypp/zypp.conf" >> "/etc/zypp/zypp.conf"
printf '%s\n' "$formatted_output" >> "/etc/zypp/zypp.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure gpgcheck Enabled for All zypper Package Repositories
[ref]ruleTo ensure signature checking is not disabled for
any repos, remove any lines from files in /etc/yum.repos.d of the form:
gpgcheck=0 Rationale:Verifying the authenticity of the software prior to installation validates
the integrity of the patch or upgrade received from a vendor. This ensures
the software has not been tampered with and that it has been provided by a
trusted vendor. Self-signed certificates are disallowed by this
requirement. Certificates used to verify the software must be from an
approved Certificate Authority (CA)." Identifiers:
CCE-85797-9 References:
BP28(R15), 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, FPT_TUD_EXT.1, FPT_TUD_EXT.2, Req-6.2, 6.3.3, SRG-OS-000366-GPOS-00153, 1.2.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Grep for zypper repo section names
shell: |
set -o pipefail
grep -HEr '^\[.+\]' -r /etc/zypp/repos.d/
register: repo_grep_results
failed_when: repo_grep_results.rc not in [0, 1]
changed_when: false
tags:
- CCE-85797-9
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- PCI-DSSv4-6.3.3
- enable_strategy
- ensure_gpgcheck_never_disabled
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- name: Set gpgcheck=1 for each zypper repo
ini_file:
path: '{{ item[0] }}'
section: '{{ item[1] }}'
option: gpgcheck
value: '1'
no_extra_spaces: true
loop: '{{ repo_grep_results.stdout | regex_findall( ''(.+\.repo):\[(.+)\]\n?'' )
}}'
tags:
- CCE-85797-9
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- PCI-DSSv4-6.3.3
- enable_strategy
- ensure_gpgcheck_never_disabled
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
Remediation Shell script: (show)
sed -i 's/gpgcheck\s*=.*/gpgcheck=1/g' /etc/zypp/repos.d/*
|
Ensure SUSE GPG Key Installed
[ref]ruleTo ensure the system can cryptographically verify base software packages
come from SUSE (and to connect to the SUSE to receive them),
the SUSE GPG key must properly be installed. To install the SUSE GPG
key, run:
$ sudo zypper install suse-build-key
If the system is not connected to the Internet or an RHN Satellite, then
install the SUSE GPG key from trusted media such as the SUSE
installation CD-ROM or DVD. Assuming the disc is mounted in
/media/cdrom , use the following command as the root user to import
it into the keyring:
$ sudo rpm --import /media/cdrom/content.key or
$ sudo rpm --import /media/cdrom/repodata/repomd.xml.key
Alternatively, the key may be pre-loaded during the SUSE installation. In
such cases, one can use the repository cache files to install the key,
for example by running the following command:
sudo rpm --import /var/cache/zypp/raw/Basesystem_Module_15_SP2_x86_64:SLE-Module-Basesystem15-SP2-Pool/repodata/repomd.xml.key Rationale:Changes to software components can have significant effects on the overall
security of the operating system. This requirement ensures the software has
not been tampered with and that it has been provided by a trusted vendor.
The SUSE GPG key is necessary to cryptographically verify packages are
from SUSE. Identifiers:
CCE-85796-1 References:
BP28(R15), 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CIP-003-8 R4.2, CIP-003-8 R6, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), PR.DS-6, PR.DS-8, PR.IP-1, FPT_TUD_EXT.1, FPT_TUD_EXT.2, Req-6.2, 6.3.3, SRG-OS-000366-GPOS-00153 Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Read permission of GPG key directory
stat:
path: /usr/lib/rpm/gnupg/keys
register: suse_gpg_key_directory_permission
check_mode: false
tags:
- CCE-85796-1
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- PCI-DSSv4-6.3.3
- ensure_suse_gpgkey_installed
- high_severity
- medium_complexity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- name: Set Valid fingerprint
set_fact:
suse_gpg_valid_fingerprints: FEAB502539D846DB2C0961CA70AF9E8139DB7C82
tags:
- CCE-85796-1
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- PCI-DSSv4-6.3.3
- ensure_suse_gpgkey_installed
- high_severity
- medium_complexity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- name: Read signatures in GPG key
shell: |-
set -o pipefail
gpg --with-fingerprint --with-colons "{{ item }}" | grep -A1 "^pub" | grep "^fpr" | cut -d ":" -f 10
changed_when: false
register: suse_gpg_fingerprints
check_mode: false
with_fileglob: /usr/lib/rpm/gnupg/keys/*.asc
tags:
- CCE-85796-1
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- PCI-DSSv4-6.3.3
- ensure_suse_gpgkey_installed
- high_severity
- medium_complexity
- medium_disruption
- no_reboot_needed
- restrict_strategy
- name: Import SUSE GPG key
rpm_key:
state: present
key: '{{ item.item }}'
when:
- suse_gpg_key_directory_permission.stat.mode <= '0755'
- item.stdout == suse_gpg_valid_fingerprints
- suse_gpg_fingerprints | length > 0
with_items: '{{ suse_gpg_fingerprints.results }}'
tags:
- CCE-85796-1
- CJIS-5.10.4.1
- NIST-800-171-3.4.8
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- PCI-DSSv4-6.3.3
- ensure_suse_gpgkey_installed
- high_severity
- medium_complexity
- medium_disruption
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# The fingerprint below is retrieved from https://www.suse.com/support/security/keys/
readonly SUSE_RELEASE_FINGERPRINT="FEAB502539D846DB2C0961CA70AF9E8139DB7C82"
# Location of the key we would like to import (once it's integrity verified)
readonly SUSE_RELEASE_KEY_PATTERN="/usr/lib/rpm/gnupg/keys/*.asc"
RPM_GPG_DIR_PERMS=$(stat -c %a /usr/lib/rpm/gnupg/keys)
# Verify keys directory permissions are safe
if [ "${RPM_GPG_DIR_PERMS}" -le "755" ]
then
for KEYFILE in $SUSE_RELEASE_KEY_PATTERN; do
# If they are safe, try to obtain fingerprints from the key file
# (to ensure there won't be e.g. CRC error).
readarray -t GPG_OUT < <(gpg --with-fingerprint --with-colons "$KEYFILE" | grep -A1 "^pub" | grep "^fpr" | cut -d ":" -f 10)
GPG_RESULT=$?
# No CRC error, safe to proceed
if [ "${GPG_RESULT}" -eq "0" ]
then
echo "${GPG_OUT[*]}" | grep -vE "${SUSE_RELEASE_FINGERPRINT}" || {
# In this rule we care on of release build key so we will skip possible keys for backports, etc
rpm --import "${KEYFILE}"
break;
}
fi
done
fi
|
Ensure Software Patches Installed
[ref]rule
If the system is configured for online updates, invoking the following command will list available
security updates:
$ sudo zypper refresh && sudo zypper list-patches -g security
NOTE: U.S. Defense systems are required to be patched within 30 days or sooner as local policy
dictates.Rationale:Installing software updates is a fundamental mitigation against
the exploitation of publicly-known vulnerabilities. If the most
recent security patches and updates are not installed, unauthorized
users may take advantage of weaknesses in the unpatched software. The
lack of prompt attention to patching could result in a system compromise. Identifiers:
CCE-83261-8 References:
BP28(R08), 18, 20, 4, 5.10.4.1, APO12.01, APO12.02, APO12.03, APO12.04, BAI03.10, DSS05.01, DSS05.02, CCI-000366, CCI-001227, 4.2.3, 4.2.3.12, 4.2.3.7, 4.2.3.9, A.12.6.1, A.14.2.3, A.16.1.3, A.18.2.2, A.18.2.3, SI-2(5), SI-2(c), CM-6(a), ID.RA-1, PR.IP-12, FMT_MOF_EXT.1, Req-6.2, 6.3.3, SRG-OS-000480-GPOS-00227, SLES-15-010010, 1.9, SV-234802r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | true |
---|
Strategy: | patch |
---|
- name: Security patches are up to date
package:
name: '*'
state: latest
tags:
- CCE-83261-8
- CJIS-5.10.4.1
- DISA-STIG-SLES-15-010010
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-2(5)
- NIST-800-53-SI-2(c)
- PCI-DSS-Req-6.2
- PCI-DSSv4-6.3.3
- high_disruption
- low_complexity
- medium_severity
- patch_strategy
- reboot_required
- security_patches_up_to_date
- skip_ansible_lint
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | true |
---|
Strategy: | patch |
---|
zypper patch -g security -y
|
Account and Access Control
[ref]groupIn traditional Unix security, if an attacker gains
shell access to a certain login account, they can perform any action
or access any file to which that account has access. Therefore,
making it more difficult for unauthorized people to gain shell
access to accounts, particularly to privileged accounts, is a
necessary part of securing a system. This section introduces
mechanisms for restricting access to accounts under
SUSE Linux Enterprise 15. |
contains 39 rules |
Warning Banners for System Accesses
[ref]groupEach system should expose as little information about
itself as possible.
System banners, which are typically displayed just before a
login prompt, give out information about the service or the host's
operating system. This might include the distribution name and the
system kernel version, and the particular version of a network
service. This information can assist intruders in gaining access to
the system as it can reveal whether the system is running
vulnerable software. Most network services can be configured to
limit what information is displayed.
Many organizations implement security policies that require a
system banner provide notice of the system's ownership, provide
warning to unauthorized users, and remind authorized users of their
consent to monitoring. |
contains 3 rules |
Verify Group Ownership of System Login Banner for Remote Connections
[ref]rule
To properly set the group owner of /etc/issue.net , run the command:
$ sudo chgrp root /etc/issue.net Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
Proper group ownership will ensure that only root user can modify the banner. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/issue.net
stat:
path: /etc/issue.net
register: file_exists
tags:
- CCE-91358-2
- PCI-DSSv4-1.2.8
- configure_strategy
- file_groupowner_etc_issue_net
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/issue.net
file:
path: /etc/issue.net
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91358-2
- PCI-DSSv4-1.2.8
- configure_strategy
- file_groupowner_etc_issue_net
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/issue.net
|
Verify ownership of System Login Banner for Remote Connections
[ref]rule
To properly set the owner of /etc/issue.net , run the command:
$ sudo chown root /etc/issue.net Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
Proper ownership will ensure that only root user can modify the banner. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/issue.net
stat:
path: /etc/issue.net
register: file_exists
tags:
- CCE-91359-0
- PCI-DSSv4-1.2.8
- configure_strategy
- file_owner_etc_issue_net
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/issue.net
file:
path: /etc/issue.net
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91359-0
- PCI-DSSv4-1.2.8
- configure_strategy
- file_owner_etc_issue_net
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/issue.net
|
Verify permissions on System Login Banner for Remote Connections
[ref]rule
To properly set the permissions of /etc/issue.net , run the command:
$ sudo chmod 0644 /etc/issue.net Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
Proper permissions will ensure that only root user can modify the banner. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/issue.net
stat:
path: /etc/issue.net
register: file_exists
tags:
- CCE-91357-4
- PCI-DSSv4-1.2.8
- configure_strategy
- file_permissions_etc_issue_net
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/issue.net
file:
path: /etc/issue.net
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91357-4
- PCI-DSSv4-1.2.8
- configure_strategy
- file_permissions_etc_issue_net
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/issue.net
|
Protect Accounts by Configuring PAM
[ref]groupPAM, or Pluggable Authentication Modules, is a system
which implements modular authentication for Linux programs. PAM provides
a flexible and configurable architecture for authentication, and it should be configured
to minimize exposure to unnecessary risk. This section contains
guidance on how to accomplish that.
PAM is implemented as a set of shared objects which are
loaded and invoked whenever an application wishes to authenticate a
user. Typically, the application must be running as root in order
to take advantage of PAM, because PAM's modules often need to be able
to access sensitive stores of account information, such as /etc/shadow.
Traditional privileged network listeners
(e.g. sshd) or SUID programs (e.g. sudo) already meet this
requirement. An SUID root application, userhelper, is provided so
that programs which are not SUID or privileged themselves can still
take advantage of PAM.
PAM looks in the directory /etc/pam.d for
application-specific configuration information. For instance, if
the program login attempts to authenticate a user, then PAM's
libraries follow the instructions in the file /etc/pam.d/login
to determine what actions should be taken.
One very important file in /etc/pam.d is
/etc/pam.d/system-auth . This file, which is included by
many other PAM configuration files, defines 'default' system authentication
measures. Modifying this file is a good way to make far-reaching
authentication changes, for instance when implementing a
centralized authentication service. Warning:
Be careful when making changes to PAM's configuration files.
The syntax for these files is complex, and modifications can
have unexpected consequences. The default configurations shipped
with applications should be sufficient for most users. |
contains 12 rules |
Set Lockouts for Failed Password Attempts
[ref]groupThe pam_faillock PAM module provides the capability to
lock out user accounts after a number of failed login attempts. Its
documentation is available in
/usr/share/doc/pam-VERSION/txts/README.pam_faillock .
Warning:
Locking out user accounts presents the
risk of a denial-of-service attack. The lockout policy
must weigh whether the risk of such a
denial-of-service attack outweighs the benefits of thwarting
password guessing attacks. |
contains 3 rules |
Limit Password Reuse
[ref]ruleDo not allow users to reuse recent passwords. This can be accomplished by using the
remember option for the pam_unix or pam_pwhistory PAM modules. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report. Warning:
Newer versions of authselect contain an authselect feature to easily and properly
enable pam_pwhistory.so module. If this feature is not yet available in your
system, an authselect custom profile must be used to avoid integrity issues in PAM files. Rationale:Preventing re-use of previous passwords helps ensure that a compromised password is not
re-used by a user. Identifiers:
CCE-85678-1 References:
BP28(R18), 1, 12, 15, 16, 5, 5.6.2.1.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.8, CCI-000200, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(1)(e), IA-5(1).1(v), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.5, 8.3.7, SRG-OS-000077-GPOS-00045, SLES-15-020250, SV-234894r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85678-1
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020250
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: XCCDF Value var_password_pam_unix_remember # promote to variable
set_fact:
var_password_pam_unix_remember: !!str 4
tags:
- always
- name: Limit Password Reuse - Check if system relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85678-1
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020250
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Limit Password Reuse - Collect the available authselect features
ansible.builtin.command:
cmd: authselect list-features minimal
register: result_authselect_available_features
changed_when: false
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- CCE-85678-1
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020250
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Limit Password Reuse - Enable pam_pwhistory.so using authselect feature
block:
- name: Limit Password Reuse - Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Limit Password Reuse - Informative message based on the authselect integrity
check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because an authselect profile was not
selected or the selected profile is not intact.
- It is not recommended to manually edit the PAM files when authselect tool
is available.
- In cases where the default authselect profile does not cover a specific demand,
a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Limit Password Reuse - Get authselect current features
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Limit Password Reuse - Ensure "with-pwhistory" feature is enabled using
authselect tool
ansible.builtin.command:
cmd: authselect enable-feature with-pwhistory
register: result_authselect_enable_feature_cmd
when:
- result_authselect_check_cmd is success
- result_authselect_features.stdout is not search("with-pwhistory")
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_enable_feature_cmd is not skipped
- result_authselect_enable_feature_cmd is success
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
- result_authselect_available_features.stdout is search("with-pwhistory")
tags:
- CCE-85678-1
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020250
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Limit Password Reuse - Enable pam_pwhistory.so in appropriate PAM files
block:
- name: Limit Password Reuse - Define the PAM file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/common-password
- name: Limit Password Reuse - Check if system relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Limit Password Reuse - Ensure authselect custom profile is used if authselect
is present
block:
- name: Limit Password Reuse - Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Limit Password Reuse - Informative message based on the authselect integrity
check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because an authselect profile was
not selected or the selected profile is not intact.
- It is not recommended to manually edit the PAM files when authselect tool
is available.
- In cases where the default authselect profile does not cover a specific
demand, a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Limit Password Reuse - Get authselect current profile
ansible.builtin.shell:
cmd: authselect current -r | awk '{ print $1 }'
register: result_authselect_profile
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Limit Password Reuse - Define the current authselect profile as a local
fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is match("custom/")
- name: Limit Password Reuse - Define the new authselect custom profile as a local
fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: custom/hardening
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is not match("custom/")
- name: Limit Password Reuse - Get authselect current features to also enable
them in the custom profile
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- name: Limit Password Reuse - Check if any custom profile with the same name
was already created
ansible.builtin.stat:
path: /etc/authselect/{{ authselect_custom_profile }}
register: result_authselect_custom_profile_present
changed_when: false
when:
- authselect_current_profile is not match("custom/")
- name: Limit Password Reuse - Create an authselect custom profile based on the
current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Limit Password Reuse - Ensure the authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
register: result_pam_authselect_select_profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Limit Password Reuse - Restore the authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Limit Password Reuse - Change the PAM file to be edited according to the
custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Limit Password Reuse - Check if expected PAM module line is present in {{
pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwhistory.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
- name: Limit Password Reuse - Include or update the PAM module line in {{ pam_file_path
}}
block:
- name: Limit Password Reuse - Check if required PAM module line is present in
{{ pam_file_path }} with different control
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+.*\s+pam_pwhistory.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Limit Password Reuse - Ensure the correct control for the required PAM
module line in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: ^(\s*password\s+).*(\bpam_pwhistory.so.*)
replace: \1requisite \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Limit Password Reuse - Ensure the required PAM module line is included
in {{ pam_file_path }}
ansible.builtin.lineinfile:
dest: '{{ pam_file_path }}'
insertafter: ^password.*requisite.*pam_pwquality\.so
line: password requisite pam_pwhistory.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
when:
- '"pam" in ansible_facts.packages'
- |
(result_authselect_available_features.stdout is defined and result_authselect_available_features.stdout is not search("with-pwhistory")) or result_authselect_available_features is not defined
tags:
- CCE-85678-1
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020250
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Limit Password Reuse - Check the presence of /etc/security/pwhistory.conf
file
ansible.builtin.stat:
path: /etc/security/pwhistory.conf
register: result_pwhistory_conf_check
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85678-1
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020250
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Limit Password Reuse - pam_pwhistory.so parameters are configured in /etc/security/pwhistory.conf
file
block:
- name: Limit Password Reuse - Ensure the pam_pwhistory.so remember parameter in
/etc/security/pwhistory.conf
ansible.builtin.lineinfile:
path: /etc/security/pwhistory.conf
regexp: ^\s*remember\s*=
line: remember = {{ var_password_pam_unix_remember }}
state: present
- name: Limit Password Reuse - Ensure the pam_pwhistory.so remember parameter is
removed from PAM files
block:
- name: Limit Password Reuse - Check if /etc/pam.d/common-password file is present
ansible.builtin.stat:
path: /etc/pam.d/common-password
register: result_pam_file_present
- name: Limit Password Reuse - Check the proper remediation for the system
block:
- name: Limit Password Reuse - Define the PAM file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/common-password
- name: Limit Password Reuse - Check if system relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Limit Password Reuse - Ensure authselect custom profile is used if authselect
is present
block:
- name: Limit Password Reuse - Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Limit Password Reuse - Informative message based on the authselect
integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because an authselect profile
was not selected or the selected profile is not intact.
- It is not recommended to manually edit the PAM files when authselect
tool is available.
- In cases where the default authselect profile does not cover a specific
demand, a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Limit Password Reuse - Get authselect current profile
ansible.builtin.shell:
cmd: authselect current -r | awk '{ print $1 }'
register: result_authselect_profile
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Limit Password Reuse - Define the current authselect profile as a
local fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is match("custom/")
- name: Limit Password Reuse - Define the new authselect custom profile as
a local fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: custom/hardening
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is not match("custom/")
- name: Limit Password Reuse - Get authselect current features to also enable
them in the custom profile
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- name: Limit Password Reuse - Check if any custom profile with the same name
was already created
ansible.builtin.stat:
path: /etc/authselect/{{ authselect_custom_profile }}
register: result_authselect_custom_profile_present
changed_when: false
when:
- authselect_current_profile is not match("custom/")
- name: Limit Password Reuse - Create an authselect custom profile based on
the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Limit Password Reuse - Ensure the authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
register: result_pam_authselect_select_profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Limit Password Reuse - Restore the authselect features in the custom
profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Limit Password Reuse - Change the PAM file to be edited according
to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Limit Password Reuse - Ensure the "remember" option from "pam_pwhistory.so"
is not present in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*password.*pam_pwhistory.so.*)\bremember\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- result_pam_option_removal is changed
when:
- result_pam_file_present.stat.exists
when:
- '"pam" in ansible_facts.packages'
- result_pwhistory_conf_check.stat.exists
tags:
- CCE-85678-1
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020250
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Limit Password Reuse - pam_pwhistory.so parameters are configured in PAM files
block:
- name: Limit Password Reuse - Define the PAM file to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/common-password
- name: Limit Password Reuse - Check if system relies on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Limit Password Reuse - Ensure authselect custom profile is used if authselect
is present
block:
- name: Limit Password Reuse - Check integrity of authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Limit Password Reuse - Informative message based on the authselect integrity
check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because an authselect profile was
not selected or the selected profile is not intact.
- It is not recommended to manually edit the PAM files when authselect tool
is available.
- In cases where the default authselect profile does not cover a specific
demand, a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Limit Password Reuse - Get authselect current profile
ansible.builtin.shell:
cmd: authselect current -r | awk '{ print $1 }'
register: result_authselect_profile
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Limit Password Reuse - Define the current authselect profile as a local
fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is match("custom/")
- name: Limit Password Reuse - Define the new authselect custom profile as a local
fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: custom/hardening
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is not match("custom/")
- name: Limit Password Reuse - Get authselect current features to also enable
them in the custom profile
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- name: Limit Password Reuse - Check if any custom profile with the same name
was already created
ansible.builtin.stat:
path: /etc/authselect/{{ authselect_custom_profile }}
register: result_authselect_custom_profile_present
changed_when: false
when:
- authselect_current_profile is not match("custom/")
- name: Limit Password Reuse - Create an authselect custom profile based on the
current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Limit Password Reuse - Ensure the authselect custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
register: result_pam_authselect_select_profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Limit Password Reuse - Restore the authselect features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Limit Password Reuse - Change the PAM file to be edited according to the
custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Limit Password Reuse - Check if expected PAM module line is present in {{
pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwhistory.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
- name: Limit Password Reuse - Include or update the PAM module line in {{ pam_file_path
}}
block:
- name: Limit Password Reuse - Check if required PAM module line is present in
{{ pam_file_path }} with different control
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+.*\s+pam_pwhistory.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Limit Password Reuse - Ensure the correct control for the required PAM
module line in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: ^(\s*password\s+).*(\bpam_pwhistory.so.*)
replace: \1requisite \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Limit Password Reuse - Ensure the required PAM module line is included
in {{ pam_file_path }}
ansible.builtin.lineinfile:
dest: '{{ pam_file_path }}'
line: password requisite pam_pwhistory.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
- name: Limit Password Reuse - Check if the required PAM module option is present
in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwhistory.so\s*.*\sremember\b
state: absent
check_mode: true
changed_when: false
register: result_pam_module_remember_option_present
- name: Limit Password Reuse - Ensure the "remember" PAM option for "pam_pwhistory.so"
is included in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
backrefs: true
regexp: ^(\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwhistory.so.*)
line: \1 remember={{ var_password_pam_unix_remember }}
state: present
register: result_pam_remember_add
when:
- result_pam_module_remember_option_present.found == 0
- name: Limit Password Reuse - Ensure the required value for "remember" PAM option
from "pam_pwhistory.so" in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
backrefs: true
regexp: ^(\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwhistory.so\s+.*)(remember)=[0-9a-zA-Z]+\s*(.*)
line: \1\2={{ var_password_pam_unix_remember }} \3
register: result_pam_remember_edit
when:
- result_pam_module_remember_option_present.found > 0
- name: Limit Password Reuse - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- (result_pam_remember_add is defined and result_pam_remember_add.changed) or
(result_pam_remember_edit is defined and result_pam_remember_edit.changed)
when:
- '"pam" in ansible_facts.packages'
- not result_pwhistory_conf_check.stat.exists
tags:
- CCE-85678-1
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020250
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.5
- PCI-DSSv4-8.3.7
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_unix_remember='4'
if [ -f /usr/bin/authselect ]; then
if authselect list-features minimal | grep -q with-pwhistory; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
authselect enable-feature with-pwhistory
authselect apply-changes -b
else
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/common-password")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwhistory.so\s*.*' "$PAM_FILE_PATH"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwhistory.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_pwhistory.so.*)/\1'"requisite"' \2/' "$PAM_FILE_PATH"
else
LAST_MATCH_LINE=$(grep -nP "^password.*requisite.*pam_pwquality\.so" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
if [ ! -z $LAST_MATCH_LINE ]; then
sed -i --follow-symlinks $LAST_MATCH_LINE' a password '"requisite"' pam_pwhistory.so' "$PAM_FILE_PATH"
else
echo 'password '"requisite"' pam_pwhistory.so' >> "$PAM_FILE_PATH"
fi
fi
fi
fi
else
if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwhistory.so\s*.*' "/etc/pam.d/common-password"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwhistory.so\s*' "/etc/pam.d/common-password")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_pwhistory.so.*)/\1'"requisite"' \2/' "/etc/pam.d/common-password"
else
LAST_MATCH_LINE=$(grep -nP "^password.*requisite.*pam_pwquality\.so" "/etc/pam.d/common-password" | tail -n 1 | cut -d: -f 1)
if [ ! -z $LAST_MATCH_LINE ]; then
sed -i --follow-symlinks $LAST_MATCH_LINE' a password '"requisite"' pam_pwhistory.so' "/etc/pam.d/common-password"
else
echo 'password '"requisite"' pam_pwhistory.so' >> "/etc/pam.d/common-password"
fi
fi
fi
fi
PWHISTORY_CONF="/etc/security/pwhistory.conf"
if [ -f $PWHISTORY_CONF ]; then
regex="^\s*remember\s*="
line="remember = $var_password_pam_unix_remember"
if ! grep -q $regex $PWHISTORY_CONF; then
echo $line >> $PWHISTORY_CONF
else
sed -i --follow-symlinks 's|^\s*\(remember\s*=\s*\)\(\S\+\)|\1'"$var_password_pam_unix_remember"'|g' $PWHISTORY_CONF
fi
if [ -e "/etc/pam.d/common-password" ] ; then
PAM_FILE_PATH="/etc/pam.d/common-password"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/common-password")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*password\s.*\bpam_pwhistory.so\s.*\bremember\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*password.*pam_pwhistory.so.*)\bremember\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/common-password was not found" >&2
fi
else
PAM_FILE_PATH="/etc/pam.d/common-password"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/common-password")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwhistory.so\s*.*' "$PAM_FILE_PATH"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwhistory.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_pwhistory.so.*)/\1'"requisite"' \2/' "$PAM_FILE_PATH"
else
echo 'password '"requisite"' pam_pwhistory.so' >> "$PAM_FILE_PATH"
fi
fi
# Check the option
if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwhistory.so\s*.*\sremember\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks '/\s*password\s+'"requisite"'\s+pam_pwhistory.so.*/ s/$/ remember='"$var_password_pam_unix_remember"'/' "$PAM_FILE_PATH"
else
sed -i -E --follow-symlinks 's/(\s*password\s+'"requisite"'\s+pam_pwhistory.so\s+.*)('"remember"'=)[[:alnum:]]+\s*(.*)/\1\2'"$var_password_pam_unix_remember"' \3/' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Deny For Failed Password Attempts
[ref]ruleThe SUSE Linux Enterprise 15 operating system must lock an account after - at most - 10
consecutive invalid access attempts. Rationale:By limiting the number of failed logon attempts, the risk of unauthorized
system access via user password guessing, otherwise known as brute-force
attacks, is reduced. Limits are imposed by locking the account.
To configure the operating system to lock an account after three
unsuccessful consecutive access attempts using pam_tally2.so ,
modify the content of both /etc/pam.d/login and
/etc/pam.d/common-account as follows:
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: XCCDF Value var_password_pam_tally2 # promote to variable
set_fact:
var_password_pam_tally2: !!str 10
tags:
- always
- name: Set Deny For Failed Password Attempts - Check if expected PAM module line
is present in /etc/pam.d/login
ansible.builtin.lineinfile:
path: /etc/pam.d/login
regexp: ^\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Include or update the PAM module line
in /etc/pam.d/login
block:
- name: Set Deny For Failed Password Attempts - Check if required PAM module line
is present in /etc/pam.d/login with different control
ansible.builtin.lineinfile:
path: /etc/pam.d/login
regexp: ^\s*auth\s+.*\s+pam_tally2.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Set Deny For Failed Password Attempts - Ensure the correct control for the
required PAM module line in /etc/pam.d/login
ansible.builtin.replace:
dest: /etc/pam.d/login
regexp: ^(\s*auth\s+).*(\bpam_tally2.so.*)
replace: \1required \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Set Deny For Failed Password Attempts - Ensure the required PAM module line
is included in /etc/pam.d/login
ansible.builtin.lineinfile:
dest: /etc/pam.d/login
line: auth required pam_tally2.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Set Deny For Failed Password Attempts - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- '"pam" in ansible_facts.packages'
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Check if the required PAM module option
is present in /etc/pam.d/login
ansible.builtin.lineinfile:
path: /etc/pam.d/login
regexp: ^\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*\sdeny\b
state: absent
check_mode: true
changed_when: false
register: result_pam_module_deny_option_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Ensure the "deny" PAM option for "pam_tally2.so"
is included in /etc/pam.d/login
ansible.builtin.lineinfile:
path: /etc/pam.d/login
backrefs: true
regexp: ^(\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so.*)
line: \1 deny={{ var_password_pam_tally2 }}
state: present
register: result_pam_deny_add
when:
- '"pam" in ansible_facts.packages'
- result_pam_module_deny_option_present.found == 0
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Ensure the required value for "deny"
PAM option from "pam_tally2.so" in /etc/pam.d/login
ansible.builtin.lineinfile:
path: /etc/pam.d/login
backrefs: true
regexp: ^(\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s+.*)(deny)=[0-9a-zA-Z]+\s*(.*)
line: \1\2={{ var_password_pam_tally2 }} \3
register: result_pam_deny_edit
when:
- '"pam" in ansible_facts.packages'
- result_pam_module_deny_option_present.found > 0
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Check if expected PAM module line
is present in /etc/pam.d/login
ansible.builtin.lineinfile:
path: /etc/pam.d/login
regexp: ^\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Include or update the PAM module line
in /etc/pam.d/login
block:
- name: Set Deny For Failed Password Attempts - Check if required PAM module line
is present in /etc/pam.d/login with different control
ansible.builtin.lineinfile:
path: /etc/pam.d/login
regexp: ^\s*auth\s+.*\s+pam_tally2.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Set Deny For Failed Password Attempts - Ensure the correct control for the
required PAM module line in /etc/pam.d/login
ansible.builtin.replace:
dest: /etc/pam.d/login
regexp: ^(\s*auth\s+).*(\bpam_tally2.so.*)
replace: \1required \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Set Deny For Failed Password Attempts - Ensure the required PAM module line
is included in /etc/pam.d/login
ansible.builtin.lineinfile:
dest: /etc/pam.d/login
insertafter: (fail)
line: auth required pam_tally2.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Set Deny For Failed Password Attempts - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- '"pam" in ansible_facts.packages'
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Check if the required PAM module option
is present in /etc/pam.d/login
ansible.builtin.lineinfile:
path: /etc/pam.d/login
regexp: ^\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*\sonerr\b
state: absent
check_mode: true
changed_when: false
register: result_pam_module_onerr_option_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Ensure the "onerr" PAM option for
"pam_tally2.so" is included in /etc/pam.d/login
ansible.builtin.lineinfile:
path: /etc/pam.d/login
backrefs: true
regexp: ^(\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so.*)
line: \1 onerr=fail
state: present
register: result_pam_onerr_add
when:
- '"pam" in ansible_facts.packages'
- result_pam_module_onerr_option_present.found == 0
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Ensure the required value for "onerr"
PAM option from "pam_tally2.so" in /etc/pam.d/login
ansible.builtin.lineinfile:
path: /etc/pam.d/login
backrefs: true
regexp: ^(\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s+.*)(onerr)=[0-9a-zA-Z]+\s*(.*)
line: \1\2=fail \3
register: result_pam_onerr_edit
when:
- '"pam" in ansible_facts.packages'
- result_pam_module_onerr_option_present.found > 0
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Check if expected PAM module line
is present in /etc/pam.d/common-account
ansible.builtin.lineinfile:
path: /etc/pam.d/common-account
regexp: ^\s*account\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Include or update the PAM module line
in /etc/pam.d/common-account
block:
- name: Set Deny For Failed Password Attempts - Check if required PAM module line
is present in /etc/pam.d/common-account with different control
ansible.builtin.lineinfile:
path: /etc/pam.d/common-account
regexp: ^\s*account\s+.*\s+pam_tally2.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Set Deny For Failed Password Attempts - Ensure the correct control for the
required PAM module line in /etc/pam.d/common-account
ansible.builtin.replace:
dest: /etc/pam.d/common-account
regexp: ^(\s*account\s+).*(\bpam_tally2.so.*)
replace: \1required \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Set Deny For Failed Password Attempts - Ensure the required PAM module line
is included in /etc/pam.d/common-account
ansible.builtin.lineinfile:
dest: /etc/pam.d/common-account
line: account required pam_tally2.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Set Deny For Failed Password Attempts - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- '"pam" in ansible_facts.packages'
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Check if the required PAM module option
is present in /etc/pam.d/common-account
ansible.builtin.lineinfile:
path: /etc/pam.d/common-account
regexp: ^\s*account\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*\s\b
state: absent
check_mode: true
changed_when: false
register: result_pam_module__option_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Deny For Failed Password Attempts - Ensure the "" PAM option for "pam_tally2.so"
is included in /etc/pam.d/common-account
ansible.builtin.lineinfile:
path: /etc/pam.d/common-account
backrefs: true
regexp: ^(\s*account\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so.*)
line: \1
state: present
register: result_pam__add
when:
- '"pam" in ansible_facts.packages'
- result_pam_module__option_present.found == 0
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- PCI-DSS-Req-8.1.6
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_password_pam_tally2='10'
# Use a non-number regexp to force update of the value of the deny option
if ! grep -qP '^\s*auth\s+'"required"'\s+pam_tally2.so\s*.*' "/etc/pam.d/login"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*auth\s+.*\s+pam_tally2.so\s*' "/etc/pam.d/login")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*auth\s+).*(\bpam_tally2.so.*)/\1'"required"' \2/' "/etc/pam.d/login"
else
echo 'auth '"required"' pam_tally2.so' >> "/etc/pam.d/login"
fi
fi
# Check the option
if ! grep -qP '^\s*auth\s+'"required"'\s+pam_tally2.so\s*.*\sdeny\b' "/etc/pam.d/login"; then
sed -i -E --follow-symlinks '/\s*auth\s+'"required"'\s+pam_tally2.so.*/ s/$/ deny='"${var_password_pam_tally2}"'/' "/etc/pam.d/login"
else
sed -i -E --follow-symlinks 's/(\s*auth\s+'"required"'\s+pam_tally2.so\s+.*)('"deny"'=)[[:alnum:]]+\s*(.*)/\1\2'"${var_password_pam_tally2}"' \3/' "/etc/pam.d/login"
fi
if ! grep -qP '^\s*auth\s+'"required"'\s+pam_tally2.so\s*.*' "/etc/pam.d/login"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*auth\s+.*\s+pam_tally2.so\s*' "/etc/pam.d/login")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*auth\s+).*(\bpam_tally2.so.*)/\1'"required"' \2/' "/etc/pam.d/login"
else
LAST_MATCH_LINE=$(grep -nP "(fail)" "/etc/pam.d/login" | tail -n 1 | cut -d: -f 1)
if [ ! -z $LAST_MATCH_LINE ]; then
sed -i --follow-symlinks $LAST_MATCH_LINE' a auth '"required"' pam_tally2.so' "/etc/pam.d/login"
else
echo 'auth '"required"' pam_tally2.so' >> "/etc/pam.d/login"
fi
fi
fi
# Check the option
if ! grep -qP '^\s*auth\s+'"required"'\s+pam_tally2.so\s*.*\sonerr\b' "/etc/pam.d/login"; then
sed -i -E --follow-symlinks '/\s*auth\s+'"required"'\s+pam_tally2.so.*/ s/$/ onerr='"fail"'/' "/etc/pam.d/login"
else
sed -i -E --follow-symlinks 's/(\s*auth\s+'"required"'\s+pam_tally2.so\s+.*)('"onerr"'=)[[:alnum:]]+\s*(.*)/\1\2'"fail"' \3/' "/etc/pam.d/login"
fi
if ! grep -qP '^\s*account\s+'"required"'\s+pam_tally2.so\s*.*' "/etc/pam.d/common-account"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*account\s+.*\s+pam_tally2.so\s*' "/etc/pam.d/common-account")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*account\s+).*(\bpam_tally2.so.*)/\1'"required"' \2/' "/etc/pam.d/common-account"
else
echo 'account '"required"' pam_tally2.so' >> "/etc/pam.d/common-account"
fi
fi
# Check the option
if ! grep -qP '^\s*account\s+'"required"'\s+pam_tally2.so\s*.*\s\b' "/etc/pam.d/common-account"; then
sed -i -E --follow-symlinks '/\s*account\s+'"required"'\s+pam_tally2.so.*/ s/$/ /' "/etc/pam.d/common-account"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Lockout Time for Failed Password Attempts using pam_tally2
[ref]ruleThis rule configures the system to lock out accounts during a specified time period after a
number of incorrect login attempts using pam_tally2.so . Rationale:By limiting the number of failed logon attempts, the risk of unauthorized system access via
user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking
the account. Identifiers:
CCE-91282-4 References:
BP28(R18), 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, CCI-002238, CCI-000044, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-7(b), IA-5(c), PR.AC-7, FMT_MOF_EXT.1, Req-8.1.7, 8.3.4, SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005, 5.3.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-91282-4
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_passwords_pam_tally2_unlock_time # promote to variable
set_fact:
var_accounts_passwords_pam_tally2_unlock_time: !!str 1800
tags:
- always
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Check if
expected PAM module line is present in /etc/pam.d/login
ansible.builtin.lineinfile:
path: /etc/pam.d/login
regexp: ^\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-91282-4
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Include or
update the PAM module line in /etc/pam.d/login
block:
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Check if
required PAM module line is present in /etc/pam.d/login with different control
ansible.builtin.lineinfile:
path: /etc/pam.d/login
regexp: ^\s*auth\s+.*\s+pam_tally2.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Ensure
the correct control for the required PAM module line in /etc/pam.d/login
ansible.builtin.replace:
dest: /etc/pam.d/login
regexp: ^(\s*auth\s+).*(\bpam_tally2.so.*)
replace: \1required \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Ensure
the required PAM module line is included in /etc/pam.d/login
ansible.builtin.lineinfile:
dest: /etc/pam.d/login
line: auth required pam_tally2.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Ensure
authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- '"pam" in ansible_facts.packages'
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
tags:
- CCE-91282-4
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Check if
the required PAM module option is present in /etc/pam.d/login
ansible.builtin.lineinfile:
path: /etc/pam.d/login
regexp: ^\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*\sunlock_time\b
state: absent
check_mode: true
changed_when: false
register: result_pam_module_unlock_time_option_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-91282-4
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Ensure the
"unlock_time" PAM option for "pam_tally2.so" is included in /etc/pam.d/login
ansible.builtin.lineinfile:
path: /etc/pam.d/login
backrefs: true
regexp: ^(\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so.*)
line: \1 unlock_time={{var_accounts_passwords_pam_tally2_unlock_time}}
state: present
register: result_pam_unlock_time_add
when:
- '"pam" in ansible_facts.packages'
- result_pam_module_unlock_time_option_present.found == 0
tags:
- CCE-91282-4
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Ensure the
required value for "unlock_time" PAM option from "pam_tally2.so" in /etc/pam.d/login
ansible.builtin.lineinfile:
path: /etc/pam.d/login
backrefs: true
regexp: ^(\s*auth\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s+.*)(unlock_time)=[0-9a-zA-Z]+\s*(.*)
line: \1\2={{var_accounts_passwords_pam_tally2_unlock_time}} \3
register: result_pam_unlock_time_edit
when:
- '"pam" in ansible_facts.packages'
- result_pam_module_unlock_time_option_present.found > 0
tags:
- CCE-91282-4
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Check if
expected PAM module line is present in /etc/pam.d/common-account
ansible.builtin.lineinfile:
path: /etc/pam.d/common-account
regexp: ^\s*account\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-91282-4
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Include or
update the PAM module line in /etc/pam.d/common-account
block:
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Check if
required PAM module line is present in /etc/pam.d/common-account with different
control
ansible.builtin.lineinfile:
path: /etc/pam.d/common-account
regexp: ^\s*account\s+.*\s+pam_tally2.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Ensure
the correct control for the required PAM module line in /etc/pam.d/common-account
ansible.builtin.replace:
dest: /etc/pam.d/common-account
regexp: ^(\s*account\s+).*(\bpam_tally2.so.*)
replace: \1required \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Ensure
the required PAM module line is included in /etc/pam.d/common-account
ansible.builtin.lineinfile:
dest: /etc/pam.d/common-account
line: account required pam_tally2.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Ensure
authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- '"pam" in ansible_facts.packages'
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
tags:
- CCE-91282-4
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Check if
the required PAM module option is present in /etc/pam.d/common-account
ansible.builtin.lineinfile:
path: /etc/pam.d/common-account
regexp: ^\s*account\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so\s*.*\s\b
state: absent
check_mode: true
changed_when: false
register: result_pam_module__option_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-91282-4
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Lockout Time for Failed Password Attempts using pam_tally2 - Ensure the
"" PAM option for "pam_tally2.so" is included in /etc/pam.d/common-account
ansible.builtin.lineinfile:
path: /etc/pam.d/common-account
backrefs: true
regexp: ^(\s*account\s+{{ 'required' | regex_escape() }}\s+pam_tally2.so.*)
line: \1
state: present
register: result_pam__add
when:
- '"pam" in ansible_facts.packages'
- result_pam_module__option_present.found == 0
tags:
- CCE-91282-4
- NIST-800-53-AC-7(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- accounts_passwords_pam_tally2_unlock_time
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_accounts_passwords_pam_tally2_unlock_time='1800'
# Use a non-number regexp to force update of the value of the deny option
if ! grep -qP '^\s*auth\s+'"required"'\s+pam_tally2.so\s*.*' "/etc/pam.d/login"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*auth\s+.*\s+pam_tally2.so\s*' "/etc/pam.d/login")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*auth\s+).*(\bpam_tally2.so.*)/\1'"required"' \2/' "/etc/pam.d/login"
else
echo 'auth '"required"' pam_tally2.so' >> "/etc/pam.d/login"
fi
fi
# Check the option
if ! grep -qP '^\s*auth\s+'"required"'\s+pam_tally2.so\s*.*\sunlock_time\b' "/etc/pam.d/login"; then
sed -i -E --follow-symlinks '/\s*auth\s+'"required"'\s+pam_tally2.so.*/ s/$/ unlock_time='"${var_accounts_passwords_pam_tally2_unlock_time}"'/' "/etc/pam.d/login"
else
sed -i -E --follow-symlinks 's/(\s*auth\s+'"required"'\s+pam_tally2.so\s+.*)('"unlock_time"'=)[[:alnum:]]+\s*(.*)/\1\2'"${var_accounts_passwords_pam_tally2_unlock_time}"' \3/' "/etc/pam.d/login"
fi
if ! grep -qP '^\s*account\s+'"required"'\s+pam_tally2.so\s*.*' "/etc/pam.d/common-account"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*account\s+.*\s+pam_tally2.so\s*' "/etc/pam.d/common-account")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*account\s+).*(\bpam_tally2.so.*)/\1'"required"' \2/' "/etc/pam.d/common-account"
else
echo 'account '"required"' pam_tally2.so' >> "/etc/pam.d/common-account"
fi
fi
# Check the option
if ! grep -qP '^\s*account\s+'"required"'\s+pam_tally2.so\s*.*\s\b' "/etc/pam.d/common-account"; then
sed -i -E --follow-symlinks '/\s*account\s+'"required"'\s+pam_tally2.so.*/ s/$/ /' "/etc/pam.d/common-account"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Password Quality Requirements
[ref]groupThe default pam_pwquality PAM module provides strength
checking for passwords. It performs a number of checks, such as
making sure passwords are not similar to dictionary words, are of
at least a certain length, are not the previous password reversed,
and are not simply a change of case from the previous password. It
can also require passwords to be in certain character classes. The
pam_pwquality module is the preferred way of configuring
password requirements.
The man pages pam_pwquality(8)
provide information on the capabilities and configuration of
each. |
contains 4 rules |
Set Password Quality Requirements, if using
pam_cracklib
[ref]groupThe pam_cracklib PAM module can be configured to meet
requirements for a variety of policies.
For example, to configure pam_cracklib to require at least one uppercase
character, lowercase character, digit, and other (special)
character, locate the following line in /etc/pam.d/system-auth :
password requisite pam_cracklib.so try_first_pass retry=3
and then alter it to read:
password required pam_cracklib.so try_first_pass retry=3 maxrepeat=3 minlen=14 dcredit=-1 ucredit=-1 ocredit=-1 lcredit=-1 difok=4
If no such line exists, add one as the first line of the password section in /etc/pam.d/system-auth .
The arguments can be modified to ensure compliance with
your organization's security policy. Discussion of each parameter follows.Warning:
Note that the password quality requirements are not enforced for the
root account for some reason. |
contains 4 rules |
Set Password Strength Minimum Digit Characters
[ref]ruleThe pam_cracklib module's dcredit parameter controls requirements
for usage of digits in a password. When set to a negative number, any
password will be required to contain that many digits. When set to a
positive number, pam_cracklib will grant +1 additional length credit for
each digit. Add dcredit=-1 after pam_cracklib.so to require use of
a digit in passwords. Rationale:Requiring digits makes password guessing attacks more difficult by ensuring
a larger search space. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_password_pam_dcredit # promote to variable
set_fact:
var_password_pam_dcredit: !!str -1
tags:
- always
- name: Set control_flag fact
set_fact:
control_flag: requisite
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check to see if 'pam_cracklib.so' module is configured in '/etc/pam.d/common-password'
shell: |
set -o pipefail
grep -E '^\s*password\s+\S+\s+pam_cracklib.so' /etc/pam.d/common-password || true
register: check_pam_module_result
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure 'pam_cracklib.so' module in '/etc/pam.d/common-password'
lineinfile:
path: /etc/pam.d/common-password
line: password requisite pam_cracklib.so
state: present
when: '"pam_cracklib.so" not in check_pam_module_result.stdout'
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure 'pam_cracklib.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+)\S+(\s+pam_cracklib.so\s+.*)
line: \g<1>requisite\g<2>
backrefs: true
when: control_flag|length
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure "pam_cracklib.so" module has argument "dcredit={{ var_password_pam_dcredit
}}"
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so(?:\s+\S+)*\s+dcredit=)(?:\S+)((\s+\S+)*\s*\\*\s*)$
line: \g<1>{{ var_password_pam_dcredit }}\g<2>
backrefs: true
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the presence of "dcredit" argument in "pam_cracklib.so" module
shell: |
set -o pipefail
grep -E '^\s*password\s+requisite\s+pam_cracklib.so.*\s+dcredit(=|\s|\s*$)' /etc/pam.d/common-password || true
register: check_pam_module_argument_result
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add "dcredit" argument to "pam_cracklib.so" module
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> dcredit={{ var_password_pam_dcredit }}\g<2>
backrefs: true
when: '"dcredit" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
declare -a VALUES=()
declare -a VALUE_NAMES=()
declare -a ARGS=()
declare -a NEW_ARGS=()
var_password_pam_dcredit='-1'
VALUES+=("$var_password_pam_dcredit")
VALUE_NAMES+=("dcredit")
ARGS+=("")
NEW_ARGS+=("")
for idx in "${!VALUES[@]}"
do
if [ -e "/etc/pam.d/common-password" ] ; then
valueRegex="${VALUES[$idx]}" defaultValue="${VALUES[$idx]}"
# non-empty values need to be preceded by an equals sign
[ -n "${valueRegex}" ] && valueRegex="=${valueRegex}"
# add an equals sign to non-empty values
[ -n "${defaultValue}" ] && defaultValue="=${defaultValue}"
# fix the value for 'option' if one exists but does not match 'valueRegex'
if grep -q -P "^\\s*password\\s+requisite\\s+pam_cracklib.so(\\s.+)?\\s+${VALUE_NAMES[$idx]}(?"'!'"${valueRegex}(\\s|\$))" < "/etc/pam.d/common-password" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+requisite\\s+pam_cracklib.so(\\s.+)?\\s)${VALUE_NAMES[$idx]}=[^[:space:]]*/\\1${VALUE_NAMES[$idx]}${defaultValue}/" "/etc/pam.d/common-password"
# add 'option=default' if option is not set
elif grep -q -E "^\\s*password\\s+requisite\\s+pam_cracklib.so" < "/etc/pam.d/common-password" &&
grep -E "^\\s*password\\s+requisite\\s+pam_cracklib.so" < "/etc/pam.d/common-password" | grep -q -E -v "\\s${VALUE_NAMES[$idx]}(=|\\s|\$)" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+requisite\\s+pam_cracklib.so[^\\n]*)/\\1 ${VALUE_NAMES[$idx]}${defaultValue}/" "/etc/pam.d/common-password"
# add a new entry if none exists
elif ! grep -q -P "^\\s*password\\s+requisite\\s+pam_cracklib.so(\\s.+)?\\s+${VALUE_NAMES[$idx]}${valueRegex}(\\s|\$)" < "/etc/pam.d/common-password" ; then
echo "password requisite pam_cracklib.so ${VALUE_NAMES[$idx]}${defaultValue}" >> "/etc/pam.d/common-password"
fi
else
echo "/etc/pam.d/common-password doesn't exist" >&2
fi
done
for idx in "${!ARGS[@]}"
do
if ! grep -q -P "^\s*password\s+requisite\s+pam_cracklib.so.*\s+${ARGS[$idx]}\s*$" /etc/pam.d/common-password ; then
sed --follow-symlinks -i -E -e "s/^\\s*password\\s+requisite\\s+pam_cracklib.so.*\$/& ${NEW_ARGS[$idx]}/" /etc/pam.d/common-password
fi
done
|
Set Password Strength Minimum Lowercase Characters
[ref]ruleThe pam_cracklib module's lcredit= parameter controls requirements
for usage of lowercase letters in a password. When set to a negative
number, any password will be required to contain that many lowercase
characters. When set to a positive number, pam_cracklib will grant +1
additional length credit for each lowercase character.
Add lcredit=-1 after pam_cracklib.so to require use of a
lowercase character in passwords. Rationale:Requiring a minimum number of lowercase characters makes password guessing
attacks more difficult by ensuring a larger search space. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_password_pam_lcredit # promote to variable
set_fact:
var_password_pam_lcredit: !!str -1
tags:
- always
- name: Set control_flag fact
set_fact:
control_flag: requisite
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check to see if 'pam_cracklib.so' module is configured in '/etc/pam.d/common-password'
shell: |
set -o pipefail
grep -E '^\s*password\s+\S+\s+pam_cracklib.so' /etc/pam.d/common-password || true
register: check_pam_module_result
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure 'pam_cracklib.so' module in '/etc/pam.d/common-password'
lineinfile:
path: /etc/pam.d/common-password
line: password requisite pam_cracklib.so
state: present
when: '"pam_cracklib.so" not in check_pam_module_result.stdout'
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure 'pam_cracklib.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+)\S+(\s+pam_cracklib.so\s+.*)
line: \g<1>requisite\g<2>
backrefs: true
when: control_flag|length
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure "pam_cracklib.so" module has argument "lcredit={{ var_password_pam_lcredit
}}"
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so(?:\s+\S+)*\s+lcredit=)(?:\S+)((\s+\S+)*\s*\\*\s*)$
line: \g<1>{{ var_password_pam_lcredit }}\g<2>
backrefs: true
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the presence of "lcredit" argument in "pam_cracklib.so" module
shell: |
set -o pipefail
grep -E '^\s*password\s+requisite\s+pam_cracklib.so.*\s+lcredit(=|\s|\s*$)' /etc/pam.d/common-password || true
register: check_pam_module_argument_result
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add "lcredit" argument to "pam_cracklib.so" module
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> lcredit={{ var_password_pam_lcredit }}\g<2>
backrefs: true
when: '"lcredit" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
declare -a VALUES=()
declare -a VALUE_NAMES=()
declare -a ARGS=()
declare -a NEW_ARGS=()
var_password_pam_lcredit='-1'
VALUES+=("$var_password_pam_lcredit")
VALUE_NAMES+=("lcredit")
ARGS+=("")
NEW_ARGS+=("")
for idx in "${!VALUES[@]}"
do
if [ -e "/etc/pam.d/common-password" ] ; then
valueRegex="${VALUES[$idx]}" defaultValue="${VALUES[$idx]}"
# non-empty values need to be preceded by an equals sign
[ -n "${valueRegex}" ] && valueRegex="=${valueRegex}"
# add an equals sign to non-empty values
[ -n "${defaultValue}" ] && defaultValue="=${defaultValue}"
# fix the value for 'option' if one exists but does not match 'valueRegex'
if grep -q -P "^\\s*password\\s+requisite\\s+pam_cracklib.so(\\s.+)?\\s+${VALUE_NAMES[$idx]}(?"'!'"${valueRegex}(\\s|\$))" < "/etc/pam.d/common-password" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+requisite\\s+pam_cracklib.so(\\s.+)?\\s)${VALUE_NAMES[$idx]}=[^[:space:]]*/\\1${VALUE_NAMES[$idx]}${defaultValue}/" "/etc/pam.d/common-password"
# add 'option=default' if option is not set
elif grep -q -E "^\\s*password\\s+requisite\\s+pam_cracklib.so" < "/etc/pam.d/common-password" &&
grep -E "^\\s*password\\s+requisite\\s+pam_cracklib.so" < "/etc/pam.d/common-password" | grep -q -E -v "\\s${VALUE_NAMES[$idx]}(=|\\s|\$)" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+requisite\\s+pam_cracklib.so[^\\n]*)/\\1 ${VALUE_NAMES[$idx]}${defaultValue}/" "/etc/pam.d/common-password"
# add a new entry if none exists
elif ! grep -q -P "^\\s*password\\s+requisite\\s+pam_cracklib.so(\\s.+)?\\s+${VALUE_NAMES[$idx]}${valueRegex}(\\s|\$)" < "/etc/pam.d/common-password" ; then
echo "password requisite pam_cracklib.so ${VALUE_NAMES[$idx]}${defaultValue}" >> "/etc/pam.d/common-password"
fi
else
echo "/etc/pam.d/common-password doesn't exist" >&2
fi
done
for idx in "${!ARGS[@]}"
do
if ! grep -q -P "^\s*password\s+requisite\s+pam_cracklib.so.*\s+${ARGS[$idx]}\s*$" /etc/pam.d/common-password ; then
sed --follow-symlinks -i -E -e "s/^\\s*password\\s+requisite\\s+pam_cracklib.so.*\$/& ${NEW_ARGS[$idx]}/" /etc/pam.d/common-password
fi
done
|
Set Password Minimum Length
[ref]ruleThe pam_cracklib module's minlen parameter controls requirements for
minimum characters required in a password. Add minlen=12
to set minimum password length requirements. Rationale:Password length is one factor of several that helps to determine
strength and how long it takes to crack a password. Use of more characters in
a password helps to exponentially increase the time and/or resources
required to compromise the password. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_password_pam_minlen # promote to variable
set_fact:
var_password_pam_minlen: !!str 12
tags:
- always
- name: Set control_flag fact
set_fact:
control_flag: requisite
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check to see if 'pam_cracklib.so' module is configured in '/etc/pam.d/common-password'
shell: |
set -o pipefail
grep -E '^\s*password\s+\S+\s+pam_cracklib.so' /etc/pam.d/common-password || true
register: check_pam_module_result
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure 'pam_cracklib.so' module in '/etc/pam.d/common-password'
lineinfile:
path: /etc/pam.d/common-password
line: password requisite pam_cracklib.so
state: present
when: '"pam_cracklib.so" not in check_pam_module_result.stdout'
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure 'pam_cracklib.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+)\S+(\s+pam_cracklib.so\s+.*)
line: \g<1>requisite\g<2>
backrefs: true
when: control_flag|length
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure "pam_cracklib.so" module has argument "minlen={{ var_password_pam_minlen
}}"
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so(?:\s+\S+)*\s+minlen=)(?:\S+)((\s+\S+)*\s*\\*\s*)$
line: \g<1>{{ var_password_pam_minlen }}\g<2>
backrefs: true
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the presence of "minlen" argument in "pam_cracklib.so" module
shell: |
set -o pipefail
grep -E '^\s*password\s+requisite\s+pam_cracklib.so.*\s+minlen(=|\s|\s*$)' /etc/pam.d/common-password || true
register: check_pam_module_argument_result
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add "minlen" argument to "pam_cracklib.so" module
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> minlen={{ var_password_pam_minlen }}\g<2>
backrefs: true
when: '"minlen" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.6
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
declare -a VALUES=()
declare -a VALUE_NAMES=()
declare -a ARGS=()
declare -a NEW_ARGS=()
var_password_pam_minlen='12'
VALUES+=("$var_password_pam_minlen")
VALUE_NAMES+=("minlen")
ARGS+=("")
NEW_ARGS+=("")
for idx in "${!VALUES[@]}"
do
if [ -e "/etc/pam.d/common-password" ] ; then
valueRegex="${VALUES[$idx]}" defaultValue="${VALUES[$idx]}"
# non-empty values need to be preceded by an equals sign
[ -n "${valueRegex}" ] && valueRegex="=${valueRegex}"
# add an equals sign to non-empty values
[ -n "${defaultValue}" ] && defaultValue="=${defaultValue}"
# fix the value for 'option' if one exists but does not match 'valueRegex'
if grep -q -P "^\\s*password\\s+requisite\\s+pam_cracklib.so(\\s.+)?\\s+${VALUE_NAMES[$idx]}(?"'!'"${valueRegex}(\\s|\$))" < "/etc/pam.d/common-password" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+requisite\\s+pam_cracklib.so(\\s.+)?\\s)${VALUE_NAMES[$idx]}=[^[:space:]]*/\\1${VALUE_NAMES[$idx]}${defaultValue}/" "/etc/pam.d/common-password"
# add 'option=default' if option is not set
elif grep -q -E "^\\s*password\\s+requisite\\s+pam_cracklib.so" < "/etc/pam.d/common-password" &&
grep -E "^\\s*password\\s+requisite\\s+pam_cracklib.so" < "/etc/pam.d/common-password" | grep -q -E -v "\\s${VALUE_NAMES[$idx]}(=|\\s|\$)" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+requisite\\s+pam_cracklib.so[^\\n]*)/\\1 ${VALUE_NAMES[$idx]}${defaultValue}/" "/etc/pam.d/common-password"
# add a new entry if none exists
elif ! grep -q -P "^\\s*password\\s+requisite\\s+pam_cracklib.so(\\s.+)?\\s+${VALUE_NAMES[$idx]}${valueRegex}(\\s|\$)" < "/etc/pam.d/common-password" ; then
echo "password requisite pam_cracklib.so ${VALUE_NAMES[$idx]}${defaultValue}" >> "/etc/pam.d/common-password"
fi
else
echo "/etc/pam.d/common-password doesn't exist" >&2
fi
done
for idx in "${!ARGS[@]}"
do
if ! grep -q -P "^\s*password\s+requisite\s+pam_cracklib.so.*\s+${ARGS[$idx]}\s*$" /etc/pam.d/common-password ; then
sed --follow-symlinks -i -E -e "s/^\\s*password\\s+requisite\\s+pam_cracklib.so.*\$/& ${NEW_ARGS[$idx]}/" /etc/pam.d/common-password
fi
done
|
Set Password Retry Limit
[ref]ruleThe pam_cracklib module's retry parameter controls the maximum
number of times to prompt the user for the password before returning
with error. Make sure it is configured with a value that is no more than
3. For example, retry=1 . Rationale:To reduce opportunities for successful guesses and brute-force attacks. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_password_pam_retry # promote to variable
set_fact:
var_password_pam_retry: !!str 3
tags:
- always
- name: Set control_flag fact
set_fact:
control_flag: requisite
tags:
- CCE-85575-9
- DISA-STIG-SLES-15-020290
- PCI-DSS-Req-8.1.6
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- cracklib_accounts_password_pam_retry
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check to see if 'pam_cracklib.so' module is configured in '/etc/pam.d/common-password'
shell: |
set -o pipefail
grep -E '^\s*password\s+\S+\s+pam_cracklib.so' /etc/pam.d/common-password || true
register: check_pam_module_result
tags:
- CCE-85575-9
- DISA-STIG-SLES-15-020290
- PCI-DSS-Req-8.1.6
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- cracklib_accounts_password_pam_retry
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure 'pam_cracklib.so' module in '/etc/pam.d/common-password'
lineinfile:
path: /etc/pam.d/common-password
line: password requisite pam_cracklib.so
state: present
when: '"pam_cracklib.so" not in check_pam_module_result.stdout'
tags:
- CCE-85575-9
- DISA-STIG-SLES-15-020290
- PCI-DSS-Req-8.1.6
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- cracklib_accounts_password_pam_retry
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure 'pam_cracklib.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+)\S+(\s+pam_cracklib.so\s+.*)
line: \g<1>requisite\g<2>
backrefs: true
when: control_flag|length
tags:
- CCE-85575-9
- DISA-STIG-SLES-15-020290
- PCI-DSS-Req-8.1.6
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- cracklib_accounts_password_pam_retry
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure "pam_cracklib.so" module has argument "retry={{ var_password_pam_retry
}}"
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so(?:\s+\S+)*\s+retry=)(?:\S+)((\s+\S+)*\s*\\*\s*)$
line: \g<1>{{ var_password_pam_retry }}\g<2>
backrefs: true
tags:
- CCE-85575-9
- DISA-STIG-SLES-15-020290
- PCI-DSS-Req-8.1.6
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- cracklib_accounts_password_pam_retry
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the presence of "retry" argument in "pam_cracklib.so" module
shell: |
set -o pipefail
grep -E '^\s*password\s+requisite\s+pam_cracklib.so.*\s+retry(=|\s|\s*$)' /etc/pam.d/common-password || true
register: check_pam_module_argument_result
tags:
- CCE-85575-9
- DISA-STIG-SLES-15-020290
- PCI-DSS-Req-8.1.6
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- cracklib_accounts_password_pam_retry
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add "retry" argument to "pam_cracklib.so" module
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> retry={{ var_password_pam_retry }}\g<2>
backrefs: true
when: '"retry" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85575-9
- DISA-STIG-SLES-15-020290
- PCI-DSS-Req-8.1.6
- PCI-DSS-Req-8.1.7
- PCI-DSSv4-8.3.4
- cracklib_accounts_password_pam_retry
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
declare -a VALUES=()
declare -a VALUE_NAMES=()
declare -a ARGS=()
declare -a NEW_ARGS=()
var_password_pam_retry='3'
VALUES+=("$var_password_pam_retry")
VALUE_NAMES+=("retry")
ARGS+=("")
NEW_ARGS+=("")
for idx in "${!VALUES[@]}"
do
if [ -e "/etc/pam.d/common-password" ] ; then
valueRegex="${VALUES[$idx]}" defaultValue="${VALUES[$idx]}"
# non-empty values need to be preceded by an equals sign
[ -n "${valueRegex}" ] && valueRegex="=${valueRegex}"
# add an equals sign to non-empty values
[ -n "${defaultValue}" ] && defaultValue="=${defaultValue}"
# fix the value for 'option' if one exists but does not match 'valueRegex'
if grep -q -P "^\\s*password\\s+requisite\\s+pam_cracklib.so(\\s.+)?\\s+${VALUE_NAMES[$idx]}(?"'!'"${valueRegex}(\\s|\$))" < "/etc/pam.d/common-password" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+requisite\\s+pam_cracklib.so(\\s.+)?\\s)${VALUE_NAMES[$idx]}=[^[:space:]]*/\\1${VALUE_NAMES[$idx]}${defaultValue}/" "/etc/pam.d/common-password"
# add 'option=default' if option is not set
elif grep -q -E "^\\s*password\\s+requisite\\s+pam_cracklib.so" < "/etc/pam.d/common-password" &&
grep -E "^\\s*password\\s+requisite\\s+pam_cracklib.so" < "/etc/pam.d/common-password" | grep -q -E -v "\\s${VALUE_NAMES[$idx]}(=|\\s|\$)" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+requisite\\s+pam_cracklib.so[^\\n]*)/\\1 ${VALUE_NAMES[$idx]}${defaultValue}/" "/etc/pam.d/common-password"
# add a new entry if none exists
elif ! grep -q -P "^\\s*password\\s+requisite\\s+pam_cracklib.so(\\s.+)?\\s+${VALUE_NAMES[$idx]}${valueRegex}(\\s|\$)" < "/etc/pam.d/common-password" ; then
echo "password requisite pam_cracklib.so ${VALUE_NAMES[$idx]}${defaultValue}" >> "/etc/pam.d/common-password"
fi
else
echo "/etc/pam.d/common-password doesn't exist" >&2
fi
done
for idx in "${!ARGS[@]}"
do
if ! grep -q -P "^\s*password\s+requisite\s+pam_cracklib.so.*\s+${ARGS[$idx]}\s*$" /etc/pam.d/common-password ; then
sed --follow-symlinks -i -E -e "s/^\\s*password\\s+requisite\\s+pam_cracklib.so.*\$/& ${NEW_ARGS[$idx]}/" /etc/pam.d/common-password
fi
done
|
Set Password Hashing Algorithm
[ref]groupThe system's default algorithm for storing password hashes in
/etc/shadow is SHA-512. This can be configured in several
locations. |
contains 4 rules |
Set PAM's Common Authentication Hashing Algorithm
[ref]ruleThe PAM system service can be configured to only store encrypted
representations of passwords. In
/etc/pam.d/common-auth ,
the
auth section of the file controls which PAM modules execute
during a password change. Set the pam_unix.so module in the
auth section to include the argument sha512 , as shown
below:
auth required pam_unix.so sha512 other arguments...
This will help ensure when local users change their authentication method,
hashes for the new authentications will be generated using the SHA-512
algorithm. This is the default.Rationale:Unapproved mechanisms used for authentication to the cryptographic module
are not verified and therefore cannot be relied on to provide
confidentiality or integrity, and data may be compromised.
This setting ensures user and group account administration utilities are
configured to store only encrypted representations of passwords.
Additionally, the crypt_style configuration option ensures the use
of a strong hashing algorithm that makes password cracking attacks more
difficult. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85754-0
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Set control_flag fact
set_fact:
control_flag: required
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85754-0
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Check to see if 'pam_unix.so' module is configured in '/etc/pam.d/common-auth'
shell: |
set -o pipefail
grep -E '^\s*auth\s+\S+\s+pam_unix.so' /etc/pam.d/common-auth || true
register: check_pam_module_result
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85754-0
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Configure 'pam_unix.so' module in '/etc/pam.d/common-auth'
lineinfile:
path: /etc/pam.d/common-auth
line: auth required pam_unix.so
state: present
when:
- '"pam" in ansible_facts.packages'
- '"pam_unix.so" not in check_pam_module_result.stdout'
tags:
- CCE-85754-0
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Ensure 'pam_unix.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+)\S+(\s+pam_unix.so\s+.*)
line: \g<1>required\g<2>
backrefs: true
when:
- '"pam" in ansible_facts.packages'
- control_flag|length
tags:
- CCE-85754-0
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Set argument_value fact
set_fact:
argument_value: ''
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85754-0
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Ensure "pam_unix.so" module has argument "sha512"
lineinfile:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+required\s+pam_unix.so(?:\s+\S+)*\s+sha512=)(?!)\S*((\s+\S+)*\s*\\*\s*)$
line: \g<1>\g<2>
backrefs: true
when:
- '"pam" in ansible_facts.packages'
- argument_value|length
tags:
- CCE-85754-0
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Check the presence of "sha512" argument in "pam_unix.so" module
shell: |
set -o pipefail
grep -E '^\s*auth\s+required\s+pam_unix.so.*\s+sha512(=|\s|\s*$)' /etc/pam.d/common-auth || true
register: check_pam_module_argument_result
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85754-0
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Add "sha512" argument to "pam_unix.so" module
lineinfile:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+required\s+pam_unix.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> sha512\g<2>
backrefs: true
when:
- '"pam" in ansible_facts.packages'
- '"sha512" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85754-0
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
if [ -e "/etc/pam.d/common-auth" ] ; then
valueRegex="" defaultValue=""
# non-empty values need to be preceded by an equals sign
[ -n "${valueRegex}" ] && valueRegex="=${valueRegex}"
# add an equals sign to non-empty values
[ -n "${defaultValue}" ] && defaultValue="=${defaultValue}"
# fix 'type' if it's wrong
if grep -q -P "^\\s*(?"'!'"auth\\s)[[:alnum:]]+\\s+[[:alnum:]]+\\s+pam_unix.so" < "/etc/pam.d/common-auth" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*)[[:alnum:]]+(\\s+[[:alnum:]]+\\s+pam_unix.so)/\\1auth\\2/" "/etc/pam.d/common-auth"
fi
# fix 'control' if it's wrong
if grep -q -P "^\\s*auth\\s+(?"'!'"required)[[:alnum:]]+\\s+pam_unix.so" < "/etc/pam.d/common-auth" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*auth\\s+)[[:alnum:]]+(\\s+pam_unix.so)/\\1required\\2/" "/etc/pam.d/common-auth"
fi
# fix the value for 'option' if one exists but does not match 'valueRegex'
if grep -q -P "^\\s*auth\\s+required\\s+pam_unix.so(\\s.+)?\\s+sha512(?"'!'"${valueRegex}(\\s|\$))" < "/etc/pam.d/common-auth" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*auth\\s+required\\s+pam_unix.so(\\s.+)?\\s)sha512=[^[:space:]]*/\\1sha512${defaultValue}/" "/etc/pam.d/common-auth"
# add 'option=default' if option is not set
elif grep -q -E "^\\s*auth\\s+required\\s+pam_unix.so" < "/etc/pam.d/common-auth" &&
grep -E "^\\s*auth\\s+required\\s+pam_unix.so" < "/etc/pam.d/common-auth" | grep -q -E -v "\\ssha512(=|\\s|\$)" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*auth\\s+required\\s+pam_unix.so[^\\n]*)/\\1 sha512${defaultValue}/" "/etc/pam.d/common-auth"
# add a new entry if none exists
elif ! grep -q -P "^\\s*auth\\s+required\\s+pam_unix.so(\\s.+)?\\s+sha512${valueRegex}(\\s|\$)" < "/etc/pam.d/common-auth" ; then
echo "auth required pam_unix.so sha512${defaultValue}" >> "/etc/pam.d/common-auth"
fi
else
echo "/etc/pam.d/common-auth doesn't exist" >&2
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Password Hashing Algorithm in /etc/libuser.conf
[ref]ruleIn /etc/libuser.conf , add or correct the following line in its
[defaults] section to ensure the system will use the SHA-512
algorithm for password hashing:
crypt_style = sha512 Rationale:Passwords need to be protected at all times, and encryption is the standard
method for protecting passwords. If passwords are not encrypted, they can
be plainly read (i.e., clear text) and easily compromised. Passwords that
are encrypted with a weak algorithm are no more protected than if they are
kepy in plain text.
This setting ensures user and group account administration utilities are
configured to store only encrypted representations of passwords.
Additionally, the crypt_style configuration option ensures the use
of a strong hashing algorithm that makes password cracking attacks more
difficult. Identifiers:
CCE-85798-7 References:
1, 12, 15, 16, 5, 5.6.2.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.13.11, CCI-000196, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(c), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1, 8.3.2, SRG-OS-000073-GPOS-00041 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85798-7
- CJIS-5.6.2.2
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_libuserconf
- name: Set Password Hashing Algorithm in /etc/libuser.conf
lineinfile:
dest: /etc/libuser.conf
insertafter: ^\s*\[defaults]
regexp: ^#?crypt_style
line: crypt_style = sha512
state: present
create: true
when: '"libuser" in ansible_facts.packages'
tags:
- CCE-85798-7
- CJIS-5.6.2.2
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_libuserconf
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q libuser; then
LIBUSER_CONF="/etc/libuser.conf"
CRYPT_STYLE_REGEX='[[:space:]]*\[defaults](.*(\n)+)+?[[:space:]]*crypt_style[[:space:]]*'
# Try find crypt_style in [defaults] section. If it is here, then change algorithm to sha512.
# If it isn't here, then add it to [defaults] section.
if grep -qzosP $CRYPT_STYLE_REGEX $LIBUSER_CONF ; then
sed -i "s/\(crypt_style[[:space:]]*=[[:space:]]*\).*/\1sha512/g" $LIBUSER_CONF
elif grep -qs "\[defaults]" $LIBUSER_CONF ; then
sed -i "/[[:space:]]*\[defaults]/a crypt_style = sha512" $LIBUSER_CONF
else
echo -e "[defaults]\ncrypt_style = sha512" >> $LIBUSER_CONF
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Password Hashing Algorithm in /etc/login.defs
[ref]ruleIn /etc/login.defs , add or correct the following line to ensure
the system will use SHA512 as the hashing algorithm:
ENCRYPT_METHOD SHA512 Rationale:Passwords need to be protected at all times, and encryption is the standard method for protecting passwords.
If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Passwords
that are encrypted with a weak algorithm are no more protected than if they are kept in plain text.
Using a stronger hashing algorithm makes password cracking attacks more difficult. Identifiers:
CCE-83279-0 References:
BP28(R32), 1, 12, 15, 16, 5, 5.6.2.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.13.11, CCI-000196, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(c), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1, 8.3.2, SRG-OS-000073-GPOS-00041, SLES-15-010260, 5.4.1.1, SV-234825r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83279-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-010260
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_logindefs
- name: XCCDF Value var_password_hashing_algorithm # promote to variable
set_fact:
var_password_hashing_algorithm: !!str SHA512
tags:
- always
- name: Set Password Hashing Algorithm in /etc/login.defs
lineinfile:
dest: /etc/login.defs
regexp: ^#?ENCRYPT_METHOD
line: ENCRYPT_METHOD {{ var_password_hashing_algorithm }}
state: present
create: true
when: '"shadow" in ansible_facts.packages'
tags:
- CCE-83279-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-010260
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_logindefs
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow; then
var_password_hashing_algorithm='SHA512'
if grep --silent ^ENCRYPT_METHOD /etc/login.defs ; then
sed -i "s/^ENCRYPT_METHOD .*/ENCRYPT_METHOD $var_password_hashing_algorithm/g" /etc/login.defs
else
echo "" >> /etc/login.defs
echo "ENCRYPT_METHOD $var_password_hashing_algorithm" >> /etc/login.defs
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set PAM''s Password Hashing Algorithm
[ref]ruleThe PAM system service can be configured to only store encrypted
representations of passwords. In "/etc/pam.d/common-password", the
password section of the file controls which PAM modules execute
during a password change. Set the pam_unix.so module in the
password section to include the argument sha512 , as shown
below:
password required pam_unix.so sha512 other arguments...
This will help ensure when local users change their passwords, hashes for
the new passwords will be generated using the SHA-512 algorithm. This is
the default.Rationale:Passwords need to be protected at all times, and encryption is the standard
method for protecting passwords. If passwords are not encrypted, they can
be plainly read (i.e., clear text) and easily compromised. Passwords that
are encrypted with a weak algorithm are no more protected than if they are
kepy in plain text.
This setting ensures user and group account administration utilities are
configured to store only encrypted representations of passwords.
Additionally, the crypt_style configuration option ensures the use
of a strong hashing algorithm that makes password cracking attacks more
difficult. Identifiers:
CCE-85565-0 References:
BP28(R32), 1, 12, 15, 16, 5, 5.6.2.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.13.11, CCI-000196, CCI-000803, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(c), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1, 8.3.2, SRG-OS-000073-GPOS-00041, SRG-OS-000120-GPOS-00061, SLES-15-020170, SV-234886r877397_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85565-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-020170
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- set_password_hashing_algorithm_systemauth
- name: Set PAM's Password Hashing Algorithm - Check if /etc/pam.d/common-password
file is present
ansible.builtin.stat:
path: /etc/pam.d/common-password
register: result_pam_file_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85565-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-020170
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- set_password_hashing_algorithm_systemauth
- name: Set PAM's Password Hashing Algorithm - Check the proper remediation for the
system
block:
- name: Set PAM's Password Hashing Algorithm - Define the PAM file to be edited
as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/common-password
- name: Set PAM's Password Hashing Algorithm - Check if system relies on authselect
tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Set PAM's Password Hashing Algorithm - Ensure authselect custom profile
is used if authselect is present
block:
- name: Set PAM's Password Hashing Algorithm - Check integrity of authselect current
profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Set PAM's Password Hashing Algorithm - Informative message based on the
authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because an authselect profile was
not selected or the selected profile is not intact.
- It is not recommended to manually edit the PAM files when authselect tool
is available.
- In cases where the default authselect profile does not cover a specific
demand, a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Set PAM's Password Hashing Algorithm - Get authselect current profile
ansible.builtin.shell:
cmd: authselect current -r | awk '{ print $1 }'
register: result_authselect_profile
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Set PAM's Password Hashing Algorithm - Define the current authselect profile
as a local fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is match("custom/")
- name: Set PAM's Password Hashing Algorithm - Define the new authselect custom
profile as a local fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: custom/hardening
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is not match("custom/")
- name: Set PAM's Password Hashing Algorithm - Get authselect current features
to also enable them in the custom profile
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- name: Set PAM's Password Hashing Algorithm - Check if any custom profile with
the same name was already created
ansible.builtin.stat:
path: /etc/authselect/{{ authselect_custom_profile }}
register: result_authselect_custom_profile_present
changed_when: false
when:
- authselect_current_profile is not match("custom/")
- name: Set PAM's Password Hashing Algorithm - Create an authselect custom profile
based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Set PAM's Password Hashing Algorithm - Ensure the authselect custom profile
is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
register: result_pam_authselect_select_profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Set PAM's Password Hashing Algorithm - Restore the authselect features
in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Set PAM's Password Hashing Algorithm - Change the PAM file to be edited
according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Set PAM's Password Hashing Algorithm - Check if expected PAM module line
is present in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+{{ 'required' | regex_escape() }}\s+pam_unix.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
- name: Set PAM's Password Hashing Algorithm - Include or update the PAM module
line in {{ pam_file_path }}
block:
- name: Set PAM's Password Hashing Algorithm - Check if required PAM module line
is present in {{ pam_file_path }} with different control
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+.*\s+pam_unix.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Set PAM's Password Hashing Algorithm - Ensure the correct control for
the required PAM module line in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: ^(\s*password\s+).*(\bpam_unix.so.*)
replace: \1required \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Set PAM's Password Hashing Algorithm - Ensure the required PAM module
line is included in {{ pam_file_path }}
ansible.builtin.lineinfile:
dest: '{{ pam_file_path }}'
line: password required pam_unix.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
- name: Set PAM's Password Hashing Algorithm - Check if the required PAM module
option is present in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*password\s+{{ 'required' | regex_escape() }}\s+pam_unix.so\s*.*\ssha512\b
state: absent
check_mode: true
changed_when: false
register: result_pam_module_sha512_option_present
- name: Set PAM's Password Hashing Algorithm - Ensure the "sha512" PAM option for
"pam_unix.so" is included in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
backrefs: true
regexp: ^(\s*password\s+{{ 'required' | regex_escape() }}\s+pam_unix.so.*)
line: \1 sha512
state: present
register: result_pam_sha512_add
when:
- result_pam_module_sha512_option_present.found == 0
- name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present.stat.exists
- |-
(result_pam_sha512_add is defined and result_pam_sha512_add.changed)
or (result_pam_sha512_edit is defined and result_pam_sha512_edit.changed)
when:
- '"pam" in ansible_facts.packages'
- result_pam_file_present.stat.exists
tags:
- CCE-85565-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-020170
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- PCI-DSSv4-8.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- set_password_hashing_algorithm_systemauth
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
if [ -e "/etc/pam.d/common-password" ] ; then
PAM_FILE_PATH="/etc/pam.d/common-password"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/common-password")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if ! grep -qP '^\s*password\s+'"required"'\s+pam_unix.so\s*.*' "$PAM_FILE_PATH"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*password\s+.*\s+pam_unix.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_unix.so.*)/\1'"required"' \2/' "$PAM_FILE_PATH"
else
echo 'password '"required"' pam_unix.so' >> "$PAM_FILE_PATH"
fi
fi
# Check the option
if ! grep -qP '^\s*password\s+'"required"'\s+pam_unix.so\s*.*\ssha512\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks '/\s*password\s+'"required"'\s+pam_unix.so.*/ s/$/ sha512/' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/common-password was not found" >&2
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure PAM Displays Last Logon/Access Notification
[ref]ruleTo configure the system to notify users of last logon/access using pam_lastlog ,
add or correct the pam_lastlog settings in /etc/pam.d/login
to include showfailed option, such as:
session optional pam_lastlog.so showfailed
And make sure that the silent option is not set for this specific line.Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report. Warning:
authselect contains an authselect feature to easily and properly enable Last Logon
notifications with pam_lastlog.so module. If a custom profile was created and used
in the system before this authselect feature was available, the new feature can't be used
with this custom profile and the remediation will fail. In this case, the custom profile
should be recreated or manually updated. Rationale:Users need to be aware of activity that occurs regarding their account. Providing users with
information regarding the number of unsuccessful attempts that were made to login to their
account allows the user to determine if any unauthorized activity has occurred and gives them
an opportunity to notify administrators. Identifiers:
CCE-85560-1 References:
1, 12, 15, 16, 5.5.2, DSS05.04, DSS05.10, DSS06.10, CCI-000052, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0582, 0584, 05885, 0586, 0846, 0957, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-9, AC-9(1), PR.AC-7, Req-10.2.4, 10.2.1.4, SRG-OS-000480-GPOS-00227, SLES-15-020080, SV-234873r858542_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85560-1
- CJIS-5.5.2
- DISA-STIG-SLES-15-020080
- NIST-800-53-AC-9
- NIST-800-53-AC-9(1)
- PCI-DSS-Req-10.2.4
- PCI-DSSv4-10.2.1.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Ensure PAM Displays Last Logon/Access Notification - Check if system relies
on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85560-1
- CJIS-5.5.2
- DISA-STIG-SLES-15-020080
- NIST-800-53-AC-9
- NIST-800-53-AC-9(1)
- PCI-DSS-Req-10.2.4
- PCI-DSSv4-10.2.1.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Ensure PAM Displays Last Logon/Access Notification - Collect the Available
authselect Features
ansible.builtin.command:
cmd: authselect list-features minimal
register: result_authselect_available_features
changed_when: false
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
tags:
- CCE-85560-1
- CJIS-5.5.2
- DISA-STIG-SLES-15-020080
- NIST-800-53-AC-9
- NIST-800-53-AC-9(1)
- PCI-DSS-Req-10.2.4
- PCI-DSSv4-10.2.1.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Ensure PAM Displays Last Logon/Access Notification - Configure pam_lastlog.so
Using authselect Feature
block:
- name: Ensure PAM Displays Last Logon/Access Notification - Check integrity of
authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Ensure PAM Displays Last Logon/Access Notification - Informative message
based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because an authselect profile was not
selected or the selected profile is not intact.
- It is not recommended to manually edit the PAM files when authselect tool
is available.
- In cases where the default authselect profile does not cover a specific demand,
a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Ensure PAM Displays Last Logon/Access Notification - Get authselect Features
Currently Enabled
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Ensure PAM Displays Last Logon/Access Notification - Ensure "with-silent-lastlog"
Feature is Disabled Using authselect Tool
ansible.builtin.command:
cmd: authselect disable-feature with-silent-lastlog
register: result_authselect_disable_feature_cmd
when:
- result_authselect_check_cmd is success
- result_authselect_features.stdout is search("with-silent-lastlog")
- name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect changes
are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_disable_feature_cmd is not skipped
- result_authselect_disable_feature_cmd is success
when:
- '"pam" in ansible_facts.packages'
- result_authselect_present.stat.exists
- result_authselect_available_features.stdout is search("with-silent-lastlog")
tags:
- CCE-85560-1
- CJIS-5.5.2
- DISA-STIG-SLES-15-020080
- NIST-800-53-AC-9
- NIST-800-53-AC-9(1)
- PCI-DSS-Req-10.2.4
- PCI-DSSv4-10.2.1.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Ensure PAM Displays Last Logon/Access Notification - Configure pam_lastlog.so
in appropriate PAM files
block:
- name: Ensure PAM Displays Last Logon/Access Notification - Define the PAM file
to be edited as a local fact
ansible.builtin.set_fact:
pam_file_path: /etc/pam.d/login
- name: Ensure PAM Displays Last Logon/Access Notification - Check if system relies
on authselect tool
ansible.builtin.stat:
path: /usr/bin/authselect
register: result_authselect_present
- name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect custom
profile is used if authselect is present
block:
- name: Ensure PAM Displays Last Logon/Access Notification - Check integrity of
authselect current profile
ansible.builtin.command:
cmd: authselect check
register: result_authselect_check_cmd
changed_when: false
failed_when: false
- name: Ensure PAM Displays Last Logon/Access Notification - Informative message
based on the authselect integrity check result
ansible.builtin.assert:
that:
- result_authselect_check_cmd.rc == 0
fail_msg:
- authselect integrity check failed. Remediation aborted!
- This remediation could not be applied because an authselect profile was
not selected or the selected profile is not intact.
- It is not recommended to manually edit the PAM files when authselect tool
is available.
- In cases where the default authselect profile does not cover a specific
demand, a custom authselect profile is recommended.
success_msg:
- authselect integrity check passed
- name: Ensure PAM Displays Last Logon/Access Notification - Get authselect current
profile
ansible.builtin.shell:
cmd: authselect current -r | awk '{ print $1 }'
register: result_authselect_profile
changed_when: false
when:
- result_authselect_check_cmd is success
- name: Ensure PAM Displays Last Logon/Access Notification - Define the current
authselect profile as a local fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is match("custom/")
- name: Ensure PAM Displays Last Logon/Access Notification - Define the new authselect
custom profile as a local fact
ansible.builtin.set_fact:
authselect_current_profile: '{{ result_authselect_profile.stdout }}'
authselect_custom_profile: custom/hardening
when:
- result_authselect_profile is not skipped
- result_authselect_profile.stdout is not match("custom/")
- name: Ensure PAM Displays Last Logon/Access Notification - Get authselect current
features to also enable them in the custom profile
ansible.builtin.shell:
cmd: authselect current | tail -n+3 | awk '{ print $2 }'
register: result_authselect_features
changed_when: false
when:
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- name: Ensure PAM Displays Last Logon/Access Notification - Check if any custom
profile with the same name was already created
ansible.builtin.stat:
path: /etc/authselect/{{ authselect_custom_profile }}
register: result_authselect_custom_profile_present
changed_when: false
when:
- authselect_current_profile is not match("custom/")
- name: Ensure PAM Displays Last Logon/Access Notification - Create an authselect
custom profile based on the current profile
ansible.builtin.command:
cmd: authselect create-profile hardening -b {{ authselect_current_profile
}}
when:
- result_authselect_check_cmd is success
- authselect_current_profile is not match("custom/")
- not result_authselect_custom_profile_present.stat.exists
- name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Ensure PAM Displays Last Logon/Access Notification - Ensure the authselect
custom profile is selected
ansible.builtin.command:
cmd: authselect select {{ authselect_custom_profile }}
register: result_pam_authselect_select_profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- authselect_current_profile is not match("custom/")
- authselect_custom_profile is not match(authselect_current_profile)
- name: Ensure PAM Displays Last Logon/Access Notification - Restore the authselect
features in the custom profile
ansible.builtin.command:
cmd: authselect enable-feature {{ item }}
loop: '{{ result_authselect_features.stdout_lines }}'
register: result_pam_authselect_restore_features
when:
- result_authselect_profile is not skipped
- result_authselect_features is not skipped
- result_pam_authselect_select_profile is not skipped
- name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
when:
- result_authselect_check_cmd is success
- result_authselect_profile is not skipped
- result_pam_authselect_restore_features is not skipped
- name: Ensure PAM Displays Last Logon/Access Notification - Change the PAM file
to be edited according to the custom authselect profile
ansible.builtin.set_fact:
pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
| basename }}
when:
- result_authselect_present.stat.exists
- name: Ensure PAM Displays Last Logon/Access Notification - Check if expected PAM
module line is present in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*session\s+{{ 'optional' | regex_escape() }}\s+pam_lastlog.so\s*.*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_present
- name: Ensure PAM Displays Last Logon/Access Notification - Include or update the
PAM module line in {{ pam_file_path }}
block:
- name: Ensure PAM Displays Last Logon/Access Notification - Check if required
PAM module line is present in {{ pam_file_path }} with different control
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*session\s+.*\s+pam_lastlog.so\s*
state: absent
check_mode: true
changed_when: false
register: result_pam_line_other_control_present
- name: Ensure PAM Displays Last Logon/Access Notification - Ensure the correct
control for the required PAM module line in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: ^(\s*session\s+).*(\bpam_lastlog.so.*)
replace: \1optional \2
register: result_pam_module_edit
when:
- result_pam_line_other_control_present.found == 1
- name: Ensure PAM Displays Last Logon/Access Notification - Ensure the required
PAM module line is included in {{ pam_file_path }}
ansible.builtin.lineinfile:
dest: '{{ pam_file_path }}'
insertafter: ^\s*session.*include\s+common-session$
line: session optional pam_lastlog.so
register: result_pam_module_add
when:
- result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
> 1
- name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect
changes are applied
ansible.builtin.command:
cmd: authselect apply-changes -b
when:
- result_authselect_present is defined
- result_authselect_present.stat.exists
- |-
(result_pam_module_add is defined and result_pam_module_add.changed)
or (result_pam_module_edit is defined and result_pam_module_edit.changed)
when:
- result_pam_line_present.found is defined
- result_pam_line_present.found == 0
- name: Ensure PAM Displays Last Logon/Access Notification - Check if the required
PAM module option is present in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
regexp: ^\s*session\s+{{ 'optional' | regex_escape() }}\s+pam_lastlog.so\s*.*\sshowfailed\b
state: absent
check_mode: true
changed_when: false
register: result_pam_module_showfailed_option_present
- name: Ensure PAM Displays Last Logon/Access Notification - Ensure the "showfailed"
PAM option for "pam_lastlog.so" is included in {{ pam_file_path }}
ansible.builtin.lineinfile:
path: '{{ pam_file_path }}'
backrefs: true
regexp: ^(\s*session\s+{{ 'optional' | regex_escape() }}\s+pam_lastlog.so.*)
line: \1 showfailed
state: present
register: result_pam_showfailed_add
when:
- result_pam_module_showfailed_option_present.found == 0
- name: Ensure PAM Displays Last Logon/Access Notification - Ensure the "silent"
option from "pam_lastlog.so" is not present in {{ pam_file_path }}
ansible.builtin.replace:
dest: '{{ pam_file_path }}'
regexp: (.*session.*{{ 'optional' | regex_escape() }}.*pam_lastlog.so.*)\bsilent\b=?[0-9a-zA-Z]*(.*)
replace: \1\2
register: result_pam_option_removal
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85560-1
- CJIS-5.5.2
- DISA-STIG-SLES-15-020080
- NIST-800-53-AC-9
- NIST-800-53-AC-9(1)
- PCI-DSS-Req-10.2.4
- PCI-DSSv4-10.2.1.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
if [ -f /usr/bin/authselect ]; then
if authselect list-features minimal | grep -q with-silent-lastlog; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
authselect disable-feature with-silent-lastlog
authselect apply-changes -b
else
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/login")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
if [ -e "$PAM_FILE_PATH" ] ; then
PAM_FILE_PATH="$PAM_FILE_PATH"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "$PAM_FILE_PATH")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if ! grep -qP '^\s*session\s+'"optional"'\s+pam_lastlog.so\s*.*' "$PAM_FILE_PATH"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*session\s+.*\s+pam_lastlog.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*session\s+).*(\bpam_lastlog.so.*)/\1'"optional"' \2/' "$PAM_FILE_PATH"
else
LAST_MATCH_LINE=$(grep -nP "^\s*session.*include\s+common-session$" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
if [ ! -z $LAST_MATCH_LINE ]; then
sed -i --follow-symlinks $LAST_MATCH_LINE' a session '"optional"' pam_lastlog.so' "$PAM_FILE_PATH"
else
echo 'session '"optional"' pam_lastlog.so' >> "$PAM_FILE_PATH"
fi
fi
fi
# Check the option
if ! grep -qP '^\s*session\s+'"optional"'\s+pam_lastlog.so\s*.*\sshowfailed\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks '/\s*session\s+'"optional"'\s+pam_lastlog.so.*/ s/$/ showfailed/' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "$PAM_FILE_PATH was not found" >&2
fi
if [ -e "$PAM_FILE_PATH" ] ; then
PAM_FILE_PATH="$PAM_FILE_PATH"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "$PAM_FILE_PATH")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*session\s+'"optional"'\s+pam_lastlog.so\s.*\bsilent\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*session.*'"optional"'.*pam_lastlog.so.*)\ssilent=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "$PAM_FILE_PATH was not found" >&2
fi
fi
else
if [ -e "/etc/pam.d/login" ] ; then
PAM_FILE_PATH="/etc/pam.d/login"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/login")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if ! grep -qP '^\s*session\s+'"optional"'\s+pam_lastlog.so\s*.*' "$PAM_FILE_PATH"; then
# Line matching group + control + module was not found. Check group + module.
if [ "$(grep -cP '^\s*session\s+.*\s+pam_lastlog.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
# The control is updated only if one single line matches.
sed -i -E --follow-symlinks 's/^(\s*session\s+).*(\bpam_lastlog.so.*)/\1'"optional"' \2/' "$PAM_FILE_PATH"
else
LAST_MATCH_LINE=$(grep -nP "^\s*session.*include\s+common-session$" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
if [ ! -z $LAST_MATCH_LINE ]; then
sed -i --follow-symlinks $LAST_MATCH_LINE' a session '"optional"' pam_lastlog.so' "$PAM_FILE_PATH"
else
echo 'session '"optional"' pam_lastlog.so' >> "$PAM_FILE_PATH"
fi
fi
fi
# Check the option
if ! grep -qP '^\s*session\s+'"optional"'\s+pam_lastlog.so\s*.*\sshowfailed\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks '/\s*session\s+'"optional"'\s+pam_lastlog.so.*/ s/$/ showfailed/' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/login was not found" >&2
fi
if [ -e "/etc/pam.d/login" ] ; then
PAM_FILE_PATH="/etc/pam.d/login"
if [ -f /usr/bin/authselect ]; then
if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
# If not already in use, a custom profile is created preserving the enabled features.
if [[ ! $CURRENT_PROFILE == custom/* ]]; then
ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
authselect create-profile hardening -b $CURRENT_PROFILE
CURRENT_PROFILE="custom/hardening"
authselect apply-changes -b --backup=before-hardening-custom-profile
authselect select $CURRENT_PROFILE
for feature in $ENABLED_FEATURES; do
authselect enable-feature $feature;
done
authselect apply-changes -b --backup=after-hardening-custom-profile
fi
PAM_FILE_NAME=$(basename "/etc/pam.d/login")
PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"
authselect apply-changes -b
fi
if grep -qP '^\s*session\s+'"optional"'\s+pam_lastlog.so\s.*\bsilent\b' "$PAM_FILE_PATH"; then
sed -i -E --follow-symlinks 's/(.*session.*'"optional"'.*pam_lastlog.so.*)\ssilent=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
fi
if [ -f /usr/bin/authselect ]; then
authselect apply-changes -b
fi
else
echo "/etc/pam.d/login was not found" >&2
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Protect Accounts by Restricting Password-Based Login
[ref]groupConventionally, Unix shell accounts are accessed by
providing a username and password to a login program, which tests
these values for correctness using the /etc/passwd and
/etc/shadow files. Password-based login is vulnerable to
guessing of weak passwords, and to sniffing and man-in-the-middle
attacks against passwords entered over a network or at an insecure
console. Therefore, mechanisms for accessing accounts by entering
usernames and passwords should be restricted to those which are
operationally necessary. |
contains 23 rules |
Set Account Expiration Parameters
[ref]groupAccounts can be configured to be automatically disabled
after a certain time period,
meaning that they will require administrator interaction to become usable again.
Expiration of accounts after inactivity can be set for all accounts by default
and also on a per-account basis, such as for accounts that are known to be temporary.
To configure automatic expiration of an account following
the expiration of its password (that is, after the password has expired and not been changed),
run the following command, substituting NUM_DAYS and USER appropriately:
$ sudo chage -I NUM_DAYS USER
Accounts, such as temporary accounts, can also be configured to expire on an explicitly-set date with the
-E option.
The file /etc/default/useradd controls
default settings for all newly-created accounts created with the system's
normal command line utilities.Warning:
This will only apply to newly created accounts |
contains 3 rules |
Set Account Expiration Following Inactivity
[ref]ruleTo specify the number of days after a password expires (which
signifies inactivity) until an account is permanently disabled, add or correct
the following line in /etc/default/useradd :
INACTIVE=90
If a password is currently on the verge of expiration, then
90
day(s) remain(s) until the account is automatically
disabled. However, if the password will not expire for another 60 days, then 60
days plus 90 day(s) could
elapse until the account would be automatically disabled. See the
useradd man page for more information.Rationale:Inactive identifiers pose a risk to systems and applications because attackers may exploit an inactive identifier and potentially obtain undetected access to the system.
Disabling inactive accounts ensures that accounts which may not have been responsibly removed are not available to attackers who may have compromised their credentials.
Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained. Identifiers:
CCE-85558-5 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.6.2.1.1, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.6, CCI-000017, CCI-000795, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, IA-4(e), AC-2(3), CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, Req-8.1.4, 8.2.6, SRG-OS-000118-GPOS-00060, SLES-15-020050, 5.4.1.5, SV-234871r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85558-5
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020050
- NIST-800-171-3.5.6
- NIST-800-53-AC-2(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-4(e)
- PCI-DSS-Req-8.1.4
- PCI-DSSv4-8.2.6
- account_disable_post_pw_expiration
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_account_disable_post_pw_expiration # promote to variable
set_fact:
var_account_disable_post_pw_expiration: !!str 90
tags:
- always
- name: Set Account Expiration Following Inactivity
lineinfile:
create: true
dest: /etc/default/useradd
regexp: ^INACTIVE
line: INACTIVE={{ var_account_disable_post_pw_expiration }}
when: '"shadow" in ansible_facts.packages'
tags:
- CCE-85558-5
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020050
- NIST-800-171-3.5.6
- NIST-800-53-AC-2(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-4(e)
- PCI-DSS-Req-8.1.4
- PCI-DSSv4-8.2.6
- account_disable_post_pw_expiration
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow; then
var_account_disable_post_pw_expiration='90'
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^INACTIVE")
# shellcheck disable=SC2059
printf -v formatted_output "%s=%s" "$stripped_key" "$var_account_disable_post_pw_expiration"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^INACTIVE\\>" "/etc/default/useradd"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^INACTIVE\\>.*/$escaped_formatted_output/gi" "/etc/default/useradd"
else
if [[ -s "/etc/default/useradd" ]] && [[ -n "$(tail -c 1 -- "/etc/default/useradd" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/default/useradd"
fi
cce="CCE-85558-5"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "/etc/default/useradd" >> "/etc/default/useradd"
printf '%s\n' "$formatted_output" >> "/etc/default/useradd"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure All Accounts on the System Have Unique Names
[ref]ruleEnsure accounts on the system have unique names.
To ensure all accounts have unique names, run the following command:
$ sudo getent passwd | awk -F: '{ print $1}' | uniq -d
If a username is returned, change or delete the username.Rationale:Unique usernames allow for accountability on the system. |
Ensure shadow Group is Empty
[ref]ruleThe shadow group allows system programs which require access the ability
to read the /etc/shadow file. No users should be assigned to the shadow group. Warning:
This rule remediation will ensure the group membership is empty in /etc/group. To avoid any
disruption the remediation won't change the primary group of users in /etc/passwd if any
user has the shadow GID as primary group. Rationale:Any users assigned to the shadow group would be granted read access to the
/etc/shadow file. If attackers can gain read access to the /etc/shadow file,
they can easily run a password cracking program against the hashed passwords
to break them. Other security information that is stored in the /etc/shadow
file (such as expiration) could also be useful to subvert additional user
accounts. Remediation Shell script: (show)
sed -ri 's/(^shadow:[^:]*:[^:]*:)([^:]+$)/\1/' /etc/group
|
Set Password Expiration Parameters
[ref]groupThe file /etc/login.defs controls several
password-related settings. Programs such as passwd ,
su , and
login consult /etc/login.defs to determine
behavior with regard to password aging, expiration warnings,
and length. See the man page login.defs(5) for more information.
Users should be forced to change their passwords, in order to
decrease the utility of compromised passwords. However, the need to
change passwords often should be balanced against the risk that
users will reuse or write down passwords if forced to change them
too often. Forcing password changes every 90-360 days, depending on
the environment, is recommended. Set the appropriate value as
PASS_MAX_DAYS and apply it to existing accounts with the
-M flag.
The PASS_MIN_DAYS (-m ) setting prevents password
changes for 7 days after the first change, to discourage password
cycling. If you use this setting, train users to contact an administrator
for an emergency password change in case a new password becomes
compromised. The PASS_WARN_AGE (-W ) setting gives
users 7 days of warnings at login time that their passwords are about to expire.
For example, for each existing human user USER, expiration parameters
could be adjusted to a 180 day maximum password age, 7 day minimum password
age, and 7 day warning period with the following command:
$ sudo chage -M 180 -m 7 -W 7 USER |
contains 5 rules |
Set Password Maximum Age
[ref]ruleTo specify password maximum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line:
PASS_MAX_DAYS 90
A value of 180 days is sufficient for many environments.
The DoD requirement is 60.
The profile requirement is 90 .Rationale:Any password, no matter how complex, can eventually be cracked. Therefore, passwords
need to be changed periodically. If the operating system does not limit the lifetime
of passwords and force users to change their passwords, there is the risk that the
operating system passwords could be compromised.
Setting the password maximum age ensures users are required to
periodically change their passwords. Requiring shorter password lifetimes
increases the risk of users writing down the password in a convenient
location subject to physical compromise. Identifiers:
CCE-85570-0 References:
BP28(R18), 1, 12, 15, 16, 5, 5.6.2.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.6, CCI-000199, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(f), IA-5(1)(d), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.4, 8.3.9, SRG-OS-000076-GPOS-00044, SLES-15-020220, 5.4.1.2, SV-234891r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85570-0
- CJIS-5.6.2.1
- DISA-STIG-SLES-15-020220
- NIST-800-171-3.5.6
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.4
- PCI-DSSv4-8.3.9
- accounts_maximum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_maximum_age_login_defs # promote to variable
set_fact:
var_accounts_maximum_age_login_defs: !!str 90
tags:
- always
- name: Set Password Maximum Age
lineinfile:
create: true
dest: /etc/login.defs
regexp: ^#?PASS_MAX_DAYS
line: PASS_MAX_DAYS {{ var_accounts_maximum_age_login_defs }}
when: '"shadow" in ansible_facts.packages'
tags:
- CCE-85570-0
- CJIS-5.6.2.1
- DISA-STIG-SLES-15-020220
- NIST-800-171-3.5.6
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.4
- PCI-DSSv4-8.3.9
- accounts_maximum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow; then
var_accounts_maximum_age_login_defs='90'
grep -q ^PASS_MAX_DAYS /etc/login.defs && \
sed -i "s/PASS_MAX_DAYS.*/PASS_MAX_DAYS $var_accounts_maximum_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]; then
echo "PASS_MAX_DAYS $var_accounts_maximum_age_login_defs" >> /etc/login.defs
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set Existing Passwords Maximum Age
[ref]ruleConfigure non-compliant accounts to enforce a 90-day maximum password lifetime
restriction by running the following command:
$ sudo chage -M 90 USER Rationale:Any password, no matter how complex, can eventually be cracked. Therefore,
passwords need to be changed periodically. If the operating system does
not limit the lifetime of passwords and force users to change their
passwords, there is the risk that the operating system passwords could be
compromised. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_accounts_maximum_age_login_defs # promote to variable
set_fact:
var_accounts_maximum_age_login_defs: !!str 90
tags:
- always
- name: Collect users with not correct maximum time period between password changes
ansible.builtin.command:
cmd: awk -F':' '(/^[^:]+:[^!*]/ && ($5 > {{ var_accounts_maximum_age_login_defs
}} || $5 == "")) {print $1}' /etc/shadow
register: user_names
tags:
- CCE-85571-8
- DISA-STIG-SLES-15-020230
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- PCI-DSSv4-8.3.9
- accounts_password_set_max_life_existing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Change the maximum time period between password changes
ansible.builtin.command:
cmd: passwd -q -x {{ var_accounts_maximum_age_login_defs }} {{ item }}
with_items: '{{ user_names.stdout_lines }}'
when: user_names.stdout_lines | length > 0
tags:
- CCE-85571-8
- DISA-STIG-SLES-15-020230
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- PCI-DSSv4-8.3.9
- accounts_password_set_max_life_existing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
var_accounts_maximum_age_login_defs='90'
while IFS= read -r i; do
passwd -q -x $var_accounts_maximum_age_login_defs $i
done < <(awk -v var="$var_accounts_maximum_age_login_defs" -F: '(/^[^:]+:[^!*]/ && ($5 > var || $5 == "")) {print $1}' /etc/shadow)
|
Set Existing Passwords Warning Age
[ref]ruleTo configure how many days prior to password expiration that a warning will be issued to
users, run the command:
$ sudo chage --warndays 7 USER
The DoD requirement is 7, and CIS recommendation is no less than 7 days.
This profile requirement is 7 .Rationale:Providing an advance warning that a password will be expiring gives users
time to think of a secure password. Users caught unaware may choose a simple
password or write it down where it may be discovered. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: XCCDF Value var_accounts_password_warn_age_login_defs # promote to variable
set_fact:
var_accounts_password_warn_age_login_defs: !!str 7
tags:
- always
- name: Set Existing Passwords Warning Age - Collect Users With Incorrect Number of
Days of Warning Before Password Expires
ansible.builtin.command:
cmd: awk -F':' '(($6 < {{ var_accounts_password_warn_age_login_defs }} || $6 ==
"") && $2 ~ /^\$/) {print $1}' /etc/shadow
register: result_pass_warn_age_user_names
changed_when: false
tags:
- CCE-92479-5
- NIST-800-53-IA-5(1).1(v)
- PCI-DSSv4-8.3.9
- accounts_password_set_warn_age_existing
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set Existing Passwords Warning Age - Ensure the Number of Days of Warning
Before Password Expires
ansible.builtin.command:
cmd: chage --warndays {{ var_accounts_password_warn_age_login_defs }} {{ item
}}
with_items: '{{ result_pass_warn_age_user_names.stdout_lines }}'
when: result_pass_warn_age_user_names.stdout_lines | length > 0
tags:
- CCE-92479-5
- NIST-800-53-IA-5(1).1(v)
- PCI-DSSv4-8.3.9
- accounts_password_set_warn_age_existing
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
var_accounts_password_warn_age_login_defs='7'
while IFS= read -r i; do
chage --warndays $var_accounts_password_warn_age_login_defs $i
done < <(awk -v var="$var_accounts_password_warn_age_login_defs" -F: '(($6 < var || $6 == "") && $2 ~ /^\$/) {print $1}' /etc/shadow)
|
Set Password Warning Age
[ref]ruleTo specify how many days prior to password
expiration that a warning will be issued to users,
edit the file /etc/login.defs and add or correct
the following line:
PASS_WARN_AGE 7
The DoD requirement is 7.
The profile requirement is 7 .Rationale:Setting the password warning age enables users to
make the change at a practical time. Identifiers:
CCE-91335-0 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.8, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, 0418, 1055, 1402, A.12.4.1, A.12.4.3, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, IA-5(f), IA-5(1)(d), CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, Req-8.2.4, 8.3.9, 5.4.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-91335-0
- NIST-800-171-3.5.8
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.4
- PCI-DSSv4-8.3.9
- accounts_password_warn_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_password_warn_age_login_defs # promote to variable
set_fact:
var_accounts_password_warn_age_login_defs: !!str 7
tags:
- always
- name: Set Password Warning Age
lineinfile:
dest: /etc/login.defs
regexp: ^PASS_WARN_AGE *[0-9]*
state: present
line: PASS_WARN_AGE {{ var_accounts_password_warn_age_login_defs }}
create: true
when: '"shadow" in ansible_facts.packages'
tags:
- CCE-91335-0
- NIST-800-171-3.5.8
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.4
- PCI-DSSv4-8.3.9
- accounts_password_warn_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow; then
var_accounts_password_warn_age_login_defs='7'
grep -q ^PASS_WARN_AGE /etc/login.defs && \
sed -i "s/PASS_WARN_AGE.*/PASS_WARN_AGE\t$var_accounts_password_warn_age_login_defs/g" /etc/login.defs
if ! [ $? -eq 0 ]
then
echo -e "PASS_WARN_AGE\t$var_accounts_password_warn_age_login_defs" >> /etc/login.defs
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set existing passwords a period of inactivity before they been locked
[ref]ruleConfigure user accounts that have been inactive for over a given period of time
to be automatically disabled by running the following command:
$ sudo chage --inactive 30USER Rationale:Inactive accounts pose a threat to system security since the users are not logging in to
notice failed login attempts or other anomalies. Identifiers:
CCE-92480-3 References:
DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.6, CCI-000017, CCI-000795, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, IA-4(e), AC-2(3), CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, Req-8.1.4, 8.2.6, SRG-OS-000118-GPOS-00060, 5.4.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_account_disable_post_pw_expiration # promote to variable
set_fact:
var_account_disable_post_pw_expiration: !!str 90
tags:
- always
- name: Collect users with not correct INACTIVE parameter set
ansible.builtin.command:
cmd: awk -F':' '(($7 > {{ var_account_disable_post_pw_expiration }} || $7 == "")
&& $2 ~ /^\$/) {print $1}' /etc/shadow
register: user_names
changed_when: false
tags:
- CCE-92480-3
- NIST-800-171-3.5.6
- NIST-800-53-AC-2(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-4(e)
- PCI-DSS-Req-8.1.4
- PCI-DSSv4-8.2.6
- accounts_set_post_pw_existing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Change the period of inactivity
ansible.builtin.command:
cmd: chage --inactive {{ var_account_disable_post_pw_expiration }} {{ item }}
with_items: '{{ user_names.stdout_lines }}'
when: user_names.stdout_lines | length > 0
tags:
- CCE-92480-3
- NIST-800-171-3.5.6
- NIST-800-53-AC-2(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-4(e)
- PCI-DSS-Req-8.1.4
- PCI-DSSv4-8.2.6
- accounts_set_post_pw_existing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
var_account_disable_post_pw_expiration='90'
while IFS= read -r i; do
chage --inactive $var_account_disable_post_pw_expiration $i
done < <(awk -v var="$var_account_disable_post_pw_expiration" -F: '(($7 > var || $7 == "") && $2 ~ /^\$/) {print $1}' /etc/shadow)
|
Verify Proper Storage and Existence of Password
Hashes
[ref]groupBy default, password hashes for local accounts are stored
in the second field (colon-separated) in
/etc/shadow . This file should be readable only by
processes running with root credentials, preventing users from
casually accessing others' password hashes and attempting
to crack them.
However, it remains possible to misconfigure the system
and store password hashes
in world-readable files such as /etc/passwd , or
to even store passwords themselves in plaintext on the system.
Using system-provided tools for password change/creation
should allow administrators to avoid such misconfiguration. |
contains 5 rules |
Verify All Account Password Hashes are Shadowed
[ref]ruleIf any password hashes are stored in /etc/passwd (in the second field,
instead of an x or * ), the cause of this misconfiguration should be
investigated. The account should have its password reset and the hash should be
properly stored, or the account should be deleted entirely. Rationale:The hashes for all user account passwords should be stored in
the file /etc/shadow and never in /etc/passwd ,
which is readable by all users. Identifiers:
CCE-85846-4 References:
1, 12, 15, 16, 5, 5.5.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.10, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 1410, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(h), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1, 8.3.2, 6.2.1 |
Ensure all users last password change date is in the past
[ref]ruleAll users should have a password change date in the past. Warning:
Automatic remediation is not available, in order to avoid any system disruption. Rationale:If a user recorded password change date is in the future then they could
bypass any set password expiration. |
All GIDs referenced in /etc/passwd must be defined in /etc/group
[ref]ruleAdd a group to the system for each GID referenced without a corresponding group. Rationale:If a user is assigned the Group Identifier (GID) of a group not existing on the system, and a group
with the Group Identifier (GID) is subsequently created, the user may have unintended rights to
any files associated with the group. Identifiers:
CCE-85847-2 References:
1, 12, 15, 16, 5, 5.5.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000764, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-2, CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.5.a, 8.2.2, SRG-OS-000104-GPOS-00051, 6.2.13 |
Prevent Login to Accounts With Empty Password
[ref]ruleIf an account is configured for password authentication
but does not have an assigned password, it may be possible to log
into the account without authentication. Remove any instances of the
nullok in
password authentication configurations in /etc/pam.d/
to prevent logins with empty passwords. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
Note that this rule is not applicable for systems running within a
container. Having user with empty password within a container is not
considered a risk, because it should not be possible to directly login into
a container anyway. Rationale:If an account has an empty password, anyone could log in and
run commands with the privileges of that account. Accounts with
empty passwords should never be used in operational environments. Identifiers:
CCE-85576-7 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2, APO01.06, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.10, 3.1.1, 3.1.5, CCI-000366, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, IA-5(1)(a), IA-5(c), CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, FIA_UAU.1, Req-8.2.3, 8.3.1, SRG-OS-000480-GPOS-00227, SLES-15-020300, SV-234898r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Find files in /etc/pam.d/ with password auth
find:
paths: /etc/pam.d
contains: .*pam_unix\.so.*nullok.*
recurse: true
register: find_pam_conf_files_result
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85576-7
- CJIS-5.5.2
- DISA-STIG-SLES-15-020300
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.1
- configure_strategy
- high_severity
- low_complexity
- medium_disruption
- no_empty_passwords
- no_reboot_needed
- name: Prevent Log In to Accounts with Empty Password
replace:
dest: '{{ item.path }}'
regexp: nullok
with_items: '{{ find_pam_conf_files_result.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85576-7
- CJIS-5.5.2
- DISA-STIG-SLES-15-020300
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- PCI-DSSv4-8.3.1
- configure_strategy
- high_severity
- low_complexity
- medium_disruption
- no_empty_passwords
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
PAM_PATH="/etc/pam.d/"
NULLOK_FILES=$(grep -rl ".*pam_unix\\.so.*nullok.*" ${PAM_PATH})
for FILE in ${NULLOK_FILES}; do
sed --follow-symlinks -i 's/\<nullok\>//g' ${FILE}
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure There Are No Accounts With Blank or Null Passwords
[ref]ruleCheck the "/etc/shadow" file for blank passwords with the
following command:
$ sudo awk -F: '!$2 {print $1}' /etc/shadow
If the command returns any results, this is a finding.
Configure all accounts on the system to have a password or lock
the account with the following commands:
Perform a password reset:
$ sudo passwd [username]
Lock an account:
$ sudo passwd -l [username] Warning:
Note that this rule is not applicable for systems running within a container. Having user with empty password within a container is not considered a risk, because it should not be possible to directly login into a container anyway. Rationale:If an account has an empty password, anyone could log in and
run commands with the privileges of that account. Accounts with
empty passwords should never be used in operational environments. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Collect users with no password
command: |
awk -F: '!$2 {print $1}' /etc/shadow
register: users_nopasswd
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91155-2
- DISA-STIG-SLES-15-020181
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSSv4-2.2.2
- high_severity
- low_complexity
- low_disruption
- no_empty_passwords_etc_shadow
- no_reboot_needed
- restrict_strategy
- name: Lock users with no password
command: |
passwd -l {{ item }}
with_items: '{{ users_nopasswd.stdout_lines }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- users_nopasswd.stdout_lines | length > 0
tags:
- CCE-91155-2
- DISA-STIG-SLES-15-020181
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSSv4-2.2.2
- high_severity
- low_complexity
- low_disruption
- no_empty_passwords_etc_shadow
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
readarray -t users_with_empty_pass < <(sudo awk -F: '!$2 {print $1}' /etc/shadow)
for user_with_empty_pass in "${users_with_empty_pass[@]}"
do
passwd -l $user_with_empty_pass
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Restrict Root Logins
[ref]groupDirect root logins should be allowed only for emergency use.
In normal situations, the administrator should access the system
via a unique unprivileged account, and then use su or sudo to execute
privileged commands. Discouraging administrators from accessing the
root account directly ensures an audit trail in organizations with
multiple administrators. Locking down the channels through which
root can connect directly also reduces opportunities for
password-guessing against the root account. The login program
uses the file /etc/securetty to determine which interfaces
should allow root logins.
The virtual devices /dev/console
and /dev/tty* represent the system consoles (accessible via
the Ctrl-Alt-F1 through Ctrl-Alt-F6 keyboard sequences on a default
installation). The default securetty file also contains /dev/vc/* .
These are likely to be deprecated in most environments, but may be retained
for compatibility. Root should also be prohibited from connecting
via network protocols. Other sections of this document
include guidance describing how to prevent root from logging in via SSH. |
contains 7 rules |
Verify Only Root Has UID 0
[ref]ruleIf any account other than root has a UID of 0, this misconfiguration should
be investigated and the accounts other than root should be removed or have
their UID changed.
If the account is associated with system commands or applications the UID
should be changed to one greater than "0" but less than "1000."
Otherwise assign a UID greater than "1000" that has not already been
assigned. Rationale:An account has root authority if it has a UID of 0. Multiple accounts
with a UID of 0 afford more opportunity for potential intruders to
guess a password for a privileged account. Proper configuration of
sudo is recommended to afford multiple system administrators
access to root privileges in an accountable manner. Identifiers:
CCE-85664-1 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.10, 3.1.1, 3.1.5, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CM-6(b), CM-6.1(iv), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, Req-8.5, 8.2.1, SRG-OS-000480-GPOS-00227, SLES-15-020100, 6.2.3, SV-234876r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Get all /etc/passwd file entries
getent:
database: passwd
split: ':'
tags:
- CCE-85664-1
- DISA-STIG-SLES-15-020100
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSS-Req-8.5
- PCI-DSSv4-8.2.1
- accounts_no_uid_except_zero
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
- name: Lock the password of the user accounts other than root with uid 0
command: passwd -l {{ item.key }}
loop: '{{ getent_passwd | dict2items | rejectattr(''key'', ''search'', ''root'')
| list }}'
when: item.value.1 == '0'
tags:
- CCE-85664-1
- DISA-STIG-SLES-15-020100
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSS-Req-8.5
- PCI-DSSv4-8.2.1
- accounts_no_uid_except_zero
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
awk -F: '$3 == 0 && $1 != "root" { print $1 }' /etc/passwd | xargs --no-run-if-empty --max-lines=1 passwd -l
|
Verify Root Has A Primary GID 0
[ref]ruleThe root user should have a primary group of 0. Rationale:To help ensure that root-owned files are not inadvertently exposed to other users. |
Ensure the Group Used by pam_wheel.so Module Exists on System and is Empty
[ref]ruleEnsure that the group sugroup referenced by
var_pam_wheel_group_for_su variable and used as value for the pam_wheel.so
group option exists and has no members. This empty group used by
pam_wheel.so in /etc/pam.d/su ensures that no user can run commands with
altered privileges through the su command. Warning:
Note that this rule just ensures the group exists and has no members. This rule does not
configure pam_wheel.so module. The pam_wheel.so module configuration is
accomplished by use_pam_wheel_group_for_su rule. Rationale:The su program allows to run commands with a substitute user and group ID.
It is commonly used to run commands as the root user.
Limiting access to such command is considered a good security practice. Identifiers:
CCE-92528-9 References:
2.2.6, 5.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-92528-9
- PCI-DSSv4-2.2.6
- ensure_pam_wheel_group_empty
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_pam_wheel_group_for_su # promote to variable
set_fact:
var_pam_wheel_group_for_su: !!str sugroup
tags:
- always
- name: Ensure the Group Used by pam_wheel.so Module Exists on System and is Empty
- Ensure {{ var_pam_wheel_group_for_su }} Group Exists
ansible.builtin.group:
name: '{{ var_pam_wheel_group_for_su }}'
state: present
when: '"pam" in ansible_facts.packages'
tags:
- CCE-92528-9
- PCI-DSSv4-2.2.6
- ensure_pam_wheel_group_empty
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure the Group Used by pam_wheel.so Module Exists on System and is Empty
- Ensure {{ var_pam_wheel_group_for_su }} Group is Empty
ansible.builtin.lineinfile:
path: /etc/group
regexp: ^({{ var_pam_wheel_group_for_su }}:[^:]+:[0-9]+:).*$
line: \1
backrefs: true
when: '"pam" in ansible_facts.packages'
tags:
- CCE-92528-9
- PCI-DSSv4-2.2.6
- ensure_pam_wheel_group_empty
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_pam_wheel_group_for_su='sugroup'
if ! grep -q "^${var_pam_wheel_group_for_su}:[^:]*:[^:]*:[^:]*" /etc/group; then
groupadd ${var_pam_wheel_group_for_su}
fi
# group must be empty
gpasswd -M '' ${var_pam_wheel_group_for_su}
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Direct root Logins Not Allowed
[ref]ruleTo further limit access to the root account, administrators
can disable root logins at the console by editing the /etc/securetty file.
This file lists all devices the root user is allowed to login to. If the file does
not exist at all, the root user can login through any communication device on the
system, whether via the console or via a raw network interface. This is dangerous
as user can login to the system as root via Telnet, which sends the password in
plain text over the network. By default, SUSE Linux Enterprise 15's
/etc/securetty file only allows the root user to login at the console
physically attached to the system. To prevent root from logging in, remove the
contents of this file. To prevent direct root logins, remove the contents of this
file by typing the following command:
$ sudo echo > /etc/securetty
Warning:
This rule only checks the /etc/securetty file existence and its content.
If you need to restrict user access using the /etc/securetty file, make sure
the pam_securetty.so PAM module is properly enabled in relevant PAM files. Rationale:Disabling direct root logins ensures proper accountability and multifactor
authentication to privileged accounts. Users will first login, then escalate
to privileged (root) access via su / sudo. This is required for FISMA Low
and FISMA Moderate systems. Identifiers:
CCE-91427-5 References:
BP28(R19), 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.1, 3.1.6, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-2, CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, 8.6.1, 5.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Direct root Logins Not Allowed
copy:
dest: /etc/securetty
content: ''
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91427-5
- NIST-800-171-3.1.1
- NIST-800-171-3.1.6
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-2
- PCI-DSSv4-8.6.1
- low_complexity
- low_disruption
- medium_severity
- no_direct_root_logins
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
echo > /etc/securetty
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure that System Accounts Do Not Run a Shell Upon Login
[ref]ruleSome accounts are not associated with a human user of the system, and exist to perform some
administrative functions. Should an attacker be able to log into these accounts, they should
not be granted access to a shell.
The login shell for each local account is stored in the last field of each line in
/etc/passwd . System accounts are those user accounts with a user ID less than
1000 . The user ID is stored in the third field. If any system account
other than root has a login shell, disable it with the command:
$ sudo usermod -s /sbin/nologin account Warning:
Do not perform the steps in this section on the root account. Doing so might cause the
system to become inaccessible. Rationale:Ensuring shells are not given to system accounts upon login makes it more difficult for
attackers to make use of system accounts. Identifiers:
CCE-85672-4 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS06.03, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, 1491, A.12.4.1, A.12.4.3, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-6, CM-6(a), CM-6(b), CM-6.1(iv), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, 8.2.2, SRG-OS-000480-GPOS-00227, SLES-15-020091, 5.4.2, SV-234875r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Ensure that System Accounts Do Not Run a Shell Upon Login - Get All Local
Users From /etc/passwd
ansible.builtin.getent:
database: passwd
split: ':'
tags:
- CCE-85672-4
- DISA-STIG-SLES-15-020091
- NIST-800-53-AC-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSSv4-8.2.2
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- no_shelllogin_for_systemaccounts
- restrict_strategy
- name: Ensure that System Accounts Do Not Run a Shell Upon Login - Create local_users
Variable From getent_passwd Facts
ansible.builtin.set_fact:
local_users: '{{ ansible_facts.getent_passwd | dict2items }}'
tags:
- CCE-85672-4
- DISA-STIG-SLES-15-020091
- NIST-800-53-AC-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSSv4-8.2.2
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- no_shelllogin_for_systemaccounts
- restrict_strategy
- name: Ensure that System Accounts Do Not Run a Shell Upon Login - Disable Login
Shell for System Accounts
ansible.builtin.user:
name: '{{ item.key }}'
shell: /sbin/nologin
loop: '{{ local_users }}'
when:
- item.key not in ['root']
- item.value[1]|int < 1000
- item.value[5] not in ['/sbin/shutdown', '/sbin/halt', '/bin/sync']
tags:
- CCE-85672-4
- DISA-STIG-SLES-15-020091
- NIST-800-53-AC-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSSv4-8.2.2
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- no_shelllogin_for_systemaccounts
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
readarray -t systemaccounts < <(awk -F: '($3 < 1000 && $3 != root \
&& $7 != "\/sbin\/shutdown" && $7 != "\/sbin\/halt" && $7 != "\/bin\/sync") \
{ print $1 }' /etc/passwd)
for systemaccount in "${systemaccounts[@]}"; do
usermod -s /sbin/nologin "$systemaccount"
done
|
Restrict Virtual Console Root Logins
[ref]ruleTo restrict root logins through the (deprecated) virtual console devices,
ensure lines of this form do not appear in /etc/securetty :
vc/1
vc/2
vc/3
vc/4 Rationale:Preventing direct root login to virtual console devices
helps ensure accountability for actions taken on the system
using the root account. Identifiers:
CCE-91430-9 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.1, 3.1.5, CCI-000770, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6, CM-6(a), PR.AC-4, PR.DS-5, 8.6.1, SRG-OS-000324-GPOS-00125, 5.5 Remediation Shell script: (show)
sed -i '/^vc\//d' /etc/securetty
|
Enforce Usage of pam_wheel with Group Parameter for su Authentication
[ref]ruleTo ensure that only users who are members of the group set in the group option of
pam_wheel.so module can run commands with altered privileges through the su
command, make sure that the following line exists in the file /etc/pam.d/su :
auth required pam_wheel.so use_uid group=sugroup Warning:
Note that ensure_pam_wheel_group_empty rule complements this requirement by
ensuring the referenced group exists and has no members. Rationale:The su program allows to run commands with a substitute user and group ID.
It is commonly used to run commands as the root user.
Limiting access to such command is considered a good security practice. Identifiers:
CCE-92522-2 References:
2.2.6, 5.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-92522-2
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- use_pam_wheel_group_for_su
- name: XCCDF Value var_pam_wheel_group_for_su # promote to variable
set_fact:
var_pam_wheel_group_for_su: !!str sugroup
tags:
- always
- name: Enforce Usage of pam_wheel with Group Parameter for su Authentication - Add
the group to the /etc/pam.d/su file
ansible.builtin.lineinfile:
path: /etc/pam.d/su
state: present
regexp: ^[\s]*#[\s]*auth[\s]+required[\s]+pam_wheel\.so[\s]+use_uid group=$
line: auth required pam_wheel.so use_uid group={{ var_pam_wheel_group_for_su
}}
when: '"pam" in ansible_facts.packages'
tags:
- CCE-92522-2
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- use_pam_wheel_group_for_su
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
var_pam_wheel_group_for_su='sugroup'
PAM_CONF=/etc/pam.d/su
pamstr=$(grep -P '^auth\s+required\s+pam_wheel\.so\s+(?=[^#]*\buse_uid\b)(?=[^#]*\bgroup=)' ${PAM_CONF})
if [ -z "$pamstr" ]; then
sed -Ei '/^auth\b.*\brequired\b.*\bpam_wheel\.so/d' ${PAM_CONF} # remove any remaining uncommented pam_wheel.so line
sed -Ei "/^auth\s+sufficient\s+pam_rootok\.so.*$/a auth required pam_wheel.so use_uid group=${var_pam_wheel_group_for_su}" ${PAM_CONF}
else
group_val=$(echo -n "$pamstr" | grep -Eo '\bgroup=[_a-z][-0-9_a-z]*' | cut -d '=' -f 2)
if [ -z "${group_val}" ] || [ ${group_val} != ${var_pam_wheel_group_for_su} ]; then
sed -Ei "s/(^auth\s+required\s+pam_wheel.so\s+[^#]*group=)[_a-z][-0-9_a-z]*/\1${var_pam_wheel_group_for_su}/" ${PAM_CONF}
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure All Accounts on the System Have Unique User IDs
[ref]ruleChange user IDs (UIDs), or delete accounts, so each has a unique name. Warning:
Automatic remediation of this control is not available due to unique requirements of each
system. Rationale:To assure accountability and prevent unauthenticated access, interactive users must be identified and authenticated to prevent potential misuse and compromise of the system. Identifiers:
CCE-83277-4 References:
CCI-000135, CCI-000764, CCI-000804, Req-8.1.1, 8.2.1, SRG-OS-000104-GPOS-00051, SRG-OS-000121-GPOS-00062, SRG-OS-000042-GPOS-00020, SLES-15-010230, 6.2.14, SV-234822r622137_rule |
Ensure All Groups on the System Have Unique Group ID
[ref]ruleChange the group name or delete groups, so each has a unique id. Warning:
Automatic remediation of this control is not available due to the unique requirements of each system. Rationale:To assure accountability and prevent unauthenticated access, groups must be identified uniquely to prevent potential misuse and compromise of the system. |
Ensure All Groups on the System Have Unique Group Names
[ref]ruleChange the group name or delete groups, so each has a unique name. Warning:
Automatic remediation of this control is not available due to the unique requirements of each system. Rationale:To assure accountability and prevent unauthenticated access, groups must be identified uniquely to prevent potential misuse and compromise of the system. |
Secure Session Configuration Files for Login Accounts
[ref]groupWhen a user logs into a Unix account, the system
configures the user's session by reading a number of files. Many of
these files are located in the user's home directory, and may have
weak permissions as a result of user error or misconfiguration. If
an attacker can modify or even read certain types of account
configuration information, they can often gain full access to the
affected user's account. Therefore, it is important to test and
correct configuration file permissions for interactive accounts,
particularly those of privileged users such as root or system
administrators. |
contains 1 rule |
Set Interactive Session Timeout
[ref]ruleSetting the TMOUT option in /etc/profile ensures that
all user sessions will terminate based on inactivity.
The value of TMOUT should be exported and read only.
The TMOUT
setting in /etc/profile.d/autologout.sh should read as follows:
TMOUT=600
readonly TMOUT
export TMOUTRationale:Terminating an idle session within a short time period reduces
the window of opportunity for unauthorized personnel to take control of a
management session enabled on the console or console port that has been
left unattended. Identifiers:
CCE-83269-1 References:
BP28(R29), 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.11, CCI-000057, CCI-001133, CCI-002361, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-12, SC-10, AC-2(5), CM-6(a), PR.AC-7, FMT_MOF_EXT.1, 8.6.1, SRG-OS-000163-GPOS-00072, SRG-OS-000029-GPOS-00010, SLES-15-010130, 5.4.4, SV-234813r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_accounts_tmout # promote to variable
set_fact:
var_accounts_tmout: !!str 600
tags:
- always
- name: Set Interactive Session Timeout
block:
- name: Check for duplicate values
lineinfile:
path: /etc/profile.d/autologout.sh
create: true
regexp: ^\s*TMOUT=
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/profile.d/autologout.sh
lineinfile:
path: /etc/profile.d/autologout.sh
create: true
regexp: ^\s*TMOUT=
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/profile.d/autologout.sh
lineinfile:
path: /etc/profile.d/autologout.sh
create: true
regexp: ^\s*TMOUT=
line: TMOUT={{ var_accounts_tmout }}
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83269-1
- DISA-STIG-SLES-15-010130
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSSv4-8.6.1
- accounts_tmout
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Interactive Session Timeout
block:
- name: Check for duplicate values
lineinfile:
path: /etc/profile.d/autologout.sh
create: true
regexp: ^\s*readonly\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/profile.d/autologout.sh
lineinfile:
path: /etc/profile.d/autologout.sh
create: true
regexp: ^\s*readonly\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/profile.d/autologout.sh
lineinfile:
path: /etc/profile.d/autologout.sh
create: true
regexp: ^\s*readonly\s+
line: readonly TMOUT
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83269-1
- DISA-STIG-SLES-15-010130
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSSv4-8.6.1
- accounts_tmout
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Interactive Session Timeout
block:
- name: Check for duplicate values
lineinfile:
path: /etc/profile.d/autologout.sh
create: true
regexp: ^\s*export\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/profile.d/autologout.sh
lineinfile:
path: /etc/profile.d/autologout.sh
create: true
regexp: ^\s*export\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/profile.d/autologout.sh
lineinfile:
path: /etc/profile.d/autologout.sh
create: true
regexp: ^\s*export\s+
line: export TMOUT
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83269-1
- DISA-STIG-SLES-15-010130
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSSv4-8.6.1
- accounts_tmout
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set the permission for /etc/profile.d/autologout.sh
file:
path: /etc/profile.d/autologout.sh
mode: '0755'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83269-1
- DISA-STIG-SLES-15-010130
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSSv4-8.6.1
- accounts_tmout
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_accounts_tmout='600'
if [ -f /etc/profile.d/autologout.sh ]; then
if grep --silent '^\s*TMOUT' /etc/profile.d/autologout.sh ; then
sed -i -E "s/^(\s*)TMOUT\s*=\s*(\w|\$)*(.*)$/\1TMOUT=$var_accounts_tmout\3/g" /etc/profile.d/autologout.sh
fi
else
echo -e "\n# Set TMOUT to $var_accounts_tmout per security requirements" >> /etc/profile.d/autologout.sh
echo "TMOUT=$var_accounts_tmout" >> /etc/profile.d/autologout.sh
fi
if ! grep --silent '^\s*readonly TMOUT' /etc/profile.d/autologout.sh ; then
echo "readonly TMOUT" >> /etc/profile.d/autologout.sh
fi
if ! grep --silent '^\s*export TMOUT' /etc/profile.d/autologout.sh ; then
echo "export TMOUT" >> /etc/profile.d/autologout.sh
fi
chmod +x /etc/profile.d/autologout.sh
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
System Accounting with auditd
[ref]groupThe audit service provides substantial capabilities
for recording system activities. By default, the service audits about
SELinux AVC denials and certain types of security-relevant events
such as system logins, account modifications, and authentication
events performed by programs such as sudo.
Under its default configuration, auditd has modest disk space
requirements, and should not noticeably impact system performance.
NOTE: The Linux Audit daemon auditd can be configured to use
the augenrules program to read audit rules files (*.rules )
located in /etc/audit/rules.d location and compile them to create
the resulting form of the /etc/audit/audit.rules configuration file
during the daemon startup (default configuration). Alternatively, the auditd
daemon can use the auditctl utility to read audit rules from the
/etc/audit/audit.rules configuration file during daemon startup,
and load them into the kernel. The expected behavior is configured via the
appropriate ExecStartPost directive setting in the
/usr/lib/systemd/system/auditd.service configuration file.
To instruct the auditd daemon to use the augenrules program
to read audit rules (default configuration), use the following setting:
ExecStartPost=-/sbin/augenrules --load
in the /usr/lib/systemd/system/auditd.service configuration file.
In order to instruct the auditd daemon to use the auditctl
utility to read audit rules, use the following setting:
ExecStartPost=-/sbin/auditctl -R /etc/audit/audit.rules
in the /usr/lib/systemd/system/auditd.service configuration file.
Refer to [Service] section of the /usr/lib/systemd/system/auditd.service
configuration file for further details.
Government networks often have substantial auditing
requirements and auditd can be configured to meet these
requirements.
Examining some example audit records demonstrates how the Linux audit system
satisfies common requirements.
The following example from Red Hat Enterprise Linux 7 Documentation available at
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/selinux_users_and_administrators_guide/index#sect-Security-Enhanced_Linux-Fixing_Problems-Raw_Audit_Messages
shows the substantial amount of information captured in a
two typical "raw" audit messages, followed by a breakdown of the most important
fields. In this example the message is SELinux-related and reports an AVC
denial (and the associated system call) that occurred when the Apache HTTP
Server attempted to access the /var/www/html/file1 file (labeled with
the samba_share_t type):
type=AVC msg=audit(1226874073.147:96): avc: denied { getattr } for pid=2465 comm="httpd"
path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0
tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file
type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13
a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48
gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd"
exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)
msg=audit(1226874073.147:96) - The number in parentheses is the unformatted time stamp (Epoch time)
for the event, which can be converted to standard time by using the
date command.
{ getattr } - The item in braces indicates the permission that was denied.
getattr
indicates the source process was trying to read the target file's status information.
This occurs before reading files. This action is denied due to the file being
accessed having the wrong label. Commonly seen permissions include getattr ,
read , and write .
comm="httpd" - The executable that launched the process. The full path of the executable is
found in the
exe= section of the system call (SYSCALL ) message,
which in this case, is exe="/usr/sbin/httpd" .
path="/var/www/html/file1" - The path to the object (target) the process attempted to access.
scontext="unconfined_u:system_r:httpd_t:s0" - The SELinux context of the process that attempted the denied action. In
this case, it is the SELinux context of the Apache HTTP Server, which is running
in the
httpd_t domain.
tcontext="unconfined_u:object_r:samba_share_t:s0" - The SELinux context of the object (target) the process attempted to access.
In this case, it is the SELinux context of
file1 . Note: the samba_share_t
type is not accessible to processes running in the httpd_t domain.
- From the system call (
SYSCALL ) message, two items are of interest:
success=no : indicates whether the denial (AVC) was enforced or not.
success=no indicates the system call was not successful (SELinux denied
access). success=yes indicates the system call was successful - this can
be seen for permissive domains or unconfined domains, such as initrc_t
and kernel_t .
exe="/usr/sbin/httpd" : the full path to the executable that launched
the process, which in this case, is exe="/usr/sbin/httpd" .
|
contains 50 rules |
Configure auditd Rules for Comprehensive Auditing
[ref]groupThe auditd program can perform comprehensive
monitoring of system activity. This section describes recommended
configuration settings for comprehensive auditing, but a full
description of the auditing system's capabilities is beyond the
scope of this guide. The mailing list linux-audit@redhat.com exists
to facilitate community discussion of the auditing system.
The audit subsystem supports extensive collection of events, including:
- Tracing of arbitrary system calls (identified by name or number)
on entry or exit.
- Filtering by PID, UID, call success, system call argument (with
some limitations), etc.
- Monitoring of specific files for modifications to the file's
contents or metadata.
Auditing rules at startup are controlled by the file /etc/audit/audit.rules .
Add rules to it to meet the auditing requirements for your organization.
Each line in /etc/audit/audit.rules represents a series of arguments
that can be passed to auditctl and can be individually tested
during runtime. See documentation in /usr/share/doc/audit-VERSION and
in the related man pages for more details.
If copying any example audit rulesets from /usr/share/doc/audit-VERSION ,
be sure to comment out the
lines containing arch= which are not appropriate for your system's
architecture. Then review and understand the following rules,
ensuring rules are activated as needed for the appropriate
architecture.
After reviewing all the rules, reading the following sections, and
editing as needed, the new rules can be activated as follows:
$ sudo service auditd restart |
contains 41 rules |
Record Events that Modify the System's Discretionary Access Controls
[ref]groupAt a minimum, the audit system should collect file permission
changes for all users and root. Note that the "-F arch=b32" lines should be
present even on a 64 bit system. These commands identify system calls for
auditing. Even if the system is 64 bit it can still execute 32 bit system
calls. Additionally, these rules can be configured in a number of ways while
still achieving the desired effect. An example of this is that the "-S" calls
could be split up and placed on separate lines, however, this is less efficient.
Add the following to /etc/audit/audit.rules :
-a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If your system is 64 bit then these lines should be duplicated and the
arch=b32 replaced with arch=b64 as follows:
-a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod |
contains 13 rules |
Record Events that Modify the System's Discretionary Access Controls - chmod
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85693-0 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SLES-15-030290, 4.1.9, SV-234928r854238_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85693-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit chmod tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85693-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chmod for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
tags:
- CCE-85693-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chmod for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
- audit_arch == "b64"
tags:
- CCE-85693-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="chmod"
KEY="perm_mod"
SYSCALL_GROUPING="chmod fchmod fchmodat"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - chown
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85690-6 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SLES-15-030250, 4.1.9, SV-234924r854236_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85690-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit chown tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85690-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chown for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
tags:
- CCE-85690-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chown for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
- audit_arch == "b64"
tags:
- CCE-85690-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="chown"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - fchmod
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85694-8 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SLES-15-030290, 4.1.9, SV-234928r854238_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85694-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fchmod tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85694-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchmod for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85694-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchmod for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85694-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fchmod"
KEY="perm_mod"
SYSCALL_GROUPING="chmod fchmod fchmodat"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - fchmodat
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85695-5 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SLES-15-030290, 4.1.9, SV-234928r854238_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85695-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchmodat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fchmodat tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85695-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchmodat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchmodat for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmodat
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmodat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmodat
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmodat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85695-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchmodat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchmodat for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmodat
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmodat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmodat
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmodat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85695-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchmodat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fchmodat"
KEY="perm_mod"
SYSCALL_GROUPING="chmod fchmod fchmodat"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - fchown
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85721-9 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SLES-15-030250, 4.1.9, SV-234924r854236_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85721-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fchown tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85721-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchown for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85721-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchown for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85721-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fchown"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - fchownat
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85692-2 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SLES-15-030250, 4.1.9, SV-234924r854236_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85692-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchownat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fchownat tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85692-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchownat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchownat for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchownat
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchownat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchownat
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchownat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85692-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchownat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchownat for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchownat
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchownat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchownat
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchownat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85692-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fchownat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fchownat"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - fremovexattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85686-4 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(a), AU-12.1(ii), AU-12(c), AU-12.1(iv), AU-3, AU-3.1, MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000499-CTR-001255, SLES-15-030190, 4.1.9, SV-234918r854234_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85686-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fremovexattr tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85686-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fremovexattr for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85686-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fremovexattr for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85686-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fremovexattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - fsetxattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85688-0 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(a), AU-12.1(ii), AU-12(c), AU-12.1(iv), AU-3, AU-3.1, MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, SLES-15-030190, 4.1.9, SV-234918r854234_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85688-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fsetxattr tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85688-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fsetxattr for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85688-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fsetxattr for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85688-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_fsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fsetxattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - lchown
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85691-4 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SLES-15-030250, 4.1.9, SV-234924r854236_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85691-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_lchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit lchown tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85691-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_lchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lchown for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of lchown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of lchown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
tags:
- CCE-85691-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_lchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lchown for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of lchown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of lchown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
- audit_arch == "b64"
tags:
- CCE-85691-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_lchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="lchown"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - lremovexattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85685-6 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, SLES-15-030190, 4.1.9, SV-234918r854234_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85685-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_lremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit lremovexattr tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85685-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_lremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lremovexattr for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85685-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_lremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lremovexattr for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85685-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_lremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="lremovexattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - lsetxattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85689-8 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(a), AU-12.1(ii), AU-12(c), AU-12.1(iv), AU-3, AU-3.1, MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, SLES-15-030190, 4.1.9, SV-234918r854234_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85689-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_lsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit lsetxattr tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85689-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_lsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lsetxattr for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85689-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_lsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lsetxattr for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85689-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_lsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="lsetxattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - removexattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured to use the augenrules
program to read audit rules during daemon startup (the default), add the
following line to a file with suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85684-9 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(a), AU-12.1(ii), AU-12(c), AU-12.1(iv), AU-3, AU-3.1, MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, SLES-15-030190, 4.1.9, SV-234918r854234_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85684-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_removexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit removexattr tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85684-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_removexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for removexattr for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85684-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_removexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for removexattr for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85684-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_removexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="removexattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Discretionary Access Controls - setxattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85687-2 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000466-GPOS-00210, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SLES-15-030190, 4.1.9, SV-234918r854234_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85687-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_setxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit setxattr tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85687-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_setxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for setxattr for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85687-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_setxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for setxattr for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85687-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_dac_modification_setxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="setxattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record File Deletion Events by User
[ref]groupAt a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete |
contains 5 rules |
Ensure auditd Collects File Deletion Events by User - rename
[ref]ruleAt a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete Rationale:Auditing file deletions will create an audit trail for files that are removed
from the system. The audit trail could aid in system troubleshooting, as well as, detecting
malicious processes that attempt to delete log files to conceal their presence. Identifiers:
CCE-85768-0 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, 4.1.13 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85768-0
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit rename tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85768-0
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for rename for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of rename in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of rename in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
tags:
- CCE-85768-0
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for rename for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of rename in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of rename in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
- audit_arch == "b64"
tags:
- CCE-85768-0
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="rename"
KEY="delete"
SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure auditd Collects File Deletion Events by User - renameat
[ref]ruleAt a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete Rationale:Auditing file deletions will create an audit trail for files that are removed
from the system. The audit trail could aid in system troubleshooting, as well as, detecting
malicious processes that attempt to delete log files to conceal their presence. Identifiers:
CCE-85769-8 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, 4.1.13 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85769-8
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit renameat tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85769-8
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for renameat for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of renameat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of renameat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85769-8
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for renameat for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of renameat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of renameat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85769-8
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="renameat"
KEY="delete"
SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure auditd Collects File Deletion Events by User - rmdir
[ref]ruleAt a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S rmdir -F auid>=1000 -F auid!=unset -F key=delete Rationale:Auditing file deletions will create an audit trail for files that are removed
from the system. The audit trail could aid in system troubleshooting, as well as, detecting
malicious processes that attempt to delete log files to conceal their presence. Identifiers:
CCE-85770-6 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85770-6
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_rmdir
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit rmdir tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85770-6
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_rmdir
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for rmdir for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- rmdir
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of rmdir in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- rmdir
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of rmdir in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
tags:
- CCE-85770-6
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_rmdir
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for rmdir for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- rmdir
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of rmdir in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- rmdir
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of rmdir in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
- audit_arch == "b64"
tags:
- CCE-85770-6
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_rmdir
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="rmdir"
KEY="delete"
SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure auditd Collects File Deletion Events by User - unlink
[ref]ruleAt a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S unlink -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S unlink -F auid>=1000 -F auid!=unset -F key=delete Rationale:Auditing file deletions will create an audit trail for files that are removed
from the system. The audit trail could aid in system troubleshooting, as well as, detecting
malicious processes that attempt to delete log files to conceal their presence. Identifiers:
CCE-85771-4 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, 4.1.13 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85771-4
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit unlink tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85771-4
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlink for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlink in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlink in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
tags:
- CCE-85771-4
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlink for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlink in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlink in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- not ( ansible_architecture == "aarch64" )
- audit_arch == "b64"
tags:
- CCE-85771-4
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="unlink"
KEY="delete"
SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure auditd Collects File Deletion Events by User - unlinkat
[ref]ruleAt a minimum, the audit system should collect file deletion events
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete Rationale:Auditing file deletions will create an audit trail for files that are removed
from the system. The audit trail could aid in system troubleshooting, as well as, detecting
malicious processes that attempt to delete log files to conceal their presence. Identifiers:
CCE-85772-2 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, 4.1.13 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85772-2
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit unlinkat tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85772-2
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlinkat for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlinkat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlinkat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85772-2
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlinkat for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlinkat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
set_fact: audit_file="/etc/audit/rules.d/delete.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- unlink
- unlinkat
- rename
- renameat
- rmdir
- name: Check existence of unlinkat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=delete
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85772-2
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_file_deletion_events_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="unlinkat"
KEY="delete"
SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Attempts to Alter Logon and Logout Events
[ref]groupThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
-w /var/log/faillock -p wa -k logins
-w /var/log/lastlog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
-w /var/log/faillock -p wa -k logins
-w /var/log/lastlog -p wa -k logins |
contains 3 rules |
Record Attempts to Alter Logon and Logout Events - faillock
[ref]ruleThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/faillock -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/faillock -p wa -k logins Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-91449-9 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, 10.2.1.3, SRG-OS-000392-GPOS-00172, SRG-OS-000470-GPOS-00214, SRG-OS-000473-GPOS-00218, SRG-APP-000503-CTR-001275, SRG-APP-000506-CTR-001290, 4.1.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-91449-9
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: XCCDF Value var_accounts_passwords_pam_faillock_dir # promote to variable
set_fact:
var_accounts_passwords_pam_faillock_dir: !!str /var/log/faillock
tags:
- always
- name: Check if watch rule for {{ var_accounts_passwords_pam_faillock_dir }} already
exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+{{ var_accounts_passwords_pam_faillock_dir }}\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91449-9
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key logins
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)logins$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-91449-9
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/logins.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/logins.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-91449-9
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-91449-9
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for {{ var_accounts_passwords_pam_faillock_dir }} in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w {{ var_accounts_passwords_pam_faillock_dir }} -p wa -k logins
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-91449-9
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for {{ var_accounts_passwords_pam_faillock_dir }} already
exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+{{ var_accounts_passwords_pam_faillock_dir }}\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91449-9
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for {{ var_accounts_passwords_pam_faillock_dir }} in /etc/audit/audit.rules
lineinfile:
line: -w {{ var_accounts_passwords_pam_faillock_dir }} -p wa -k logins
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-91449-9
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_faillock
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
var_accounts_passwords_pam_faillock_dir='/var/log/faillock'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+${var_accounts_passwords_pam_faillock_dir}" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+${var_accounts_passwords_pam_faillock_dir} $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+${var_accounts_passwords_pam_faillock_dir}$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w ${var_accounts_passwords_pam_faillock_dir} -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+${var_accounts_passwords_pam_faillock_dir}" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/logins.rules"
# If the logins.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+${var_accounts_passwords_pam_faillock_dir}" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+${var_accounts_passwords_pam_faillock_dir} $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+${var_accounts_passwords_pam_faillock_dir}$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w ${var_accounts_passwords_pam_faillock_dir} -p wa -k logins" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Attempts to Alter Logon and Logout Events - lastlog
[ref]ruleThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/lastlog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/lastlog -p wa -k logins Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-85598-1 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, 10.2.1.3, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218, SRG-OS-000470-GPOS-00214, SRG-APP-000495-CTR-001235, SRG-APP-000503-CTR-001275, SRG-APP-000506-CTR-001290, SLES-15-030480, 4.1.7, SV-234947r854254_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/lastlog already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/log/lastlog\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key logins
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)logins$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/logins.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/logins.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/lastlog in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/lastlog -p wa -k logins
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/lastlog already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/log/lastlog\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/lastlog in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/lastlog -p wa -k logins
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/lastlog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/lastlog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/lastlog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/lastlog -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/lastlog" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/logins.rules"
# If the logins.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/lastlog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/lastlog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/lastlog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/lastlog -p wa -k logins" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Attempts to Alter Logon and Logout Events - tallylog
[ref]ruleThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-85597-3 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, CCI-000126, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, 10.2.1.3, SRG-OS-000392-GPOS-00172, SRG-OS-000470-GPOS-00214, SRG-OS-000473-GPOS-00218, SRG-APP-000503-CTR-001275, SLES-15-030470, 4.1.7, SV-234946r854253_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/tallylog already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/log/tallylog\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key logins
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)logins$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/logins.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/logins.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/tallylog in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/tallylog -p wa -k logins
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/tallylog already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/log/tallylog\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/tallylog in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/tallylog -p wa -k logins
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/tallylog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/tallylog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/tallylog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/tallylog -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/tallylog" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/logins.rules"
# If the logins.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/tallylog" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/tallylog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/tallylog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/tallylog -p wa -k logins" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Records Events that Modify Date and Time Information
[ref]groupArbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time. All changes to the system
time should be audited. |
contains 5 rules |
Record attempts to alter time through adjtimex
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules
The -k option allows for the specification of a key in string form that can be
used for better reporting capability through ausearch and aureport. Multiple
system calls can be defined on the same line to save space if desired, but is
not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-85814-2 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 10.6.3, 4.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85814-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_adjtimex
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set architecture for audit tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85814-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_adjtimex
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for adjtimex for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- adjtimex
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of adjtimex in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- adjtimex
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of adjtimex in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85814-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_adjtimex
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for adjtimex for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- adjtimex
syscall_grouping:
- adjtimex
- settimeofday
- name: Check existence of adjtimex in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- adjtimex
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of adjtimex in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85814-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_adjtimex
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
# Create expected audit group and audit rule form for particular system call & architecture
if [ ${ARCH} = "b32" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
# so append it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday stime"
SYSCALL_GROUPING="adjtimex settimeofday stime"
elif [ ${ARCH} = "b64" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore don't add it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday"
SYSCALL_GROUPING="adjtimex settimeofday"
fi
OTHER_FILTERS=""
AUID_FILTERS=""
KEY="audit_time_rules"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Attempts to Alter Time Through clock_settime
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change
The -k option allows for the specification of a key in string form that can
be used for better reporting capability through ausearch and aureport.
Multiple system calls can be defined on the same line to save space if
desired, but is not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-85816-7 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 10.6.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85816-7
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_clock_settime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set architecture for audit tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85816-7
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_clock_settime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for clock_settime for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- clock_settime
syscall_grouping: []
- name: Check existence of clock_settime in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/time-change.rules
set_fact: audit_file="/etc/audit/rules.d/time-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F a0=0x0 -F
key=time-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- clock_settime
syscall_grouping: []
- name: Check existence of clock_settime in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F a0=0x0 -F
key=time-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85816-7
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_clock_settime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for clock_settime for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- clock_settime
syscall_grouping: []
- name: Check existence of clock_settime in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/time-change.rules
set_fact: audit_file="/etc/audit/rules.d/time-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F a0=0x0 -F
key=time-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- clock_settime
syscall_grouping: []
- name: Check existence of clock_settime in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F a0=0x0 -F
key=time-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85816-7
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_clock_settime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-F a0=0x0"
AUID_FILTERS=""
SYSCALL="clock_settime"
KEY="time-change"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record attempts to alter time through settimeofday
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules
The -k option allows for the specification of a key in string form that can be
used for better reporting capability through ausearch and aureport. Multiple
system calls can be defined on the same line to save space if desired, but is
not required. See an example of multiple combined syscalls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-85813-4 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 10.6.3, 4.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85813-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_settimeofday
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set architecture for audit tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85813-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_settimeofday
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for settimeofday for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- settimeofday
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of settimeofday in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- settimeofday
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of settimeofday in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85813-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_settimeofday
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for settimeofday for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- settimeofday
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of settimeofday in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- settimeofday
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of settimeofday in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85813-4
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_settimeofday
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
# Create expected audit group and audit rule form for particular system call & architecture
if [ ${ARCH} = "b32" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
# so append it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday stime"
SYSCALL_GROUPING="adjtimex settimeofday stime"
elif [ ${ARCH} = "b64" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore don't add it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday"
SYSCALL_GROUPING="adjtimex settimeofday"
fi
OTHER_FILTERS=""
AUID_FILTERS=""
KEY="audit_time_rules"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Attempts to Alter Time Through stime
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit
lookup table, the corresponding "-F arch=b64" form of this rule is not expected
to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule
form itself is sufficient for both 32 bit and 64 bit systems). If the
auditd daemon is configured to use the auditctl utility to
read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file for both 32 bit and 64 bit systems:
-a always,exit -F arch=b32 -S stime -F key=audit_time_rules
Since the 64 bit version of the "stime" system call is not defined in the audit
lookup table, the corresponding "-F arch=b64" form of this rule is not expected
to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule
form itself is sufficient for both 32 bit and 64 bit systems). The -k option
allows for the specification of a key in string form that can be used for
better reporting capability through ausearch and aureport. Multiple system
calls can be defined on the same line to save space if desired, but is not
required. See an example of multiple combined system calls:
-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-85815-9 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 10.6.3, 4.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85815-9
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_stime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for stime syscall for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- stime
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of stime in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- stime
syscall_grouping:
- adjtimex
- settimeofday
- stime
- name: Check existence of stime in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ( not ( ansible_architecture == "aarch64" ) and not ( ansible_architecture ==
"s390x" ) )
tags:
- CCE-85815-9
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- audit_rules_time_stime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ( ! ( grep -q aarch64 /proc/sys/kernel/osrelease ) && ! ( grep -q s390x /proc/sys/kernel/osrelease ) ); }; then
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
# Create expected audit group and audit rule form for particular system call & architecture
if [ ${ARCH} = "b32" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
# so append it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday stime"
SYSCALL_GROUPING="adjtimex settimeofday stime"
elif [ ${ARCH} = "b64" ]
then
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
# stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
# therefore don't add it to the list of time group system calls to be audited
SYSCALL="adjtimex settimeofday"
SYSCALL_GROUPING="adjtimex settimeofday"
fi
OTHER_FILTERS=""
AUID_FILTERS=""
KEY="audit_time_rules"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Attempts to Alter the localtime File
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the default),
add the following line to a file with suffix .rules in the directory
/etc/audit/rules.d :
-w /etc/localtime -p wa -k audit_time_rules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/localtime -p wa -k audit_time_rules
The -k option allows for the specification of a key in string form that can
be used for better reporting capability through ausearch and aureport and
should always be used.Rationale:Arbitrary changes to the system time can be used to obfuscate
nefarious activities in log files, as well as to confuse network services that
are highly dependent upon an accurate system time (such as sshd). All changes
to the system time should be audited. Identifiers:
CCE-85812-6 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 10.6.3, 10.6.3, 4.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85812-6
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- PCI-DSSv4-10.6.3
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/localtime already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/localtime\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85812-6
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- PCI-DSSv4-10.6.3
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_time_rules
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_time_rules$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85812-6
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- PCI-DSSv4-10.6.3
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_time_rules.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_time_rules.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85812-6
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- PCI-DSSv4-10.6.3
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85812-6
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- PCI-DSSv4-10.6.3
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/localtime in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/localtime -p wa -k audit_time_rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85812-6
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- PCI-DSSv4-10.6.3
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/localtime already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/localtime\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85812-6
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- PCI-DSSv4-10.6.3
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/localtime in /etc/audit/audit.rules
lineinfile:
line: -w /etc/localtime -p wa -k audit_time_rules
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85812-6
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.2.b
- PCI-DSSv4-10.6.3
- PCI-DSSv4-10.6.3
- audit_rules_time_watch_localtime
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/localtime" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/localtime $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/localtime$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/localtime -p wa -k audit_time_rules" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_time_rules.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/localtime" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_time_rules.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_time_rules.rules"
# If the audit_time_rules.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/localtime" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/localtime $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/localtime$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/localtime -p wa -k audit_time_rules" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Make the auditd Configuration Immutable
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d in order to make the auditd configuration
immutable:
-e 2
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file in order to make the auditd configuration
immutable:
-e 2
With this setting, a reboot will be required to change any audit rules.Rationale:Making the audit configuration immutable prevents accidental as
well as malicious modification of the audit rules, although it may be
problematic if legitimate changes are needed during system
operation. Identifiers:
CCE-85831-6 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO01.06, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, DSS06.02, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, 3.4.3, CCI-000162, CCI-000163, CCI-000164, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.310(a)(2)(iv), 164.312(d), 164.310(d)(2)(iii), 164.312(b), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 6.1, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, ID.SC-4, PR.AC-4, PR.DS-5, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.5.2, 10.3.2, SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-APP-000119-CTR-000245, SRG-APP-000120-CTR-000250, 4.1.17 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85831-6
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-171-3.4.3
- NIST-800-53-AC-6(9)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- audit_rules_immutable
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Collect all files from /etc/audit/rules.d with .rules extension
find:
paths: /etc/audit/rules.d/
patterns: '*.rules'
register: find_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85831-6
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-171-3.4.3
- NIST-800-53-AC-6(9)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- audit_rules_immutable
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Remove the -e option from all Audit config files
lineinfile:
path: '{{ item }}'
regexp: ^\s*(?:-e)\s+.*$
state: absent
loop: '{{ find_rules_d.files | map(attribute=''path'') | list + [''/etc/audit/audit.rules'']
}}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85831-6
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-171-3.4.3
- NIST-800-53-AC-6(9)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- audit_rules_immutable
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add Audit -e option into /etc/audit/rules.d/immutable.rules and /etc/audit/audit.rules
lineinfile:
path: '{{ item }}'
create: true
line: -e 2
mode: o-rwx
loop:
- /etc/audit/audit.rules
- /etc/audit/rules.d/immutable.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85831-6
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-171-3.4.3
- NIST-800-53-AC-6(9)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- audit_rules_immutable
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Traverse all of:
#
# /etc/audit/audit.rules, (for auditctl case)
# /etc/audit/rules.d/*.rules (for augenrules case)
#
# files to check if '-e .*' setting is present in that '*.rules' file already.
# If found, delete such occurrence since auditctl(8) manual page instructs the
# '-e 2' rule should be placed as the last rule in the configuration
find /etc/audit /etc/audit/rules.d -maxdepth 1 -type f -name '*.rules' -exec sed -i '/-e[[:space:]]\+.*/d' {} ';'
# Append '-e 2' requirement at the end of both:
# * /etc/audit/audit.rules file (for auditctl case)
# * /etc/audit/rules.d/immutable.rules (for augenrules case)
for AUDIT_FILE in "/etc/audit/audit.rules" "/etc/audit/rules.d/immutable.rules"
do
echo '' >> $AUDIT_FILE
echo '# Set the audit.rules configuration immutable per security requirements' >> $AUDIT_FILE
echo '# Reboot is required to change audit rules once this setting is applied' >> $AUDIT_FILE
echo '-e 2' >> $AUDIT_FILE
chmod o-rwx $AUDIT_FILE
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Mandatory Access Controls
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following line to a file with suffix .rules in the
directory /etc/audit/rules.d :
-w /etc/selinux/ -p wa -k MAC-policy
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/selinux/ -p wa -k MAC-policy Rationale:The system's mandatory access policy (SELinux) should not be
arbitrarily changed by anything other than administrator action. All changes to
MAC policy should be audited. Identifiers:
CCE-85830-8 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.8, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, 4.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85830-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/selinux/ already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/selinux/\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85830-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key MAC-policy
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)MAC-policy$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85830-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/MAC-policy.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/MAC-policy.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85830-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85830-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/selinux/ in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/selinux/ -p wa -k MAC-policy
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85830-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/selinux/ already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/selinux/\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85830-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/selinux/ in /etc/audit/audit.rules
lineinfile:
line: -w /etc/selinux/ -p wa -k MAC-policy
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85830-8
- CJIS-5.4.1.1
- NIST-800-171-3.1.8
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_mac_modification
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/selinux/" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/selinux/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/selinux/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/selinux/ -p wa -k MAC-policy" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/MAC-policy.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/selinux/" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/MAC-policy.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/MAC-policy.rules"
# If the MAC-policy.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/selinux/" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/selinux/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/selinux/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/selinux/ -p wa -k MAC-policy" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure auditd Collects Information on Exporting to Media (successful)
[ref]ruleAt a minimum, the audit system should collect media exportation
events for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export Rationale:The unauthorized exportation of data to external media could result in an information leak
where classified information, Privacy Act information, and intellectual property could be lost. An audit
trail should be created each time a filesystem is mounted to help identify and guard against information
loss. Identifiers:
CCE-85718-5 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000495-CTR-001235, SLES-15-030350, 4.1.12, SV-234934r854241_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85718-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030350
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_media_export
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit mount tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85718-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030350
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_media_export
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for mount for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- mount
syscall_grouping: []
- name: Check existence of mount in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- mount
syscall_grouping: []
- name: Check existence of mount in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85718-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030350
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_media_export
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for mount for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- mount
syscall_grouping: []
- name: Check existence of mount in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- mount
syscall_grouping: []
- name: Check existence of mount in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85718-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030350
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- PCI-DSSv4-10.2.1.7
- audit_rules_media_export
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="mount"
KEY="perm_mod"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify the System's Network Environment
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification Rationale:The network environment should not be modified by anything other
than administrator action. Any change to network parameters should be
audited. Identifiers:
CCE-85828-2 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.5.5, 10.3.4, 4.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set architecture for audit tasks
set_fact:
audit_arch: b64
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
== "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Remediate audit rules for network configuration for 32bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- sethostname
- setdomainname
syscall_grouping:
- sethostname
- setdomainname
- name: Check existence of sethostname, setdomainname in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
set_fact: audit_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- sethostname
- setdomainname
syscall_grouping:
- sethostname
- setdomainname
- name: Check existence of sethostname, setdomainname in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Remediate audit rules for network configuration for 64bit platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- sethostname
- setdomainname
syscall_grouping:
- sethostname
- setdomainname
- name: Check existence of sethostname, setdomainname in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
set_fact: audit_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- sethostname
- setdomainname
syscall_grouping:
- sethostname
- setdomainname
- name: Check existence of sethostname, setdomainname in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
|,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
| list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- audit_arch == "b64"
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/issue already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/issue\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/issue in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/issue -p wa -k audit_rules_networkconfig_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/issue already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/issue\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/issue in /etc/audit/audit.rules
lineinfile:
line: -w /etc/issue -p wa -k audit_rules_networkconfig_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/issue.net already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/issue.net\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/issue.net in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/issue.net already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/issue.net\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/issue.net in /etc/audit/audit.rules
lineinfile:
line: -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/hosts already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/hosts\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/hosts in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/hosts already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/hosts\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/hosts in /etc/audit/audit.rules
lineinfile:
line: -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/sysconfig/network already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/sysconfig/network\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/sysconfig/network in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/sysconfig/network already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/sysconfig/network\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/sysconfig/network in /etc/audit/audit.rules
lineinfile:
line: -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85828-2
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.5
- PCI-DSSv4-10.3.4
- audit_rules_networkconfig_modification
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS=""
SYSCALL="sethostname setdomainname"
KEY="audit_rules_networkconfig_modification"
SYSCALL_GROUPING="sethostname setdomainname"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
# Then perform the remediations for the watch rules
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/issue" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/issue$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/issue -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/issue" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
# If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/issue" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/issue$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/issue -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/issue.net" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue.net $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/issue.net$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/issue.net" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
# If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/issue.net" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue.net $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/issue.net$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/hosts" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/hosts $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/hosts$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/hosts -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/hosts" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
# If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/hosts" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/hosts $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/hosts$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/hosts -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/sysconfig/network" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sysconfig/network $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sysconfig/network$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sysconfig/network" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
# If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/sysconfig/network" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sysconfig/network $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sysconfig/network$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Attempts to Alter Process and Session Initiation Information
[ref]ruleThe audit system already collects process information for all
users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for attempted manual
edits of files involved in storing such process information:
-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-85829-0 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, 0582, 0584, 05885, 0586, 0846, 0957, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, 10.2.1.3, SRG-APP-000505-CTR-001285, 4.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/run/utmp already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/run/utmp\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key session
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)session$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/session.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/run/utmp in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/run/utmp -p wa -k session
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/run/utmp already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/run/utmp\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/run/utmp in /etc/audit/audit.rules
lineinfile:
line: -w /var/run/utmp -p wa -k session
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/btmp already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key session
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)session$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/session.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/btmp in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/btmp -p wa -k session
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/btmp already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/btmp in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/btmp -p wa -k session
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key session
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)session$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/session.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/wtmp in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/wtmp -p wa -k session
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/wtmp in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/wtmp -p wa -k session
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85829-0
- CJIS-5.4.1.1
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- PCI-DSSv4-10.2.1.3
- audit_rules_session_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/run/utmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/utmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/run/utmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/run/utmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/run/utmp" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/session.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/session.rules"
# If the session.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/run/utmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/utmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/run/utmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/run/utmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/btmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/btmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/btmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/btmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/btmp" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/session.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/session.rules"
# If the session.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/btmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/btmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/btmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/btmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/wtmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/wtmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/wtmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/wtmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/wtmp" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/session.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/session.rules"
# If the session.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/wtmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/wtmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/wtmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/wtmp -p wa -k session" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events When Privileged Executables Are Run
[ref]ruleVerify the system generates an audit record when privileged functions are executed.
If audit is using the "auditctl" tool to load the rules, run the following command:
$ sudo grep execve /etc/audit/audit.rules
If audit is using the "augenrules" tool to load the rules, run the following command:
$ sudo grep -r execve /etc/audit/rules.d
-a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k setuid
-a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k setuid
-a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k setgid
-a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k setgid
If both the "b32" and "b64" audit rules for "SUID" files are not defined, this is a finding.
If both the "b32" and "b64" audit rules for "SGID" files are not defined, this is a finding.Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have
compromised information system accounts, is a serious and ongoing concern
and can have significant adverse impacts on organizations. Auditing the use
of privileged functions is one way to detect such misuse and identify the
risk from insider threats and the advanced persistent threat. Identifiers:
CCE-85611-2 References:
CCI-001814, CCI-001882, CCI-001889, CCI-001880, CCI-001881, CCI-001878, CCI-001879, CCI-001875, CCI-001877, CCI-001914, CCI-002233, CCI-002234, CM-5(1), AU-7(a), AU-7(b), AU-8(b), AU-12(3), AC-6(9), 10.2.1.2, SRG-OS-000326-GPOS-00126, SRG-OS-000327-GPOS-00127, SRG-APP-000343-CTR-000780, SRG-APP-000381-CTR-000905, SLES-15-030640, SV-234963r854263_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- PCI-DSSv4-10.2.1.2
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Service facts
ansible.builtin.service_facts: null
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- PCI-DSSv4-10.2.1.2
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the rules script being used
ansible.builtin.command: grep '^ExecStartPost' /usr/lib/systemd/system/auditd.service
register: check_rules_scripts_result
changed_when: false
failed_when: false
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- PCI-DSSv4-10.2.1.2
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set suid_audit_rules fact
ansible.builtin.set_fact:
suid_audit_rules:
- rule: -a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k setgid
regex: ^[\s]*-a[\s]+always,exit[\s]+-F[\s]+arch=b32[\s]+-S[\s]+execve[\s]+-C[\s]+gid!=egid[\s]+-F[\s]+egid=0[\s]+(?:-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
- rule: -a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k setgid
regex: ^[\s]*-a[\s]+always,exit[\s]+-F[\s]+arch=b64[\s]+-S[\s]+execve[\s]+-C[\s]+gid!=egid[\s]+-F[\s]+egid=0[\s]+(?:-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
- rule: -a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k setuid
regex: ^[\s]*-a[\s]+always,exit[\s]+-F[\s]+arch=b32[\s]+-S[\s]+execve[\s]+-C[\s]+uid!=euid[\s]+-F[\s]+euid=0[\s]+(?:-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
- rule: -a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k setuid
regex: ^[\s]*-a[\s]+always,exit[\s]+-F[\s]+arch=b64[\s]+-S[\s]+execve[\s]+-C[\s]+uid!=euid[\s]+-F[\s]+euid=0[\s]+(?:-k[\s]+|-F[\s]+key=)[\S]+[\s]*$
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- PCI-DSSv4-10.2.1.2
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Update /etc/audit/rules.d/privileged.rules to audit privileged functions
ansible.builtin.lineinfile:
path: /etc/audit/rules.d/privileged.rules
line: '{{ item.rule }}'
regexp: '{{ item.regex }}'
create: true
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"auditd.service" in ansible_facts.services'
- '"augenrules" in check_rules_scripts_result.stdout'
register: augenrules_audit_rules_privilege_function_update_result
with_items: '{{ suid_audit_rules }}'
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- PCI-DSSv4-10.2.1.2
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Update Update /etc/audit/audit.rules to audit privileged functions
ansible.builtin.lineinfile:
path: /etc/audit/audit.rules
line: '{{ item.rule }}'
regexp: '{{ item.regex }}'
create: true
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"auditd.service" in ansible_facts.services'
- '"auditctl" in check_rules_scripts_result.stdout'
register: auditctl_audit_rules_privilege_function_update_result
with_items: '{{ suid_audit_rules }}'
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- PCI-DSSv4-10.2.1.2
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Restart auditd.service
ansible.builtin.systemd:
name: auditd.service
state: restarted
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (augenrules_audit_rules_privilege_function_update_result.changed or auditctl_audit_rules_privilege_function_update_result.changed)
- ansible_facts.services["auditd.service"].state == "running"
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- PCI-DSSv4-10.2.1.2
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-C uid!=euid -F euid=0"
AUID_FILTERS=""
SYSCALL="execve"
KEY="setuid"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-C gid!=egid -F egid=0"
AUID_FILTERS=""
SYSCALL="execve"
KEY="setgid"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
# A syscall was not found in the candidate rule
all_syscalls_found=1
}
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [ "${#candidate_rules[@]}" -gt 0 ]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [ "${#syscall_a[@]}" -gt 0 ]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
}
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure auditd Collects System Administrator Actions
[ref]ruleAt a minimum, the audit system should collect administrator actions
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the default),
add the following line to a file with suffix .rules in the directory
/etc/audit/rules.d :
-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions Rationale:The actions taken by system administrators should be audited to keep a record
of what was executed on the system, as well as, for accountability purposes. Identifiers:
CCE-85679-9 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AU-3, AU-3.1, AU-12(a), AU-12.1(ii), AU-12.1(iv), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.2, Req-10.2.5.b, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000026-CTR-000070, SRG-APP-000027-CTR-000075, SRG-APP-000028-CTR-000080, SRG-APP-000291-CTR-000675, SRG-APP-000292-CTR-000680, SRG-APP-000293-CTR-000685, SRG-APP-000294-CTR-000690, SRG-APP-000319-CTR-000745, SRG-APP-000320-CTR-000750, SRG-APP-000509-CTR-001305, SLES-15-030140, 4.1.14, SV-234913r854230_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/sudoers already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/sudoers\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/sudoers in /etc/audit/audit.rules
lineinfile:
line: -w /etc/sudoers -p wa -k actions
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/sudoers already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/sudoers\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key actions
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)actions$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/actions.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/actions.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/sudoers in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/sudoers -p wa -k actions
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/sudoers.d/ already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/sudoers.d/\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/sudoers.d/ in /etc/audit/audit.rules
lineinfile:
line: -w /etc/sudoers.d/ -p wa -k actions
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /etc/sudoers.d/ already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/sudoers.d/\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key actions
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)actions$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/actions.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/actions.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /etc/sudoers.d/ in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/sudoers.d/ -p wa -k actions
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.5
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers -p wa -k actions" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/actions.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sudoers" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/actions.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/actions.rules"
# If the actions.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers -p wa -k actions" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers.d/" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers.d/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers.d/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers.d/ -p wa -k actions" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/actions.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sudoers.d/" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/actions.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/actions.rules"
# If the actions.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers.d/" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers.d/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers.d/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers.d/ -p wa -k actions" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify User/Group Information - /etc/group
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-85578-3 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275, SLES-15-030010, 4.1.4, SV-234900r854217_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/group already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/group\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_usergroup_modification.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/group in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/group -p wa -k audit_rules_usergroup_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/group already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/group\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/group in /etc/audit/audit.rules
lineinfile:
line: -w /etc/group -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/group" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/group $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/group$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/group -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/group" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/group" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/group $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/group$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/group -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify User/Group Information - /etc/gshadow
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-85580-9 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275, SLES-15-030040, 4.1.4, SV-234903r854220_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/gshadow already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/gshadow\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_usergroup_modification.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/gshadow in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/gshadow already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/gshadow\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/gshadow in /etc/audit/audit.rules
lineinfile:
line: -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/gshadow" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/gshadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/gshadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/gshadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/gshadow" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/gshadow" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/gshadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/gshadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/gshadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify User/Group Information - /etc/security/opasswd
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-85728-4 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4).1(i&ii), AU-12.1(iv), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000503-CTR-001275, SLES-15-030030, 4.1.4, SV-234902r854219_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/security/opasswd already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/security/opasswd\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_usergroup_modification.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/security/opasswd in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/security/opasswd already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/security/opasswd\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/security/opasswd in /etc/audit/audit.rules
lineinfile:
line: -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/security/opasswd" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/security/opasswd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/security/opasswd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/security/opasswd" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/security/opasswd" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/security/opasswd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/security/opasswd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify User/Group Information - /etc/passwd
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/passwd -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-85577-5 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-OS-000274-GPOS-00104, SRG-OS-000275-GPOS-00105, SRG-OS-000276-GPOS-00106, SRG-OS-000277-GPOS-00107, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275, SLES-15-030000, 4.1.4, SV-234899r854216_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/passwd already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/passwd\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_usergroup_modification.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/passwd in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/passwd -p wa -k audit_rules_usergroup_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/passwd already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/passwd\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/passwd in /etc/audit/audit.rules
lineinfile:
line: -w /etc/passwd -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/passwd" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/passwd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/passwd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/passwd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/passwd" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/passwd" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/passwd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/passwd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/passwd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Events that Modify User/Group Information - /etc/shadow
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/shadow -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-85579-1 References:
BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275, SLES-15-030020, 4.1.4, SV-234901r854218_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/shadow already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/etc/shadow\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
for the rule
set_fact:
all_files:
- /etc/audit/rules.d/audit_rules_usergroup_modification.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/shadow in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/shadow -p wa -k audit_rules_usergroup_modification
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /etc/shadow already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/etc/shadow\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /etc/shadow in /etc/audit/audit.rules
lineinfile:
line: -w /etc/shadow -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- PCI-DSSv4-10.2.1.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/shadow" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/shadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/shadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/shadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/shadow" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
# If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/etc/shadow" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/shadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/shadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/shadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Record Attempts to perform maintenance activities
[ref]ruleThe SUSE Linux Enterprise 15 operating system must generate audit records for
privileged activities, nonlocal maintenance, diagnostic sessions and
other system-level access.
Verify the operating system audits activities performed during nonlocal
maintenance and diagnostic sessions. Run the following command:
$ sudo auditctl -l | grep sudo.log
-w /var/log/sudo.log -p wa -k maintenance Rationale:If events associated with nonlocal administrative access or diagnostic
sessions are not logged, a major tool for assessing and investigating
attacks would not be available.
This requirement addresses auditing-related issues associated with
maintenance tools used specifically for diagnostic and repair actions
on organizational information systems.
Nonlocal maintenance and diagnostic activities are those activities
conducted by individuals communicating through a network, either an
external network (e.g., the internet) or an internal network. Local
maintenance and diagnostic activities are those activities carried
out by individuals physically present at the information system or
information system component and not communicating across a network
connection.
This requirement applies to hardware/software diagnostic test
equipment or tools. This requirement does not cover hardware/software
components that may support information system maintenance, yet are a
part of the system, for example, the software implementing "ping,"
"ls," "ipconfig," or the hardware and software implementing the
monitoring port of an Ethernet switch. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-92551-1
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.4
- audit_sudo_log_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/sudo.log already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/log/sudo.log\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-92551-1
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.4
- audit_sudo_log_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key logins
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)logins$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-92551-1
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.4
- audit_sudo_log_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/logins.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/logins.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-92551-1
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.4
- audit_sudo_log_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-92551-1
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.4
- audit_sudo_log_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/sudo.log in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/sudo.log -p wa -k logins
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-92551-1
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.4
- audit_sudo_log_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/sudo.log already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/log/sudo.log\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-92551-1
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.4
- audit_sudo_log_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/sudo.log in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/sudo.log -p wa -k logins
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-92551-1
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- PCI-DSSv4-10.2.1.4
- audit_sudo_log_events
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/sudo.log" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/sudo.log $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/sudo.log$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/sudo.log -p wa -k logins" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/sudo.log" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/logins.rules"
# If the logins.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "^[\s]*-w[\s]+/var/log/sudo.log" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/sudo.log $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/sudo.log$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/sudo.log -p wa -k logins" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
System Audit Logs Must Be Owned By Root
[ref]ruleAll audit logs must be owned by root user and group. By default, the path for audit log is /var/log/audit/ .
To properly set the owner of /var/log/audit , run the command:
$ sudo chown root /var/log/audit
To properly set the owner of /var/log/audit/* , run the command:
$ sudo chown root /var/log/audit/* Rationale:Unauthorized disclosure of audit records can reveal system and configuration data to
attackers, thus compromising its confidentiality. Identifiers:
CCE-85810-0 References:
1, 11, 12, 13, 14, 15, 16, 18, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO01.06, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, DSS06.02, MEA02.01, 3.3.1, CCI-000162, CCI-000163, CCI-000164, CCI-001314, 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 6.1, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), AU-9(4), DE.AE-3, DE.AE-5, PR.AC-4, PR.DS-5, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.5.1, 10.3.2, SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-APP-000118-CTR-000240 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
if LC_ALL=C grep -m 1 -q ^log_group /etc/audit/auditd.conf; then
GROUP=$(awk -F "=" '/log_group/ {print $2}' /etc/audit/auditd.conf | tr -d ' ')
if ! [ "${GROUP}" == 'root' ] ; then
chown root:${GROUP} /var/log/audit
chown root:${GROUP} /var/log/audit/audit.log*
else
chown root:root /var/log/audit
chown root:root /var/log/audit/audit.log*
fi
else
chown root:root /var/log/audit
chown root:root /var/log/audit/audit.log*
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
System Audit Logs Must Have Mode 0640 or Less Permissive
[ref]rule
If log_group in /etc/audit/auditd.conf is set to a group other than the
root
group account, change the mode of the audit log files with the following command:
$ sudo chmod 0640 audit_file
Otherwise, change the mode of the audit log files with the following command:
$ sudo chmod 0600 audit_file Rationale:If users can write to audit logs, audit trails can be modified or destroyed. Identifiers:
CCE-85811-8 References:
1, 11, 12, 13, 14, 15, 16, 18, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO01.06, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, DSS06.02, MEA02.01, 3.3.1, CCI-000162, CCI-000163, CCI-000164, CCI-001314, 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 6.1, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), AU-9(4), DE.AE-3, DE.AE-5, PR.AC-4, PR.DS-5, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.5, 10.3.1, SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-OS-000206-GPOS-00084, SRG-APP-000118-CTR-000240 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85811-8
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-6(1)
- NIST-800-53-AU-9(4)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5
- PCI-DSSv4-10.3.1
- file_permissions_var_log_audit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Get audit log files
command: grep -iw ^log_file /etc/audit/auditd.conf
failed_when: false
register: log_file_exists
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85811-8
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-6(1)
- NIST-800-53-AU-9(4)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5
- PCI-DSSv4-10.3.1
- file_permissions_var_log_audit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Parse log file line
command: awk -F '=' '/^log_file/ {print $2}' /etc/audit/auditd.conf
register: log_file_line
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (log_file_exists.stdout | length > 0)
tags:
- CCE-85811-8
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-6(1)
- NIST-800-53-AU-9(4)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5
- PCI-DSSv4-10.3.1
- file_permissions_var_log_audit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set default log_file if not set
set_fact:
log_file: /var/log/audit/audit.log
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (log_file_exists is undefined) or (log_file_exists.stdout | length == 0)
tags:
- CCE-85811-8
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-6(1)
- NIST-800-53-AU-9(4)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5
- PCI-DSSv4-10.3.1
- file_permissions_var_log_audit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set log_file from log_file_line if not set already
set_fact:
log_file: '{{ log_file_line.stdout | trim }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (log_file_line.stdout is defined) and (log_file_line.stdout | length > 0)
tags:
- CCE-85811-8
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-6(1)
- NIST-800-53-AU-9(4)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5
- PCI-DSSv4-10.3.1
- file_permissions_var_log_audit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Get log files group
command: grep -m 1 ^log_group /etc/audit/auditd.conf
failed_when: false
register: log_group_line
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85811-8
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-6(1)
- NIST-800-53-AU-9(4)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5
- PCI-DSSv4-10.3.1
- file_permissions_var_log_audit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Parse log group line
command: awk -F '=' '/log_group/ {print $2}' /etc/audit/auditd.conf
register: log_group
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (log_group_line.stdout | length > 0)
tags:
- CCE-85811-8
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-6(1)
- NIST-800-53-AU-9(4)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5
- PCI-DSSv4-10.3.1
- file_permissions_var_log_audit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Apply mode to log file when group root
file:
path: '{{ log_file }}'
mode: (( log_group is defined ) and ( ( log_group.stdout | trim ) == 'root' ))
| ternary( '0600', '0640')
failed_when: false
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85811-8
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-6(1)
- NIST-800-53-AU-9(4)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5
- PCI-DSSv4-10.3.1
- file_permissions_var_log_audit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: List all log file backups
find:
path: '{{ log_file | dirname }}'
patterns: '{{ log_file | basename }}.*'
register: backup_files
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85811-8
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-6(1)
- NIST-800-53-AU-9(4)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5
- PCI-DSSv4-10.3.1
- file_permissions_var_log_audit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Apply mode to log file when group not root
file:
path: '{{ item }}'
mode: (( log_group is defined ) and ( ( log_group.stdout | trim ) == 'root' )) |
ternary( '0400', '0440')
loop: '{{ backup_files.files| map(attribute=''path'') | list }}'
failed_when: false
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85811-8
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-6(1)
- NIST-800-53-AU-9(4)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5
- PCI-DSSv4-10.3.1
- file_permissions_var_log_audit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
if LC_ALL=C grep -iw ^log_file /etc/audit/auditd.conf; then
FILE=$(awk -F "=" '/^log_file/ {print $2}' /etc/audit/auditd.conf | tr -d ' ')
else
FILE="/var/log/audit/audit.log"
fi
if LC_ALL=C grep -m 1 -q ^log_group /etc/audit/auditd.conf; then
GROUP=$(awk -F "=" '/log_group/ {print $2}' /etc/audit/auditd.conf | tr -d ' ')
if ! [ "${GROUP}" == 'root' ] ; then
chmod 0640 $FILE
chmod 0440 $FILE.*
else
chmod 0600 $FILE
chmod 0400 $FILE.*
fi
else
chmod 0600 $FILE
chmod 0400 $FILE.*
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Configure auditd Data Retention
[ref]groupThe audit system writes data to /var/log/audit/audit.log . By default,
auditd rotates 5 logs by size (6MB), retaining a maximum of 30MB of
data in total, and refuses to write entries when the disk is too
full. This minimizes the risk of audit data filling its partition
and impacting other services. This also minimizes the risk of the audit
daemon temporarily disabling the system if it cannot write audit log (which
it can be configured to do).
For a busy
system or a system which is thoroughly auditing system activity, the default settings
for data retention may be
insufficient. The log file size needed will depend heavily on what types
of events are being audited. First configure auditing to log all the events of
interest. Then monitor the log size manually for awhile to determine what file
size will allow you to keep the required data for the correct time period.
Using a dedicated partition for /var/log/audit prevents the
auditd logs from disrupting system functionality if they fill, and,
more importantly, prevents other activity in /var from filling the
partition and stopping the audit trail. (The audit logs are size-limited and
therefore unlikely to grow without bound unless configured to do so.) Some
machines may have requirements that no actions occur which cannot be audited.
If this is the case, then auditd can be configured to halt the machine
if it runs out of space. Note: Since older logs are rotated,
configuring auditd this way does not prevent older logs from being
rotated away before they can be viewed.
If your system is configured to halt when logging cannot be performed, make
sure this can never happen under normal circumstances! Ensure that
/var/log/audit is on its own partition, and that this partition is
larger than the maximum amount of data auditd will retain
normally. |
contains 4 rules |
Configure auditd to use audispd's syslog plugin
[ref]ruleTo configure the auditd service to use the
syslog plug-in of the audispd audit event multiplexor, set
the active line in /etc/audit/plugins.d/syslog.conf to yes .
Restart the auditd service:
$ sudo service auditd restart Rationale:The auditd service does not include the ability to send audit
records to a centralized server for management directly. It does, however,
include a plug-in for audit event multiplexor (audispd) to pass audit records
to the local syslog server. Identifiers:
CCE-85779-7 References:
1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, CCI-000136, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(B), 164.308(a)(5)(ii)(C), 164.308(a)(6)(ii), 164.308(a)(8), 164.310(d)(2)(iii), 164.312(b), 164.314(a)(2)(i)(C), 164.314(a)(2)(iii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, AU-4(1), CM-6(a), DE.AE-3, DE.AE-5, PR.PT-1, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.3, 10.3.3, SRG-OS-000479-GPOS-00224, SRG-OS-000342-GPOS-00133 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85779-7
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AU-4(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.3
- PCI-DSSv4-10.3.3
- auditd_audispd_syslog_plugin_activated
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Enable syslog plugin
lineinfile:
dest: /etc/audit/plugins.d/syslog.conf
regexp: ^active
line: active = yes
create: true
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85779-7
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AU-4(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.3
- PCI-DSSv4-10.3.3
- auditd_audispd_syslog_plugin_activated
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
var_syslog_active="yes"
AUDISP_SYSLOGCONFIG=/etc/audit/plugins.d/syslog.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^active")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_syslog_active"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^active\\>" "$AUDISP_SYSLOGCONFIG"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^active\\>.*/$escaped_formatted_output/gi" "$AUDISP_SYSLOGCONFIG"
else
if [[ -s "$AUDISP_SYSLOGCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDISP_SYSLOGCONFIG" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDISP_SYSLOGCONFIG"
fi
cce="CCE-85779-7"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "$AUDISP_SYSLOGCONFIG" >> "$AUDISP_SYSLOGCONFIG"
printf '%s\n' "$formatted_output" >> "$AUDISP_SYSLOGCONFIG"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Configure auditd admin_space_left Action on Low Disk Space
[ref]ruleThe auditd service can be configured to take an action
when disk space is running low but prior to running out of space completely.
Edit the file /etc/audit/auditd.conf . Add or modify the following line,
substituting ACTION appropriately:
admin_space_left_action = ACTION
Set this value to single to cause the system to switch to single user
mode for corrective action. Acceptable values also include suspend and
halt . For certain systems, the need for availability
outweighs the need to log all actions, and a different setting should be
determined. Details regarding all possible values for ACTION are described in the
auditd.conf man page.Rationale:Administrators should be made aware of an inability to record
audit records. If a separate partition or logical volume of adequate size
is used, running low on space for audit records should never occur. Identifiers:
CCE-85824-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, CCI-000140, CCI-001343, CCI-001855, 164.312(a)(2)(ii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7, 10.5.1, SRG-OS-000343-GPOS-00134, 4.1.2.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85824-1
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- PCI-DSSv4-10.5.1
- auditd_data_retention_admin_space_left_action
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_auditd_admin_space_left_action # promote to variable
set_fact:
var_auditd_admin_space_left_action: !!str single
tags:
- always
- name: Configure auditd admin_space_left Action on Low Disk Space
lineinfile:
dest: /etc/audit/auditd.conf
line: admin_space_left_action = {{ var_auditd_admin_space_left_action }}
regexp: ^\s*admin_space_left_action\s*=\s*.*$
state: present
create: true
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85824-1
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- PCI-DSSv4-10.5.1
- auditd_data_retention_admin_space_left_action
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
var_auditd_admin_space_left_action='single'
AUDITCONFIG=/etc/audit/auditd.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^admin_space_left_action")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_admin_space_left_action"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^admin_space_left_action\\>" "$AUDITCONFIG"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^admin_space_left_action\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
else
if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
fi
cce="CCE-85824-1"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "$AUDITCONFIG" >> "$AUDITCONFIG"
printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Configure auditd space_left on Low Disk Space
[ref]ruleThe auditd service can be configured to take an action
when disk space is running low but prior to running out of space completely.
Edit the file /etc/audit/auditd.conf . Add or modify the following line,
substituting SIZE_in_MB appropriately:
space_left = SIZE_in_MB
Set this value to the appropriate size in Megabytes cause the system to
notify the user of an issue.Rationale:Notifying administrators of an impending disk space problem may allow them to
take corrective action prior to any disruption. Identifiers:
CCE-85616-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, CCI-001855, 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7, 10.5.1, SRG-OS-000343-GPOS-00134, SLES-15-030700, SV-234969r877389_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85616-1
- DISA-STIG-SLES-15-030700
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- PCI-DSSv4-10.5.1
- auditd_data_retention_space_left
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_auditd_space_left # promote to variable
set_fact:
var_auditd_space_left: !!str 100
tags:
- always
- name: Configure auditd space_left on Low Disk Space
lineinfile:
dest: /etc/audit/auditd.conf
line: space_left = {{ var_auditd_space_left }}
regexp: ^\s*space_left\s*=\s*.*$
state: present
create: true
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85616-1
- DISA-STIG-SLES-15-030700
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- PCI-DSSv4-10.5.1
- auditd_data_retention_space_left
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
var_auditd_space_left='100'
grep -q "^space_left[[:space:]]*=.*$" /etc/audit/auditd.conf && \
sed -i "s/^space_left[[:space:]]*=.*$/space_left = $var_auditd_space_left/g" /etc/audit/auditd.conf || \
echo "space_left = $var_auditd_space_left" >> /etc/audit/auditd.conf
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Configure auditd space_left Action on Low Disk Space
[ref]ruleThe auditd service can be configured to take an action
when disk space starts to run low.
Edit the file /etc/audit/auditd.conf . Modify the following line,
substituting ACTION appropriately:
space_left_action = ACTION
Possible values for ACTION are described in the auditd.conf man page.
These include:
syslog email exec suspend single halt
Set this to email (instead of the default,
which is suspend ) as it is more likely to get prompt attention. Acceptable values
also include suspend , single , and halt .Rationale:Notifying administrators of an impending disk space problem may
allow them to take corrective action prior to any disruption. Identifiers:
CCE-85823-3 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, CCI-001855, 164.312(a)(2)(ii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7, 10.5.1, SRG-OS-000343-GPOS-00134, 4.1.2.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85823-3
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- PCI-DSSv4-10.5.1
- auditd_data_retention_space_left_action
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_auditd_space_left_action # promote to variable
set_fact:
var_auditd_space_left_action: !!str email
tags:
- always
- name: Configure auditd space_left Action on Low Disk Space
lineinfile:
dest: /etc/audit/auditd.conf
line: space_left_action = {{ var_auditd_space_left_action }}
regexp: ^\s*space_left_action\s*=\s*.*$
state: present
create: true
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85823-3
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- PCI-DSSv4-10.5.1
- auditd_data_retention_space_left_action
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then
var_auditd_space_left_action='email'
#
# If space_left_action present in /etc/audit/auditd.conf, change value
# to var_auditd_space_left_action, else
# add "space_left_action = $var_auditd_space_left_action" to /etc/audit/auditd.conf
#
AUDITCONFIG=/etc/audit/auditd.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^space_left_action")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_space_left_action"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^space_left_action\\>" "$AUDITCONFIG"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^space_left_action\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
else
if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
fi
cce="CCE-85823-3"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "$AUDITCONFIG" >> "$AUDITCONFIG"
printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure the default plugins for the audit dispatcher are Installed
[ref]ruleThe audit-audispd-plugins package should be installed. Rationale:Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity. Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_audit-audispd-plugins
class install_audit-audispd-plugins {
package { 'audit-audispd-plugins':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "audit-audispd-plugins"
version = "*"
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure audit-audispd-plugins is installed
package:
name: audit-audispd-plugins
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85613-8
- DISA-STIG-SLES-15-030670
- PCI-DSS-Req-10.5.3
- PCI-DSSv4-10.3.3
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_audit-audispd-plugins_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "audit-audispd-plugins"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure the audit Subsystem is Installed
[ref]ruleThe audit package should be installed. Rationale:The auditd service is an access monitoring and accounting daemon, watching system calls to audit any access, in comparison with potential local access control policy such as SELinux policy. Identifiers:
CCE-85612-0 References:
BP28(R33), BP28(R73), CCI-000130, CCI-000131, CCI-000132, CCI-000133, CCI-000134, CCI-000135, CCI-000154, CCI-000158, CCI-000172, CCI-001464, CCI-001487, CCI-001814, CCI-001875, CCI-001876, CCI-001877, CCI-001878, CCI-001879, CCI-001880, CCI-001881, CCI-001882, CCI-001889, CCI-001914, CCI-002884, CCI-000169, CIP-004-6 R3.3, CIP-007-3 R6.5, AC-7(a), AU-7(1), AU-7(2), AU-14, AU-12(2), AU-2(a), CM-6(a), FAU_GEN.1, Req-10.1, 10.2.1, SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000475-GPOS-00220, SLES-15-030650, 4.1.1.1, SV-234964r877036_rule Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_audit
class install_audit {
package { 'audit':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "audit"
version = "*"
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure audit is installed
package:
name: audit
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85612-0
- DISA-STIG-SLES-15-030650
- NIST-800-53-AC-7(a)
- NIST-800-53-AU-12(2)
- NIST-800-53-AU-14
- NIST-800-53-AU-2(a)
- NIST-800-53-AU-7(1)
- NIST-800-53-AU-7(2)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.1
- PCI-DSSv4-10.2.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_audit_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "audit"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable auditd Service
[ref]ruleThe auditd service is an essential userspace component of
the Linux Auditing System, as it is responsible for writing audit records to
disk.
The auditd service can be enabled with the following command:
$ sudo systemctl enable auditd.service Rationale:Without establishing what type of events occurred, it would be difficult
to establish, correlate, and investigate the events leading up to an outage or attack.
Ensuring the auditd service is active ensures audit records
generated by the kernel are appropriately recorded.
Additionally, a properly configured audit subsystem ensures that actions of
individual system users can be uniquely traced to those users so they
can be held accountable for their actions. Identifiers:
CCE-85581-7 References:
BP28(R33), BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, 3.3.2, 3.3.6, CCI-000126, CCI-000130, CCI-000131, CCI-000132, CCI-000133, CCI-000134, CCI-000135, CCI-000154, CCI-000158, CCI-000172, CCI-000366, CCI-001464, CCI-001487, CCI-001814, CCI-001875, CCI-001876, CCI-001877, CCI-002884, CCI-001878, CCI-001879, CCI-001880, CCI-001881, CCI-001882, CCI-001889, CCI-001914, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, CIP-004-6 R3.3, CIP-007-3 R6.5, AC-2(g), AU-3, AU-10, AU-2(d), AU-12(c), AU-14(1), AC-6(9), CM-6(a), SI-4(23), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1, Req-10.1, 10.2.1, SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000475-GPOS-00220, SRG-APP-000095-CTR-000170, SRG-APP-000409-CTR-000990, SRG-APP-000508-CTR-001300, SRG-APP-000510-CTR-001310, SLES-15-030050, 4.1.1.2, SV-234904r854221_rule Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include enable_auditd
class enable_auditd {
service {'auditd':
enable => true,
ensure => 'running',
}
}
Remediation script: (show)
[customizations.services]
enabled = ["auditd"]
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85581-7
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030050
- NIST-800-171-3.3.1
- NIST-800-171-3.3.2
- NIST-800-171-3.3.6
- NIST-800-53-AC-2(g)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-10
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-14(1)
- NIST-800-53-AU-2(d)
- NIST-800-53-AU-3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-4(23)
- PCI-DSS-Req-10.1
- PCI-DSSv4-10.2.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_auditd_enabled
- name: Enable service auditd
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service auditd
systemd:
name: auditd
enabled: 'yes'
state: started
masked: 'no'
when:
- '"audit" in ansible_facts.packages'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"audit" in ansible_facts.packages'
tags:
- CCE-85581-7
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030050
- NIST-800-171-3.3.1
- NIST-800-171-3.3.2
- NIST-800-171-3.3.6
- NIST-800-53-AC-2(g)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-10
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-14(1)
- NIST-800-53-AU-2(d)
- NIST-800-53-AU-3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-4(23)
- PCI-DSS-Req-10.1
- PCI-DSSv4-10.2.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_auditd_enabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q audit; }; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'auditd.service'
"$SYSTEMCTL_EXEC" start 'auditd.service'
"$SYSTEMCTL_EXEC" enable 'auditd.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable Auditing for Processes Which Start Prior to the Audit Daemon
[ref]ruleTo ensure all processes can be audited, even those which start
prior to the audit daemon, add the argument audit=1 to the default
GRUB 2 command line for the Linux operating system.
Configure the default Grub2 kernel command line to contain audit=1 as follows:
# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) audit=1" Rationale:Each process on the system carries an "auditable" flag which indicates whether
its activities can be audited. Although auditd takes care of enabling
this for all processes which launch after it does, adding the kernel argument
ensures it is set for every process during boot. Identifiers:
CCE-85832-4 References:
1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.02, DSS05.03, DSS05.04, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, CCI-001464, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AC-17(1), AU-14(1), AU-10, CM-6(a), IR-5(1), DE.AE-3, DE.AE-5, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1, Req-10.3, 10.7.3, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218, SRG-OS-000254-GPOS-00095, 4.1.1.3 Remediation script: (show)
[customizations.kernel]
append = "audit=1"
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85832-4
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-17(1)
- NIST-800-53-AU-10
- NIST-800-53-AU-14(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-IR-5(1)
- PCI-DSS-Req-10.3
- PCI-DSSv4-10.7.3
- grub2_audit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Check audit argument exists
command: grep '^\s*GRUB_CMDLINE_LINUX=.*audit=' /etc/default/grub
failed_when: false
register: argcheck
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
tags:
- CCE-85832-4
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-17(1)
- NIST-800-53-AU-10
- NIST-800-53-AU-14(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-IR-5(1)
- PCI-DSS-Req-10.3
- PCI-DSSv4-10.7.3
- grub2_audit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Check audit argument exists
command: grep '^\s*GRUB_CMDLINE_LINUX=' /etc/default/grub
failed_when: false
register: linecheck
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
tags:
- CCE-85832-4
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-17(1)
- NIST-800-53-AU-10
- NIST-800-53-AU-14(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-IR-5(1)
- PCI-DSS-Req-10.3
- PCI-DSSv4-10.7.3
- grub2_audit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Add watch rule for in /etc/audit/audit.rules
ansible.builtin.lineinfile:
line: GRUB_CMDLINE_LINUX="audit=1 "
state: present
dest: /etc/default/grub
create: true
mode: '0644'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
- argcheck.rc != 0 and linecheck.rc != 0
tags:
- CCE-85832-4
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-17(1)
- NIST-800-53-AU-10
- NIST-800-53-AU-14(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-IR-5(1)
- PCI-DSS-Req-10.3
- PCI-DSSv4-10.7.3
- grub2_audit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Replace existing audit argument
replace:
path: /etc/default/grub
regexp: audit=\w+
replace: audit=1
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
- argcheck.rc == 0 and linecheck.rc == 0
tags:
- CCE-85832-4
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-17(1)
- NIST-800-53-AU-10
- NIST-800-53-AU-14(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-IR-5(1)
- PCI-DSS-Req-10.3
- PCI-DSSv4-10.7.3
- grub2_audit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Add audit argument
replace:
path: /etc/default/grub
regexp: (^\s*GRUB_CMDLINE_LINUX=.*)"
replace: \1 audit=1"
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
- argcheck.rc != 0 and linecheck.rc == 0
tags:
- CCE-85832-4
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-17(1)
- NIST-800-53-AU-10
- NIST-800-53-AU-14(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-IR-5(1)
- PCI-DSS-Req-10.3
- PCI-DSSv4-10.7.3
- grub2_audit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Update grub defaults and the bootloader menu
command: /usr/sbin/grub2-mkconfig -o /boot/grub2/grub.cfg
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
tags:
- CCE-85832-4
- CJIS-5.4.1.1
- NIST-800-171-3.3.1
- NIST-800-53-AC-17(1)
- NIST-800-53-AU-10
- NIST-800-53-AU-14(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-IR-5(1)
- PCI-DSS-Req-10.3
- PCI-DSSv4-10.7.3
- grub2_audit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2; }; then
# Correct the form of default kernel command line in GRUB
if grep -q '^\s*GRUB_CMDLINE_LINUX=.*audit=.*"' '/etc/default/grub' ; then
# modify the GRUB command-line if an audit= arg already exists
sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)audit=[^[:space:]]\+\(.*\"\)/\1audit=1\2/" '/etc/default/grub'
# Add to already existing GRUB_CMDLINE_LINUX parameters
elif grep -q '^\s*GRUB_CMDLINE_LINUX=' '/etc/default/grub' ; then
# no audit=arg is present, append it
sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)\"/\1 audit=1\"/" '/etc/default/grub'
# Add GRUB_CMDLINE_LINUX parameters line
else
echo "GRUB_CMDLINE_LINUX=\"audit=1\"" >> '/etc/default/grub'
fi
grub2-mkconfig -o /boot/grub2/grub2.cfg
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Extend Audit Backlog Limit for the Audit Daemon
[ref]ruleTo improve the kernel capacity to queue all log events, even those which occurred
prior to the audit daemon, add the argument audit_backlog_limit=8192 to the default
GRUB 2 command line for the Linux operating system.
Configure the default Grub2 kernel command line to contain audit_backlog_limit=8192 as follows:
# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) audit_backlog_limit=8192" Rationale:audit_backlog_limit sets the queue length for audit events awaiting transfer
to the audit daemon. Until the audit daemon is up and running, all log messages
are stored in this queue. If the queue is overrun during boot process, the action
defined by audit failure flag is taken. Identifiers:
CCE-91374-9 References:
CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001849, CCI-002884, CM-6(a), FAU_STG.1, FAU_STG.3, 10.7.2, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000254-GPOS-00095, SRG-OS-000341-GPOS-00132, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, 4.1.2.4 Remediation script: (show)
[customizations.kernel]
append = "audit_backlog_limit=8192"
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-91374-9
- NIST-800-53-CM-6(a)
- PCI-DSSv4-10.7.2
- grub2_audit_backlog_limit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Check audit_backlog_limit argument exists
command: grep '^\s*GRUB_CMDLINE_LINUX=.*audit_backlog_limit=' /etc/default/grub
failed_when: false
register: argcheck
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
tags:
- CCE-91374-9
- NIST-800-53-CM-6(a)
- PCI-DSSv4-10.7.2
- grub2_audit_backlog_limit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Check audit_backlog_limit argument exists
command: grep '^\s*GRUB_CMDLINE_LINUX=' /etc/default/grub
failed_when: false
register: linecheck
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
tags:
- CCE-91374-9
- NIST-800-53-CM-6(a)
- PCI-DSSv4-10.7.2
- grub2_audit_backlog_limit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Add watch rule for in /etc/audit/audit.rules
ansible.builtin.lineinfile:
line: GRUB_CMDLINE_LINUX="audit_backlog_limit=8192 "
state: present
dest: /etc/default/grub
create: true
mode: '0644'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
- argcheck.rc != 0 and linecheck.rc != 0
tags:
- CCE-91374-9
- NIST-800-53-CM-6(a)
- PCI-DSSv4-10.7.2
- grub2_audit_backlog_limit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Replace existing audit_backlog_limit argument
replace:
path: /etc/default/grub
regexp: audit_backlog_limit=\w+
replace: audit_backlog_limit=8192
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
- argcheck.rc == 0 and linecheck.rc == 0
tags:
- CCE-91374-9
- NIST-800-53-CM-6(a)
- PCI-DSSv4-10.7.2
- grub2_audit_backlog_limit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Add audit_backlog_limit argument
replace:
path: /etc/default/grub
regexp: (^\s*GRUB_CMDLINE_LINUX=.*)"
replace: \1 audit_backlog_limit=8192"
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
- argcheck.rc != 0 and linecheck.rc == 0
tags:
- CCE-91374-9
- NIST-800-53-CM-6(a)
- PCI-DSSv4-10.7.2
- grub2_audit_backlog_limit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
- name: Update grub defaults and the bootloader menu
command: /usr/sbin/grub2-mkconfig -o /boot/grub2/grub.cfg
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
tags:
- CCE-91374-9
- NIST-800-53-CM-6(a)
- PCI-DSSv4-10.7.2
- grub2_audit_backlog_limit_argument
- low_disruption
- low_severity
- medium_complexity
- reboot_required
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2; }; then
# Correct the form of default kernel command line in GRUB
if grep -q '^\s*GRUB_CMDLINE_LINUX=.*audit_backlog_limit=.*"' '/etc/default/grub' ; then
# modify the GRUB command-line if an audit_backlog_limit= arg already exists
sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)audit_backlog_limit=[^[:space:]]\+\(.*\"\)/\1audit_backlog_limit=8192\2/" '/etc/default/grub'
# Add to already existing GRUB_CMDLINE_LINUX parameters
elif grep -q '^\s*GRUB_CMDLINE_LINUX=' '/etc/default/grub' ; then
# no audit_backlog_limit=arg is present, append it
sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)\"/\1 audit_backlog_limit=8192\"/" '/etc/default/grub'
# Add GRUB_CMDLINE_LINUX parameters line
else
echo "GRUB_CMDLINE_LINUX=\"audit_backlog_limit=8192\"" >> '/etc/default/grub'
fi
grub2-mkconfig -o /boot/grub2/grub2.cfg
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
GRUB2 bootloader configuration
[ref]groupDuring the boot process, the boot loader is
responsible for starting the execution of the kernel and passing
options to it. The boot loader allows for the selection of
different kernels - possibly on different partitions or media.
The default SUSE Linux Enterprise 15 boot loader for x86 systems is called GRUB2.
Options it can pass to the kernel include single-user mode, which
provides root access without any authentication, and the ability to
disable SELinux. To prevent local users from modifying the boot
parameters and endangering security, protect the boot loader configuration
with a password and ensure its configuration file's permissions
are set properly. |
contains 3 rules |
Non-UEFI GRUB2 bootloader configuration
[ref]groupNon-UEFI GRUB2 bootloader configuration |
contains 3 rules |
Verify /boot/grub2/grub.cfg Group Ownership
[ref]ruleThe file /boot/grub2/grub.cfg should
be group-owned by the root group to prevent
destruction or modification of the file.
To properly set the group owner of /boot/grub2/grub.cfg , run the command:
$ sudo chgrp root /boot/grub2/grub.cfg Rationale:The root group is a highly-privileged group. Furthermore, the group-owner of this
file should not have any access privileges anyway. Identifiers:
CCE-85849-8 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-7.1, 2.2.6, SRG-OS-000480-GPOS-00227, 1.5.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85849-8
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Test for existence /boot/grub2/grub.cfg
stat:
path: /boot/grub2/grub.cfg
register: file_exists
when:
- '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
- '"grub2" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85849-8
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /boot/grub2/grub.cfg
file:
path: /boot/grub2/grub.cfg
group: '0'
when:
- '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
- '"grub2" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85849-8
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -d /sys/firmware/efi ] && rpm --quiet -q grub2 && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
chgrp 0 /boot/grub2/grub.cfg
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify /boot/grub2/grub.cfg User Ownership
[ref]ruleThe file /boot/grub2/grub.cfg should
be owned by the root user to prevent destruction
or modification of the file.
To properly set the owner of /boot/grub2/grub.cfg , run the command:
$ sudo chown root /boot/grub2/grub.cfg Rationale:Only root should be able to modify important boot parameters. Identifiers:
CCE-85848-0 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-7.1, 2.2.6, SRG-OS-000480-GPOS-00227, 1.5.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85848-0
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Test for existence /boot/grub2/grub.cfg
stat:
path: /boot/grub2/grub.cfg
register: file_exists
when:
- '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
- '"grub2" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85848-0
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /boot/grub2/grub.cfg
file:
path: /boot/grub2/grub.cfg
owner: '0'
when:
- '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
- '"grub2" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85848-0
- CJIS-5.5.2.2
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-7.1
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -d /sys/firmware/efi ] && rpm --quiet -q grub2 && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
chown 0 /boot/grub2/grub.cfg
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify /boot/grub2/grub.cfg Permissions
[ref]ruleFile permissions for /boot/grub2/grub.cfg should be set to 600.
To properly set the permissions of /boot/grub2/grub.cfg , run the command:
$ sudo chmod 600 /boot/grub2/grub.cfg Rationale:Proper permissions ensure that only the root user can modify important boot
parameters. Identifiers:
CCE-91426-7 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, 1.5.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-91426-7
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Test for existence /boot/grub2/grub.cfg
stat:
path: /boot/grub2/grub.cfg
register: file_exists
when:
- '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
- '"grub2" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91426-7
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xwrs,o-xwrt on /boot/grub2/grub.cfg
file:
path: /boot/grub2/grub.cfg
mode: u-xs,g-xwrs,o-xwrt
when:
- '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
- '"grub2" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91426-7
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_grub2_cfg
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -d /sys/firmware/efi ] && rpm --quiet -q grub2 && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
chmod u-xs,g-xwrs,o-xwrt /boot/grub2/grub.cfg
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Configure Syslog
[ref]groupThe syslog service has been the default Unix logging mechanism for
many years. It has a number of downsides, including inconsistent log format,
lack of authentication for received messages, and lack of authentication,
encryption, or reliable transport for messages sent over a network. However,
due to its long history, syslog is a de facto standard which is supported by
almost all Unix applications.
In SUSE Linux Enterprise 15, rsyslog has replaced ksyslogd as the
syslog daemon of choice, and it includes some additional security features
such as reliable, connection-oriented (i.e. TCP) transmission of logs, the
option to log to database formats, and the encryption of log data en route to
a central logging server.
This section discusses how to configure rsyslog for
best effect, and how to use tools provided with the system to maintain and
monitor logs. |
contains 5 rules |
Ensure Proper Configuration of Log Files
[ref]groupThe file /etc/rsyslog.conf controls where log message are written.
These are controlled by lines called rules, which consist of a
selector and an action.
These rules are often customized depending on the role of the system, the
requirements of the environment, and whatever may enable
the administrator to most effectively make use of log data.
The default rules in SUSE Linux Enterprise 15 are:
*.info;mail.none;authpriv.none;cron.none /var/log/messages
authpriv.* /var/log/secure
mail.* -/var/log/maillog
cron.* /var/log/cron
*.emerg *
uucp,news.crit /var/log/spooler
local7.* /var/log/boot.log
See the man page rsyslog.conf(5) for more information.
Note that the rsyslog daemon can be configured to use a timestamp format that
some log processing programs may not understand. If this occurs,
edit the file /etc/rsyslog.conf and add or edit the following line:
$ ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat |
contains 3 rules |
Ensure Log Files Are Owned By Appropriate Group
[ref]ruleThe group-owner of all log files written by
rsyslog should be root .
These log files are determined by the second part of each Rule line in
/etc/rsyslog.conf and typically all appear in /var/log .
For each log file LOGFILE referenced in /etc/rsyslog.conf ,
run the following command to inspect the file's group owner:
$ ls -l LOGFILE
If the owner is not root ,
run the following command to
correct this:
$ sudo chgrp root LOGFILE Rationale:The log files generated by rsyslog contain valuable information regarding system
configuration, user authentication, and other such information. Log files should be
protected from unauthorized access. Identifiers:
CCE-85838-1 References:
BP28(R46), BP28(R5), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001314, 4.3.3.7.3, SR 2.1, SR 5.2, 0988, 1405, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-10.5.1, Req-10.5.2, 10.3.2, 4.2.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure Log Files Are Owned By Appropriate Group - Set rsyslog logfile configuration
facts
ansible.builtin.set_fact:
rsyslog_etc_config: /etc/rsyslog.conf
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85838-1
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_groupownership
- name: Ensure Log Files Are Owned By Appropriate Group - Get IncludeConfig directive
ansible.builtin.shell: |
set -o pipefail
grep -e '$IncludeConfig' {{ rsyslog_etc_config }} | cut -d ' ' -f 2 || true
register: rsyslog_old_inc
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85838-1
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_groupownership
- name: Ensure Log Files Are Owned By Appropriate Group - Get include files directives
ansible.builtin.shell: |
set -o pipefail
awk '/)/{f=0} /include\(/{f=1} f{nf=gensub("^(include\\(|\\s*)file=\"(\\S+)\".*","\\2",1); if($0!=nf){print nf}}' {{ rsyslog_etc_config }} || true
register: rsyslog_new_inc
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85838-1
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_groupownership
- name: Ensure Log Files Are Owned By Appropriate Group - Aggregate rsyslog includes
ansible.builtin.set_fact:
include_config_output: '{{ rsyslog_old_inc.stdout_lines + rsyslog_new_inc.stdout_lines
}}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85838-1
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_groupownership
- name: Ensure Log Files Are Owned By Appropriate Group - List all config files
ansible.builtin.find:
paths: '{{ item | dirname }}'
patterns: '{{ item | basename }}'
hidden: false
follow: true
loop: '{{ include_config_output | list + [rsyslog_etc_config] }}'
register: rsyslog_config_files
failed_when: false
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85838-1
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_groupownership
- name: Ensure Log Files Are Owned By Appropriate Group - Extract log files old format
ansible.builtin.shell: |
set -o pipefail
grep -oP '^[^(\s|#|\$)]+[\s]+.*[\s]+-?(/+[^:;\s]+);*\.*$' {{ item.1.path }} | \
awk '{print $NF}' | \
sed -e 's/^-//' || true
loop: '{{ rsyslog_config_files.results | subelements(''files'') }}'
register: log_files_old
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85838-1
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_groupownership
- name: Ensure Log Files Are Owned By Appropriate Group - Extract log files new format
ansible.builtin.shell: |
set -o pipefail
grep -ozP "action\s*\(\s*type\s*=\s*\"omfile\"[^\)]*\)" {{ item.1.path }} | \
grep -aoP "File\s*=\s*\"([/[:alnum:][:punct:]]*)\"\s*\)" | \
grep -oE "\"([/[:alnum:][:punct:]]*)\"" | \
tr -d "\""|| true
loop: '{{ rsyslog_config_files.results | subelements(''files'') }}'
register: log_files_new
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85838-1
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_groupownership
- name: Ensure Log Files Are Owned By Appropriate Group - Sum all log files found
ansible.builtin.set_fact:
log_files: '{{ log_files_new.results | map(attribute=''stdout_lines'') | list
| flatten | unique + log_files_old.results | map(attribute=''stdout_lines'')
| list | flatten | unique }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85838-1
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_groupownership
- name: Ensure Log Files Are Owned By Appropriate Group -Setup log files attribute
ansible.builtin.file:
path: '{{ item }}'
group: root
state: file
loop: '{{ log_files | list | flatten | unique }}'
failed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85838-1
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_groupownership
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# List of log file paths to be inspected for correct permissions
# * Primarily inspect log file paths listed in /etc/rsyslog.conf
RSYSLOG_ETC_CONFIG="/etc/rsyslog.conf"
# * And also the log file paths listed after rsyslog's $IncludeConfig directive
# (store the result into array for the case there's shell glob used as value of IncludeConfig)
readarray -t OLD_INC < <(grep -e "\$IncludeConfig[[:space:]]\+[^[:space:];]\+" /etc/rsyslog.conf | cut -d ' ' -f 2)
readarray -t RSYSLOG_INCLUDE_CONFIG < <(for INCPATH in "${OLD_INC[@]}"; do eval printf '%s\\n' "${INCPATH}"; done)
readarray -t NEW_INC < <(sed -n '/^\s*include(/,/)/Ip' /etc/rsyslog.conf | sed -n 's@.*file\s*=\s*"\([/[:alnum:][:punct:]]*\)".*@\1@Ip')
readarray -t RSYSLOG_INCLUDE < <(for INCPATH in "${NEW_INC[@]}"; do eval printf '%s\\n' "${INCPATH}"; done)
# Declare an array to hold the final list of different log file paths
declare -a LOG_FILE_PATHS
# Array to hold all rsyslog config entries
RSYSLOG_CONFIGS=()
RSYSLOG_CONFIGS=("${RSYSLOG_ETC_CONFIG}" "${RSYSLOG_INCLUDE_CONFIG[@]}" "${RSYSLOG_INCLUDE[@]}")
# Get full list of files to be checked
# RSYSLOG_CONFIGS may contain globs such as
# /etc/rsyslog.d/*.conf /etc/rsyslog.d/*.frule
# So, loop over the entries in RSYSLOG_CONFIGS and use find to get the list of included files.
RSYSLOG_CONFIG_FILES=()
for ENTRY in "${RSYSLOG_CONFIGS[@]}"
do
# If directory, rsyslog will search for config files in recursively.
# However, files in hidden sub-directories or hidden files will be ignored.
if [ -d "${ENTRY}" ]
then
readarray -t FINDOUT < <(find "${ENTRY}" -not -path '*/.*' -type f)
RSYSLOG_CONFIG_FILES+=("${FINDOUT[@]}")
elif [ -f "${ENTRY}" ]
then
RSYSLOG_CONFIG_FILES+=("${ENTRY}")
else
echo "Invalid include object: ${ENTRY}"
fi
done
# Browse each file selected above as containing paths of log files
# ('/etc/rsyslog.conf' and '/etc/rsyslog.d/*.conf' in the default configuration)
for LOG_FILE in "${RSYSLOG_CONFIG_FILES[@]}"
do
# From each of these files extract just particular log file path(s), thus:
# * Ignore lines starting with space (' '), comment ('#"), or variable syntax ('$') characters,
# * Ignore empty lines,
# * Strip quotes and closing brackets from paths.
# * Ignore paths that match /dev|/etc.*\.conf, as those are paths, but likely not log files
# * From the remaining valid rows select only fields constituting a log file path
# Text file column is understood to represent a log file path if and only if all of the
# following are met:
# * it contains at least one slash '/' character,
# * it is preceded by space
# * it doesn't contain space (' '), colon (':'), and semicolon (';') characters
# Search log file for path(s) only in case it exists!
if [[ -f "${LOG_FILE}" ]]
then
NORMALIZED_CONFIG_FILE_LINES=$(sed -e "/^[#|$]/d" "${LOG_FILE}")
LINES_WITH_PATHS=$(grep '[^/]*\s\+\S*/\S\+$' <<< "${NORMALIZED_CONFIG_FILE_LINES}")
FILTERED_PATHS=$(awk '{if(NF>=2&&($NF~/^\//||$NF~/^-\//)){sub(/^-\//,"/",$NF);print $NF}}' <<< "${LINES_WITH_PATHS}")
CLEANED_PATHS=$(sed -e "s/[\"')]//g; /\\/etc.*\.conf/d; /\\/dev\\//d" <<< "${FILTERED_PATHS}")
MATCHED_ITEMS=$(sed -e "/^$/d" <<< "${CLEANED_PATHS}")
# Since above sed command might return more than one item (delimited by newline), split
# the particular matches entries into new array specific for this log file
readarray -t ARRAY_FOR_LOG_FILE <<< "$MATCHED_ITEMS"
# Concatenate the two arrays - previous content of $LOG_FILE_PATHS array with
# items from newly created array for this log file
LOG_FILE_PATHS+=("${ARRAY_FOR_LOG_FILE[@]}")
# Delete the temporary array
unset ARRAY_FOR_LOG_FILE
fi
done
# Check for RainerScript action log format which might be also multiline so grep regex is a bit
# curly:
# extract possibly multiline action omfile expressions
# extract File="logfile" expression
# match only "logfile" expression
for LOG_FILE in "${RSYSLOG_CONFIG_FILES[@]}"
do
ACTION_OMFILE_LINES=$(grep -iozP "action\s*\(\s*type\s*=\s*\"omfile\"[^\)]*\)" "${LOG_FILE}")
OMFILE_LINES=$(echo "${ACTION_OMFILE_LINES}"| grep -iaoP "File\s*=\s*\"([/[:alnum:][:punct:]]*)\"\s*\)")
LOG_FILE_PATHS+=("$(echo "${OMFILE_LINES}"| grep -oE "\"([/[:alnum:][:punct:]]*)\""|tr -d "\"")")
done
# Ensure the correct attribute if file exists
FILE_CMD="chgrp"
for LOG_FILE_PATH in "${LOG_FILE_PATHS[@]}"
do
# Sanity check - if particular $LOG_FILE_PATH is empty string, skip it from further processing
if [ -z "$LOG_FILE_PATH" ]
then
continue
fi
$FILE_CMD "root" "$LOG_FILE_PATH"
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure Log Files Are Owned By Appropriate User
[ref]ruleThe owner of all log files written by
rsyslog should be
root .
These log files are determined by the second part of each Rule line in
/etc/rsyslog.conf and typically all appear in /var/log .
For each log file LOGFILE referenced in /etc/rsyslog.conf ,
run the following command to inspect the file's owner:
$ ls -l LOGFILE
If the owner is not
root ,
run the following command to
correct this:
$ sudo chown root LOGFILE Rationale:The log files generated by rsyslog contain valuable information regarding system
configuration, user authentication, and other such information. Log files should be
protected from unauthorized access. Identifiers:
CCE-85839-9 References:
BP28(R46), BP28(R5), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001314, 4.3.3.7.3, SR 2.1, SR 5.2, 0988, 1405, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-10.5.1, Req-10.5.2, 10.3.2, 4.2.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure Log Files Are Owned By Appropriate User - Set rsyslog logfile configuration
facts
ansible.builtin.set_fact:
rsyslog_etc_config: /etc/rsyslog.conf
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85839-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_ownership
- name: Ensure Log Files Are Owned By Appropriate User - Get IncludeConfig directive
ansible.builtin.shell: |
set -o pipefail
grep -e '$IncludeConfig' {{ rsyslog_etc_config }} | cut -d ' ' -f 2 || true
register: rsyslog_old_inc
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85839-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_ownership
- name: Ensure Log Files Are Owned By Appropriate User - Get include files directives
ansible.builtin.shell: |
set -o pipefail
awk '/)/{f=0} /include\(/{f=1} f{nf=gensub("^(include\\(|\\s*)file=\"(\\S+)\".*","\\2",1); if($0!=nf){print nf}}' {{ rsyslog_etc_config }} || true
register: rsyslog_new_inc
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85839-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_ownership
- name: Ensure Log Files Are Owned By Appropriate User - Aggregate rsyslog includes
ansible.builtin.set_fact:
include_config_output: '{{ rsyslog_old_inc.stdout_lines + rsyslog_new_inc.stdout_lines
}}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85839-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_ownership
- name: Ensure Log Files Are Owned By Appropriate User - List all config files
ansible.builtin.find:
paths: '{{ item | dirname }}'
patterns: '{{ item | basename }}'
hidden: false
follow: true
loop: '{{ include_config_output | list + [rsyslog_etc_config] }}'
register: rsyslog_config_files
failed_when: false
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85839-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_ownership
- name: Ensure Log Files Are Owned By Appropriate User - Extract log files old format
ansible.builtin.shell: |
set -o pipefail
grep -oP '^[^(\s|#|\$)]+[\s]+.*[\s]+-?(/+[^:;\s]+);*\.*$' {{ item.1.path }} | \
awk '{print $NF}' | \
sed -e 's/^-//' || true
loop: '{{ rsyslog_config_files.results | subelements(''files'') }}'
register: log_files_old
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85839-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_ownership
- name: Ensure Log Files Are Owned By Appropriate User - Extract log files new format
ansible.builtin.shell: |
set -o pipefail
grep -ozP "action\s*\(\s*type\s*=\s*\"omfile\"[^\)]*\)" {{ item.1.path }} | \
grep -aoP "File\s*=\s*\"([/[:alnum:][:punct:]]*)\"\s*\)" | \
grep -oE "\"([/[:alnum:][:punct:]]*)\"" | \
tr -d "\""|| true
loop: '{{ rsyslog_config_files.results | subelements(''files'') }}'
register: log_files_new
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85839-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_ownership
- name: Ensure Log Files Are Owned By Appropriate User - Sum all log files found
ansible.builtin.set_fact:
log_files: '{{ log_files_new.results | map(attribute=''stdout_lines'') | list
| flatten | unique + log_files_old.results | map(attribute=''stdout_lines'')
| list | flatten | unique }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85839-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_ownership
- name: Ensure Log Files Are Owned By Appropriate User -Setup log files attribute
ansible.builtin.file:
path: '{{ item }}'
owner: root
state: file
loop: '{{ log_files | list | flatten | unique }}'
failed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85839-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.2
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_ownership
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# List of log file paths to be inspected for correct permissions
# * Primarily inspect log file paths listed in /etc/rsyslog.conf
RSYSLOG_ETC_CONFIG="/etc/rsyslog.conf"
# * And also the log file paths listed after rsyslog's $IncludeConfig directive
# (store the result into array for the case there's shell glob used as value of IncludeConfig)
readarray -t OLD_INC < <(grep -e "\$IncludeConfig[[:space:]]\+[^[:space:];]\+" /etc/rsyslog.conf | cut -d ' ' -f 2)
readarray -t RSYSLOG_INCLUDE_CONFIG < <(for INCPATH in "${OLD_INC[@]}"; do eval printf '%s\\n' "${INCPATH}"; done)
readarray -t NEW_INC < <(sed -n '/^\s*include(/,/)/Ip' /etc/rsyslog.conf | sed -n 's@.*file\s*=\s*"\([/[:alnum:][:punct:]]*\)".*@\1@Ip')
readarray -t RSYSLOG_INCLUDE < <(for INCPATH in "${NEW_INC[@]}"; do eval printf '%s\\n' "${INCPATH}"; done)
# Declare an array to hold the final list of different log file paths
declare -a LOG_FILE_PATHS
# Array to hold all rsyslog config entries
RSYSLOG_CONFIGS=()
RSYSLOG_CONFIGS=("${RSYSLOG_ETC_CONFIG}" "${RSYSLOG_INCLUDE_CONFIG[@]}" "${RSYSLOG_INCLUDE[@]}")
# Get full list of files to be checked
# RSYSLOG_CONFIGS may contain globs such as
# /etc/rsyslog.d/*.conf /etc/rsyslog.d/*.frule
# So, loop over the entries in RSYSLOG_CONFIGS and use find to get the list of included files.
RSYSLOG_CONFIG_FILES=()
for ENTRY in "${RSYSLOG_CONFIGS[@]}"
do
# If directory, rsyslog will search for config files in recursively.
# However, files in hidden sub-directories or hidden files will be ignored.
if [ -d "${ENTRY}" ]
then
readarray -t FINDOUT < <(find "${ENTRY}" -not -path '*/.*' -type f)
RSYSLOG_CONFIG_FILES+=("${FINDOUT[@]}")
elif [ -f "${ENTRY}" ]
then
RSYSLOG_CONFIG_FILES+=("${ENTRY}")
else
echo "Invalid include object: ${ENTRY}"
fi
done
# Browse each file selected above as containing paths of log files
# ('/etc/rsyslog.conf' and '/etc/rsyslog.d/*.conf' in the default configuration)
for LOG_FILE in "${RSYSLOG_CONFIG_FILES[@]}"
do
# From each of these files extract just particular log file path(s), thus:
# * Ignore lines starting with space (' '), comment ('#"), or variable syntax ('$') characters,
# * Ignore empty lines,
# * Strip quotes and closing brackets from paths.
# * Ignore paths that match /dev|/etc.*\.conf, as those are paths, but likely not log files
# * From the remaining valid rows select only fields constituting a log file path
# Text file column is understood to represent a log file path if and only if all of the
# following are met:
# * it contains at least one slash '/' character,
# * it is preceded by space
# * it doesn't contain space (' '), colon (':'), and semicolon (';') characters
# Search log file for path(s) only in case it exists!
if [[ -f "${LOG_FILE}" ]]
then
NORMALIZED_CONFIG_FILE_LINES=$(sed -e "/^[#|$]/d" "${LOG_FILE}")
LINES_WITH_PATHS=$(grep '[^/]*\s\+\S*/\S\+$' <<< "${NORMALIZED_CONFIG_FILE_LINES}")
FILTERED_PATHS=$(awk '{if(NF>=2&&($NF~/^\//||$NF~/^-\//)){sub(/^-\//,"/",$NF);print $NF}}' <<< "${LINES_WITH_PATHS}")
CLEANED_PATHS=$(sed -e "s/[\"')]//g; /\\/etc.*\.conf/d; /\\/dev\\//d" <<< "${FILTERED_PATHS}")
MATCHED_ITEMS=$(sed -e "/^$/d" <<< "${CLEANED_PATHS}")
# Since above sed command might return more than one item (delimited by newline), split
# the particular matches entries into new array specific for this log file
readarray -t ARRAY_FOR_LOG_FILE <<< "$MATCHED_ITEMS"
# Concatenate the two arrays - previous content of $LOG_FILE_PATHS array with
# items from newly created array for this log file
LOG_FILE_PATHS+=("${ARRAY_FOR_LOG_FILE[@]}")
# Delete the temporary array
unset ARRAY_FOR_LOG_FILE
fi
done
# Check for RainerScript action log format which might be also multiline so grep regex is a bit
# curly:
# extract possibly multiline action omfile expressions
# extract File="logfile" expression
# match only "logfile" expression
for LOG_FILE in "${RSYSLOG_CONFIG_FILES[@]}"
do
ACTION_OMFILE_LINES=$(grep -iozP "action\s*\(\s*type\s*=\s*\"omfile\"[^\)]*\)" "${LOG_FILE}")
OMFILE_LINES=$(echo "${ACTION_OMFILE_LINES}"| grep -iaoP "File\s*=\s*\"([/[:alnum:][:punct:]]*)\"\s*\)")
LOG_FILE_PATHS+=("$(echo "${OMFILE_LINES}"| grep -oE "\"([/[:alnum:][:punct:]]*)\""|tr -d "\"")")
done
# Ensure the correct attribute if file exists
FILE_CMD="chown"
for LOG_FILE_PATH in "${LOG_FILE_PATHS[@]}"
do
# Sanity check - if particular $LOG_FILE_PATH is empty string, skip it from further processing
if [ -z "$LOG_FILE_PATH" ]
then
continue
fi
$FILE_CMD "root" "$LOG_FILE_PATH"
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure System Log Files Have Correct Permissions
[ref]ruleThe file permissions for all log files written by rsyslog should
be set to 640, or more restrictive. These log files are determined by the
second part of each Rule line in /etc/rsyslog.conf and typically
all appear in /var/log . For each log file LOGFILE
referenced in /etc/rsyslog.conf , run the following command to
inspect the file's permissions:
$ ls -l LOGFILE
If the permissions are not 640 or more restrictive, run the following
command to correct this:
$ sudo chmod 640 LOGFILE "Rationale:Log files can contain valuable information regarding system
configuration. If the system log files are not protected unauthorized
users could change the logged data, eliminating their forensic value. Identifiers:
CCE-85837-3 References:
BP28(R36), CCI-001314, 0988, 1405, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), Req-10.5.1, Req-10.5.2, 10.3.1, 4.2.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure System Log Files Have Correct Permissions - Set rsyslog logfile configuration
facts
ansible.builtin.set_fact:
rsyslog_etc_config: /etc/rsyslog.conf
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85837-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.1
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_permissions
- name: Ensure System Log Files Have Correct Permissions - Get IncludeConfig directive
ansible.builtin.shell: |
set -o pipefail
grep -e '$IncludeConfig' {{ rsyslog_etc_config }} | cut -d ' ' -f 2 || true
register: rsyslog_old_inc
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85837-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.1
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_permissions
- name: Ensure System Log Files Have Correct Permissions - Get include files directives
ansible.builtin.shell: |
set -o pipefail
awk '/)/{f=0} /include\(/{f=1} f{nf=gensub("^(include\\(|\\s*)file=\"(\\S+)\".*","\\2",1); if($0!=nf){print nf}}' {{ rsyslog_etc_config }} || true
register: rsyslog_new_inc
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85837-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.1
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_permissions
- name: Ensure System Log Files Have Correct Permissions - Aggregate rsyslog includes
ansible.builtin.set_fact:
include_config_output: '{{ rsyslog_old_inc.stdout_lines + rsyslog_new_inc.stdout_lines
}}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85837-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.1
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_permissions
- name: Ensure System Log Files Have Correct Permissions - List all config files
ansible.builtin.find:
paths: '{{ item | dirname }}'
patterns: '{{ item | basename }}'
hidden: false
follow: true
loop: '{{ include_config_output | list + [rsyslog_etc_config] }}'
register: rsyslog_config_files
failed_when: false
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85837-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.1
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_permissions
- name: Ensure System Log Files Have Correct Permissions - Extract log files old format
ansible.builtin.shell: |
set -o pipefail
grep -oP '^[^(\s|#|\$)]+[\s]+.*[\s]+-?(/+[^:;\s]+);*\.*$' {{ item.1.path }} | \
awk '{print $NF}' | \
sed -e 's/^-//' || true
loop: '{{ rsyslog_config_files.results | subelements(''files'') }}'
register: log_files_old
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85837-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.1
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_permissions
- name: Ensure System Log Files Have Correct Permissions - Extract log files new format
ansible.builtin.shell: |
set -o pipefail
grep -ozP "action\s*\(\s*type\s*=\s*\"omfile\"[^\)]*\)" {{ item.1.path }} | \
grep -aoP "File\s*=\s*\"([/[:alnum:][:punct:]]*)\"\s*\)" | \
grep -oE "\"([/[:alnum:][:punct:]]*)\"" | \
tr -d "\""|| true
loop: '{{ rsyslog_config_files.results | subelements(''files'') }}'
register: log_files_new
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85837-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.1
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_permissions
- name: Ensure System Log Files Have Correct Permissions - Sum all log files found
ansible.builtin.set_fact:
log_files: '{{ log_files_new.results | map(attribute=''stdout_lines'') | list
| flatten | unique + log_files_old.results | map(attribute=''stdout_lines'')
| list | flatten | unique }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85837-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.1
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_permissions
- name: Ensure System Log Files Have Correct Permissions -Setup log files attribute
ansible.builtin.file:
path: '{{ item }}'
mode: '0640'
state: file
loop: '{{ log_files | list | flatten | unique }}'
failed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85837-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.5.1
- PCI-DSS-Req-10.5.2
- PCI-DSSv4-10.3.1
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- rsyslog_files_permissions
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# List of log file paths to be inspected for correct permissions
# * Primarily inspect log file paths listed in /etc/rsyslog.conf
RSYSLOG_ETC_CONFIG="/etc/rsyslog.conf"
# * And also the log file paths listed after rsyslog's $IncludeConfig directive
# (store the result into array for the case there's shell glob used as value of IncludeConfig)
readarray -t OLD_INC < <(grep -e "\$IncludeConfig[[:space:]]\+[^[:space:];]\+" /etc/rsyslog.conf | cut -d ' ' -f 2)
readarray -t RSYSLOG_INCLUDE_CONFIG < <(for INCPATH in "${OLD_INC[@]}"; do eval printf '%s\\n' "${INCPATH}"; done)
readarray -t NEW_INC < <(sed -n '/^\s*include(/,/)/Ip' /etc/rsyslog.conf | sed -n 's@.*file\s*=\s*"\([/[:alnum:][:punct:]]*\)".*@\1@Ip')
readarray -t RSYSLOG_INCLUDE < <(for INCPATH in "${NEW_INC[@]}"; do eval printf '%s\\n' "${INCPATH}"; done)
# Declare an array to hold the final list of different log file paths
declare -a LOG_FILE_PATHS
# Array to hold all rsyslog config entries
RSYSLOG_CONFIGS=()
RSYSLOG_CONFIGS=("${RSYSLOG_ETC_CONFIG}" "${RSYSLOG_INCLUDE_CONFIG[@]}" "${RSYSLOG_INCLUDE[@]}")
# Get full list of files to be checked
# RSYSLOG_CONFIGS may contain globs such as
# /etc/rsyslog.d/*.conf /etc/rsyslog.d/*.frule
# So, loop over the entries in RSYSLOG_CONFIGS and use find to get the list of included files.
RSYSLOG_CONFIG_FILES=()
for ENTRY in "${RSYSLOG_CONFIGS[@]}"
do
# If directory, rsyslog will search for config files in recursively.
# However, files in hidden sub-directories or hidden files will be ignored.
if [ -d "${ENTRY}" ]
then
readarray -t FINDOUT < <(find "${ENTRY}" -not -path '*/.*' -type f)
RSYSLOG_CONFIG_FILES+=("${FINDOUT[@]}")
elif [ -f "${ENTRY}" ]
then
RSYSLOG_CONFIG_FILES+=("${ENTRY}")
else
echo "Invalid include object: ${ENTRY}"
fi
done
# Browse each file selected above as containing paths of log files
# ('/etc/rsyslog.conf' and '/etc/rsyslog.d/*.conf' in the default configuration)
for LOG_FILE in "${RSYSLOG_CONFIG_FILES[@]}"
do
# From each of these files extract just particular log file path(s), thus:
# * Ignore lines starting with space (' '), comment ('#"), or variable syntax ('$') characters,
# * Ignore empty lines,
# * Strip quotes and closing brackets from paths.
# * Ignore paths that match /dev|/etc.*\.conf, as those are paths, but likely not log files
# * From the remaining valid rows select only fields constituting a log file path
# Text file column is understood to represent a log file path if and only if all of the
# following are met:
# * it contains at least one slash '/' character,
# * it is preceded by space
# * it doesn't contain space (' '), colon (':'), and semicolon (';') characters
# Search log file for path(s) only in case it exists!
if [[ -f "${LOG_FILE}" ]]
then
NORMALIZED_CONFIG_FILE_LINES=$(sed -e "/^[#|$]/d" "${LOG_FILE}")
LINES_WITH_PATHS=$(grep '[^/]*\s\+\S*/\S\+$' <<< "${NORMALIZED_CONFIG_FILE_LINES}")
FILTERED_PATHS=$(awk '{if(NF>=2&&($NF~/^\//||$NF~/^-\//)){sub(/^-\//,"/",$NF);print $NF}}' <<< "${LINES_WITH_PATHS}")
CLEANED_PATHS=$(sed -e "s/[\"')]//g; /\\/etc.*\.conf/d; /\\/dev\\//d" <<< "${FILTERED_PATHS}")
MATCHED_ITEMS=$(sed -e "/^$/d" <<< "${CLEANED_PATHS}")
# Since above sed command might return more than one item (delimited by newline), split
# the particular matches entries into new array specific for this log file
readarray -t ARRAY_FOR_LOG_FILE <<< "$MATCHED_ITEMS"
# Concatenate the two arrays - previous content of $LOG_FILE_PATHS array with
# items from newly created array for this log file
LOG_FILE_PATHS+=("${ARRAY_FOR_LOG_FILE[@]}")
# Delete the temporary array
unset ARRAY_FOR_LOG_FILE
fi
done
# Check for RainerScript action log format which might be also multiline so grep regex is a bit
# curly:
# extract possibly multiline action omfile expressions
# extract File="logfile" expression
# match only "logfile" expression
for LOG_FILE in "${RSYSLOG_CONFIG_FILES[@]}"
do
ACTION_OMFILE_LINES=$(grep -iozP "action\s*\(\s*type\s*=\s*\"omfile\"[^\)]*\)" "${LOG_FILE}")
OMFILE_LINES=$(echo "${ACTION_OMFILE_LINES}"| grep -iaoP "File\s*=\s*\"([/[:alnum:][:punct:]]*)\"\s*\)")
LOG_FILE_PATHS+=("$(echo "${OMFILE_LINES}"| grep -oE "\"([/[:alnum:][:punct:]]*)\""|tr -d "\"")")
done
# Ensure the correct attribute if file exists
FILE_CMD="chmod"
for LOG_FILE_PATH in "${LOG_FILE_PATHS[@]}"
do
# Sanity check - if particular $LOG_FILE_PATH is empty string, skip it from further processing
if [ -z "$LOG_FILE_PATH" ]
then
continue
fi
$FILE_CMD "0640" "$LOG_FILE_PATH"
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure All Logs are Rotated by logrotate
[ref]group
Edit the file /etc/logrotate.d/syslog . Find the first
line, which should look like this (wrapped for clarity):
/var/log/messages /var/log/secure /var/log/maillog /var/log/spooler \
/var/log/boot.log /var/log/cron {
Edit this line so that it contains a one-space-separated
listing of each log file referenced in /etc/rsyslog.conf .
All logs in use on a system must be rotated regularly, or the
log files will consume disk space over time, eventually interfering
with system operation. The file /etc/logrotate.d/syslog is the
configuration file used by the logrotate program to maintain all
log files written by syslog . By default, it rotates logs weekly and
stores four archival copies of each log. These settings can be
modified by editing /etc/logrotate.conf , but the defaults are
sufficient for purposes of this guide.
Note that logrotate is run nightly by the cron job
/etc/cron.daily/logrotate . If particularly active logs need to be
rotated more often than once a day, some other mechanism must be
used. |
contains 2 rules |
Ensure logrotate is Installed
[ref]rulelogrotate is installed by default. The logrotate package can be installed with the following command: $ sudo zypper install logrotate Rationale:The logrotate package provides the logrotate services. Identifiers:
CCE-92561-0 References:
BP28(R71), NT12(R18), 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, CCI-000366, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), PR.PT-1, Req-10.7, 10.5.1, 4.2.4 Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_logrotate
class install_logrotate {
package { 'logrotate':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "logrotate"
version = "*"
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure logrotate is installed
package:
name: logrotate
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-92561-0
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- PCI-DSSv4-10.5.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_logrotate_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "logrotate"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable logrotate Timer
[ref]rule
The logrotate timer can be enabled with the following command:
$ sudo systemctl enable logrotate.timer Rationale:Log files that are not properly rotated run the risk of growing so large
that they fill up the /var/log partition. Valuable logging information could be lost
if the /var/log partition becomes full. Identifiers:
CCE-92585-9 References:
BP28(R71), NT12(R18), 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, CCI-000366, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), PR.PT-1, Req-10.7, 10.5.1, 4.2.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-92585-9
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- PCI-DSSv4-10.5.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- timer_logrotate_enabled
- name: Enable timer logrotate
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable timer logrotate
systemd:
name: logrotate.timer
enabled: 'yes'
state: started
when:
- '"logrotate" in ansible_facts.packages'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"logrotate" in ansible_facts.packages'
tags:
- CCE-92585-9
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- PCI-DSSv4-10.5.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- timer_logrotate_enabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q logrotate; }; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" start 'logrotate.timer'
"$SYSTEMCTL_EXEC" enable 'logrotate.timer'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Network Configuration and Firewalls
[ref]groupMost systems must be connected to a network of some
sort, and this brings with it the substantial risk of network
attack. This section discusses the security impact of decisions
about networking which must be made when configuring a system.
This section also discusses firewalls, network access
controls, and other network security frameworks, which allow
system-level rules to be written that can limit an attackers' ability
to connect to your system. These rules can specify that network
traffic should be allowed or denied from certain IP addresses,
hosts, and networks. The rules can also specify which of the
system's network services are available to particular hosts or
networks. |
contains 23 rules |
firewalld
[ref]groupThe dynamic firewall daemon firewalld provides a
dynamically managed firewall with support for network “zones” to assign
a level of trust to a network and its associated connections and interfaces.
It has support for IPv4 and IPv6 firewall settings. It supports Ethernet
bridges and has a separation of runtime and permanent configuration options.
It also has an interface for services or applications to add firewall rules
directly.
A graphical configuration tool, firewall-config , is used to configure
firewalld , which in turn uses iptables tool to communicate
with Netfilter in the kernel which implements packet filtering.
The firewall service provided by firewalld is dynamic rather than
static because changes to the configuration can be made at anytime and are
immediately implemented. There is no need to save or apply the changes. No
unintended disruption of existing network connections occurs as no part of
the firewall has to be reloaded. |
contains 3 rules |
Inspect and Activate Default firewalld Rules
[ref]groupFirewalls can be used to separate networks into different zones
based on the level of trust the user has decided to place on the devices and
traffic within that network. NetworkManager informs firewalld to which
zone an interface belongs. An interface's assigned zone can be changed by
NetworkManager or via the firewall-config tool.
The zone settings in /etc/firewalld/ are a range of preset settings
which can be quickly applied to a network interface. These are the zones
provided by firewalld sorted according to the default trust level of the
zones from untrusted to trusted:
drop
Any incoming network packets are dropped, there is no
reply. Only outgoing network connections are possible. block
Any incoming network connections are rejected with an
icmp-host-prohibited message for IPv4 and icmp6-adm-prohibited
for IPv6. Only network connections initiated from within the system are
possible. public
For use in public areas. You do not trust the other
computers on the network to not harm your computer. Only selected incoming
connections are accepted. external
For use on external networks with masquerading enabled
especially for routers. You do not trust the other computers on the network to
not harm your computer. Only selected incoming connections are accepted. dmz
For computers in your demilitarized zone that are
publicly-accessible with limited access to your internal network. Only selected
incoming connections are accepted. work
For use in work areas. You mostly trust the other computers
on networks to not harm your computer. Only selected incoming connections are
accepted. home
For use in home areas. You mostly trust the other computers
on networks to not harm your computer. Only selected incoming connections are
accepted. internal
For use on internal networks. You mostly trust the
other computers on the networks to not harm your computer. Only selected
incoming connections are accepted. trusted
All network connections are accepted.
It is possible to designate one of these zones to be the default zone. When
interface connections are added to NetworkManager , they are assigned
to the default zone. On installation, the default zone in firewalld is set to
be the public zone.
To find out all the settings of a zone, for example the public zone,
enter the following command as root:
# firewall-cmd --zone=public --list-all
Example output of this command might look like the following:
# firewall-cmd --zone=public --list-all
public
interfaces:
services: mdns dhcpv6-client ssh
ports:
forward-ports:
icmp-blocks: source-quench
To view the network zones currently active, enter the following command as root:
# firewall-cmd --get-service
The following listing displays the result of this command
on common SUSE Linux Enterprise 15 system:
# firewall-cmd --get-service
amanda-client bacula bacula-client dhcp dhcpv6 dhcpv6-client dns ftp
high-availability http https imaps ipp ipp-client ipsec kerberos kpasswd
ldap ldaps libvirt libvirt-tls mdns mountd ms-wbt mysql nfs ntp openvpn
pmcd pmproxy pmwebapi pmwebapis pop3s postgresql proxy-dhcp radius rpc-bind
samba samba-client smtp ssh telnet tftp tftp-client transmission-client
vnc-server wbem-https
Finally to view the network zones that will be active after the next firewalld
service reload, enter the following command as root:
# firewall-cmd --get-service --permanent |
contains 1 rule |
Verify firewalld Enabled
[ref]rule
The firewalld service can be enabled with the following command:
$ sudo systemctl enable firewalld.service Rationale:Access control methods provide the ability to enhance system security posture
by restricting services and known good IP addresses and address ranges. This
prevents connections from unknown hosts and protocols. Identifiers:
CCE-85751-6 References:
11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.3, 3.4.7, CCI-000366, CCI-000382, CCI-002314, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CIP-003-8 R4, CIP-003-8 R5, CIP-004-6 R3, CM-7, CM-7.1(iii), CM-7(b), AC-17(1), PR.IP-1, FMT_SMF_EXT.1, 1.2.1, SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115, SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00231, SRG-OS-000480-GPOS-00232, SLES-15-010220, 3.5.1.3, SV-234821r854186_rule Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include enable_firewalld
class enable_firewalld {
service {'firewalld':
enable => true,
ensure => 'running',
}
}
Remediation script: (show)
[customizations.services]
enabled = ["firewalld"]
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85751-6
- DISA-STIG-SLES-15-010220
- NIST-800-171-3.1.3
- NIST-800-171-3.4.7
- NIST-800-53-AC-17(1)
- NIST-800-53-CM-7
- NIST-800-53-CM-7(b)
- NIST-800-53-CM-7.1(iii)
- PCI-DSSv4-1.2.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_firewalld_enabled
- name: Enable service firewalld
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service firewalld
systemd:
name: firewalld
enabled: 'yes'
state: started
masked: 'no'
when:
- '"firewalld" in ansible_facts.packages'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"firewalld" in ansible_facts.packages'
tags:
- CCE-85751-6
- DISA-STIG-SLES-15-010220
- NIST-800-171-3.1.3
- NIST-800-171-3.4.7
- NIST-800-53-AC-17(1)
- NIST-800-53-CM-7
- NIST-800-53-CM-7(b)
- NIST-800-53-CM-7.1(iii)
- PCI-DSSv4-1.2.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_firewalld_enabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q firewalld; }; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'firewalld.service'
"$SYSTEMCTL_EXEC" start 'firewalld.service'
"$SYSTEMCTL_EXEC" enable 'firewalld.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Strengthen the Default Ruleset
[ref]groupThe default rules can be strengthened. The system
scripts that activate the firewall rules expect them to be defined
in configuration files under the /etc/firewalld/services
and /etc/firewalld/zones directories.
The following recommendations describe how to strengthen the
default ruleset configuration file. An alternative to editing this
configuration file is to create a shell script that makes calls to
the firewall-cmd program to load in rules under the /etc/firewalld/services
and /etc/firewalld/zones directories.
Instructions apply to both unless otherwise noted. Language and address
conventions for regular firewalld rules are used throughout this section. Warning:
The program firewall-config
allows additional services to penetrate the default firewall rules
and automatically adjusts the firewalld ruleset(s). |
contains 2 rules |
Ensure firewall rules exist for all open ports
[ref]ruleAny ports that have been opened on non-loopback addresses need firewall rules to govern
traffic. Warning:
To prevent denying any access to the system, automatic remediation
of this control is not available. Remediation must be automated as
a component of machine provisioning, or followed manually as outlined
above. Rationale:Without a firewall rule configured for open ports default firewall policy will drop all
packets to these ports. |
Set Default firewalld Zone for Incoming Packets
[ref]ruleTo set the default zone to drop for
the built-in default zone which processes incoming IPv4 and IPv6 packets,
modify the following line in
/etc/firewalld/firewalld.conf to be:
DefaultZone=drop Warning:
To prevent denying any access to the system, automatic remediation
of this control is not available. Remediation must be automated as
a component of machine provisioning, or followed manually as outlined
above. Rationale:In firewalld the default zone is applied only after all
the applicable rules in the table are examined for a match. Setting the
default zone to drop implements proper design for a firewall, i.e.
any packets which are not explicitly permitted should not be
accepted. Identifiers:
CCE-91410-1 References:
11, 14, 3, 9, 5.10.1, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.3, 3.4.7, 3.13.6, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, 1416, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CA-3(5), CM-7(b), SC-7(23), CM-6(a), PR.IP-1, PR.PT-3, FMT_MOF_EXT.1, Req-1.4, 1.3.1, 1.5.1, SRG-OS-000480-GPOS-00227, 3.5.1.4 |
iptables and ip6tables
[ref]groupA host-based firewall called netfilter is included as
part of the Linux kernel distributed with the system. It is
activated by default. This firewall is controlled by the program
iptables , and the entire capability is frequently referred to by
this name. An analogous program called ip6tables handles filtering
for IPv6.
Unlike TCP Wrappers, which depends on the network server
program to support and respect the rules written, netfilter
filtering occurs at the kernel level, before a program can even
process the data from the network packet. As such, any program on
the system is affected by the rules written.
This section provides basic information about strengthening
the iptables and ip6tables configurations included with the system.
For more complete information that may allow the construction of a
sophisticated ruleset tailored to your environment, please consult
the references at the end of this section. |
contains 3 rules |
Inspect and Activate Default Rules
[ref]groupView the currently-enforced iptables rules by running
the command:
$ sudo iptables -nL --line-numbers
The command is analogous for ip6tables .
If the firewall does not appear to be active (i.e., no rules
appear), activate it and ensure that it starts at boot by issuing
the following commands (and analogously for ip6tables ):
$ sudo service iptables restart
The default iptables rules are:
Chain INPUT (policy ACCEPT)
num target prot opt source destination
1 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
2 ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0
3 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
4 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
5 REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT)
num target prot opt source destination
1 REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT)
num target prot opt source destination
The ip6tables default rules are essentially the same. |
contains 3 rules |
Set Default ip6tables Policy for Incoming Packets
[ref]ruleTo set the default policy to DROP (instead of ACCEPT) for
the built-in INPUT chain which processes incoming packets,
add or correct the following line in
/etc/sysconfig/ip6tables :
:INPUT DROP [0:0]
If changes were required, reload the ip6tables rules:
$ sudo service ip6tables reload Rationale:In ip6tables , the default policy is applied only after all
the applicable rules in the table are examined for a match. Setting the
default policy to DROP implements proper design for a firewall, i.e.
any packets which are not explicitly permitted should not be
accepted. Identifiers:
CCE-91342-6 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CIP-003-8 R4, CIP-003-8 R5, CIP-004-6 R3, AC-4, CM-7(b), CA-3(5), SC-7(21), CM-6(a), PR.IP-1, PR.PT-3, 1.4.1, 3.5.3.3.1 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if ( ! ( rpm --quiet -q nftables ) && ! ( rpm --quiet -q ufw ) && rpm --quiet -q iptables ); then
sed -i 's/^:INPUT ACCEPT.*/:INPUT DROP [0:0]/g' /etc/sysconfig/ip6tables
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set configuration for IPv6 loopback traffic
[ref]ruleConfigure the loopback interface to accept traffic.
Configure all other interfaces to deny traffic to the loopback
network. Warning:
Changing firewall settings while connected over network can
result in being locked out of the system. Rationale:Loopback traffic is generated between processes on machine and is
typically critical to operation of the system. The loopback interface
is the only place that loopback network traffic should be seen,
all other interfaces should ignore traffic on this network as an
anti-spoofing measure. Remediation Ansible snippet: (show)
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-91346-7
- PCI-DSS-Req-1.3
- PCI-DSSv4-1.4.1
- medium_severity
- set_ipv6_loopback_traffic
- name: Check if IPv6 is enabled
command: sysctl -n net.ipv6.conf.all.disable_ipv6
register: ipv6_status
failed_when: ipv6_status.stdout != "0"
when: ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
) and "iptables" in ansible_facts.packages )
tags:
- CCE-91346-7
- PCI-DSS-Req-1.3
- PCI-DSSv4-1.4.1
- medium_severity
- set_ipv6_loopback_traffic
- name: Allow incoming traffic on the loopback interface
ansible.builtin.iptables:
ipv6: true
chain: INPUT
in_interface: lo
jump: ACCEPT
when:
- ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
) and "iptables" in ansible_facts.packages )
- ipv6_status.stdout == '0'
tags:
- CCE-91346-7
- PCI-DSS-Req-1.3
- PCI-DSSv4-1.4.1
- medium_severity
- set_ipv6_loopback_traffic
- name: Allow outgoing traffic on the loopback interface
ansible.builtin.iptables:
ipv6: true
chain: OUTPUT
out_interface: lo
jump: ACCEPT
when:
- ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
) and "iptables" in ansible_facts.packages )
- ipv6_status.stdout == '0'
tags:
- CCE-91346-7
- PCI-DSS-Req-1.3
- PCI-DSSv4-1.4.1
- medium_severity
- set_ipv6_loopback_traffic
- name: Drop incoming traffic from the localhost
ansible.builtin.iptables:
ipv6: true
chain: INPUT
source: ::1
jump: DROP
when:
- ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
) and "iptables" in ansible_facts.packages )
- ipv6_status.stdout == '0'
tags:
- CCE-91346-7
- PCI-DSS-Req-1.3
- PCI-DSSv4-1.4.1
- medium_severity
- set_ipv6_loopback_traffic
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if ( ! ( rpm --quiet -q nftables ) && ! ( rpm --quiet -q ufw ) && rpm --quiet -q iptables ); then
if [ "$(sysctl -n net.ipv6.conf.all.disable_ipv6)" -eq 0 ]; then
# IPv6 is not disabled, so run the script
ip6tables -A INPUT -i lo -j ACCEPT
ip6tables -A OUTPUT -o lo -j ACCEPT
ip6tables -A INPUT -s ::1 -j DROP
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set configuration for loopback traffic
[ref]ruleConfigure the loopback interface to accept traffic.
Configure all other interfaces to deny traffic to the loopback
network. Warning:
Changing firewall settings while connected over network can
result in being locked out of the system. Rationale:Loopback traffic is generated between processes on machine and is
typically critical to operation of the system. The loopback interface
is the only place that loopback network traffic should be seen, all
other interfaces should ignore traffic on this network as an
anti-spoofing measure. Remediation Ansible snippet: (show)
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-91345-9
- PCI-DSS-Req-1.3
- PCI-DSSv4-1.4.1
- medium_severity
- set_loopback_traffic
- name: Allow incoming traffic on the loopback interface
ansible.builtin.iptables:
chain: INPUT
in_interface: lo
jump: ACCEPT
when: ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
) and "iptables" in ansible_facts.packages )
tags:
- CCE-91345-9
- PCI-DSS-Req-1.3
- PCI-DSSv4-1.4.1
- medium_severity
- set_loopback_traffic
- name: Allow outgoing traffic on the loopback interface
ansible.builtin.iptables:
chain: OUTPUT
out_interface: lo
jump: ACCEPT
when: ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
) and "iptables" in ansible_facts.packages )
tags:
- CCE-91345-9
- PCI-DSS-Req-1.3
- PCI-DSSv4-1.4.1
- medium_severity
- set_loopback_traffic
- name: Drop incoming traffic from the localhost
ansible.builtin.iptables:
chain: INPUT
source: 127.0.0.0/8
jump: DROP
when: ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
) and "iptables" in ansible_facts.packages )
tags:
- CCE-91345-9
- PCI-DSS-Req-1.3
- PCI-DSSv4-1.4.1
- medium_severity
- set_loopback_traffic
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if ( ! ( rpm --quiet -q nftables ) && ! ( rpm --quiet -q ufw ) && rpm --quiet -q iptables ); then
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
iptables -A INPUT -s 127.0.0.0/8 -j DROP
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
The system includes support for Internet Protocol
version 6. A major and often-mentioned improvement over IPv4 is its
enormous increase in the number of available addresses. Another
important feature is its support for automatic configuration of
many network settings. |
contains 1 rule |
Configure IPv6 Settings if Necessary
[ref]groupA major feature of IPv6 is the extent to which systems
implementing it can automatically configure their networking
devices using information from the network. From a security
perspective, manually configuring important configuration
information is preferable to accepting it from the network
in an unauthenticated fashion. |
contains 1 rule |
Disable Kernel Parameter for Accepting Source-Routed Packets on IPv6 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router, which can
be used to bypass network security measures. This requirement applies only to the
forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and
the system is functioning as a router.
Accepting source-routed packets in the IPv6 protocol has few legitimate
uses. It should be disabled unless it is absolutely required. Identifiers:
CCE-85653-4 References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9, APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv), DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4, Req-1.4.3, 1.4.2, SRG-OS-000480-GPOS-00227, SLES-15-040321, 3.3.1, SV-235017r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /run/sysctl.d/
- /etc/sysctl.d/
- /usr/local/lib/sysctl.d/
- /lib/sysctl.d/
contains: ^[\s]*net.ipv6.conf.default.accept_source_route.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85653-4
- DISA-STIG-SLES-15-040321
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_source_route
- name: Comment out any occurrences of net.ipv6.conf.default.accept_source_route from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv6.conf.default.accept_source_route
replace: '#net.ipv6.conf.default.accept_source_route'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85653-4
- DISA-STIG-SLES-15-040321
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_source_route
- name: Comment out any occurrences of net.ipv6.conf.default.accept_source_route from
/etc/sysctl.conf
replace:
path: /etc/sysctl.conf
regexp: ^[\s]*net.ipv6.conf.default.accept_source_route
replace: '#net.ipv6.conf.default.accept_source_route'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85653-4
- DISA-STIG-SLES-15-040321
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_source_route
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.accept_source_route is set
sysctl:
name: net.ipv6.conf.default.accept_source_route
value: '{{ sysctl_net_ipv6_conf_default_accept_source_route_value }}'
sysctl_file: /etc/sysctl.d/net_ipv6_conf_default_accept_source_route.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85653-4
- DISA-STIG-SLES-15-040321
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_source_route
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv6.conf.default.accept_source_route from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_source_route.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv6.conf.default.accept_source_route" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE='/etc/sysctl.d/net_ipv6_conf_default_accept_source_route.conf'
sysctl_net_ipv6_conf_default_accept_source_route_value='0'
#
# Set runtime for net.ipv6.conf.default.accept_source_route
#
/sbin/sysctl -q -n -w net.ipv6.conf.default.accept_source_route="$sysctl_net_ipv6_conf_default_accept_source_route_value"
#
# If net.ipv6.conf.default.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv6.conf.default.accept_source_route = value" to /etc/sysctl.conf
#
sed -i "/^$SYSCONFIG_VAR/d" /etc/sysctl.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_source_route")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_source_route_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.default.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
cce="CCE-85653-4"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "${SYSCONFIG_FILE}" >> "${SYSCONFIG_FILE}"
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Kernel Parameters Which Affect Networking
[ref]groupThe sysctl utility is used to set
parameters which affect the operation of the Linux kernel. Kernel parameters
which affect networking and have security implications are described here. |
contains 9 rules |
Network Related Kernel Runtime Parameters for Hosts and Routers
[ref]groupCertain kernel parameters should be set for systems which are
acting as either hosts or routers to improve the system's ability defend
against certain types of IPv4 protocol attacks. |
contains 6 rules |
Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.rp_filter kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.rp_filter=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.rp_filter = 1 Rationale:Enabling reverse path filtering drops packets with source addresses
that should not have been able to be received on the interface they were
received on. It should not be used on systems which are routers for
complicated networks, but is helpful for end hosts and routers serving small
networks. Identifiers:
CCE-91218-8 References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4, Req-1.4.3, 1.4.3, SRG-OS-000480-GPOS-00227, 3.3.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /run/sysctl.d/
- /etc/sysctl.d/
- /usr/local/lib/sysctl.d/
- /lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.rp_filter.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91218-8
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_rp_filter
- name: Comment out any occurrences of net.ipv4.conf.all.rp_filter from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.rp_filter
replace: '#net.ipv4.conf.all.rp_filter'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91218-8
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_rp_filter
- name: Comment out any occurrences of net.ipv4.conf.all.rp_filter from /etc/sysctl.conf
replace:
path: /etc/sysctl.conf
regexp: ^[\s]*net.ipv4.conf.all.rp_filter
replace: '#net.ipv4.conf.all.rp_filter'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91218-8
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_rp_filter
- name: XCCDF Value sysctl_net_ipv4_conf_all_rp_filter_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_rp_filter_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.rp_filter is set
sysctl:
name: net.ipv4.conf.all.rp_filter
value: '{{ sysctl_net_ipv4_conf_all_rp_filter_value }}'
sysctl_file: /etc/sysctl.d/net_ipv4_conf_all_rp_filter.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91218-8
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_rp_filter
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.all.rp_filter from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.rp_filter.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.rp_filter" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE='/etc/sysctl.d/net_ipv4_conf_all_rp_filter.conf'
sysctl_net_ipv4_conf_all_rp_filter_value='1'
#
# Set runtime for net.ipv4.conf.all.rp_filter
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.rp_filter="$sysctl_net_ipv4_conf_all_rp_filter_value"
#
# If net.ipv4.conf.all.rp_filter present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.rp_filter = value" to /etc/sysctl.conf
#
sed -i "/^$SYSCONFIG_VAR/d" /etc/sysctl.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.rp_filter")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_rp_filter_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.rp_filter\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.rp_filter\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
cce="CCE-91218-8"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "${SYSCONFIG_FILE}" >> "${SYSCONFIG_FILE}"
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable Kernel Parameter for Accepting Secure ICMP Redirects on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.secure_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.secure_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.secure_redirects = 0 Rationale:Accepting "secure" ICMP redirects (from those gateways listed as
default gateways) has few legitimate uses. It should be disabled unless it is
absolutely required. Identifiers:
CCE-91220-4 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-001503, CCI-001551, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.4.3, 1.4.3, SRG-OS-000480-GPOS-00227, 3.3.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /run/sysctl.d/
- /etc/sysctl.d/
- /usr/local/lib/sysctl.d/
- /lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.secure_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91220-4
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_secure_redirects
- name: Comment out any occurrences of net.ipv4.conf.all.secure_redirects from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.secure_redirects
replace: '#net.ipv4.conf.all.secure_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91220-4
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_secure_redirects
- name: Comment out any occurrences of net.ipv4.conf.all.secure_redirects from /etc/sysctl.conf
replace:
path: /etc/sysctl.conf
regexp: ^[\s]*net.ipv4.conf.all.secure_redirects
replace: '#net.ipv4.conf.all.secure_redirects'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91220-4
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_secure_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_all_secure_redirects_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_secure_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.secure_redirects is set
sysctl:
name: net.ipv4.conf.all.secure_redirects
value: '{{ sysctl_net_ipv4_conf_all_secure_redirects_value }}'
sysctl_file: /etc/sysctl.d/net_ipv4_conf_all_secure_redirects.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91220-4
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_secure_redirects
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.all.secure_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.secure_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.secure_redirects" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE='/etc/sysctl.d/net_ipv4_conf_all_secure_redirects.conf'
sysctl_net_ipv4_conf_all_secure_redirects_value='0'
#
# Set runtime for net.ipv4.conf.all.secure_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.secure_redirects="$sysctl_net_ipv4_conf_all_secure_redirects_value"
#
# If net.ipv4.conf.all.secure_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.all.secure_redirects = value" to /etc/sysctl.conf
#
sed -i "/^$SYSCONFIG_VAR/d" /etc/sysctl.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.secure_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_secure_redirects_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.secure_redirects\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.secure_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
cce="CCE-91220-4"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "${SYSCONFIG_FILE}" >> "${SYSCONFIG_FILE}"
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.accept_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages modify the
host's route table and are unauthenticated. An illicit ICMP redirect
message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should
be disabled unless absolutely required. Identifiers:
CCE-85652-6 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.4.3, 1.4.3, SRG-OS-000480-GPOS-00227, SLES-15-040340, 3.3.3, SV-235019r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /run/sysctl.d/
- /etc/sysctl.d/
- /usr/local/lib/sysctl.d/
- /lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.accept_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85652-6
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040340
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_redirects
- name: Comment out any occurrences of net.ipv4.conf.default.accept_redirects from
config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.accept_redirects
replace: '#net.ipv4.conf.default.accept_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85652-6
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040340
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_redirects
- name: Comment out any occurrences of net.ipv4.conf.default.accept_redirects from
/etc/sysctl.conf
replace:
path: /etc/sysctl.conf
regexp: ^[\s]*net.ipv4.conf.default.accept_redirects
replace: '#net.ipv4.conf.default.accept_redirects'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85652-6
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040340
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_default_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.accept_redirects is set
sysctl:
name: net.ipv4.conf.default.accept_redirects
value: '{{ sysctl_net_ipv4_conf_default_accept_redirects_value }}'
sysctl_file: /etc/sysctl.d/net_ipv4_conf_default_accept_redirects.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85652-6
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040340
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_redirects
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.default.accept_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.accept_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.default.accept_redirects" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE='/etc/sysctl.d/net_ipv4_conf_default_accept_redirects.conf'
sysctl_net_ipv4_conf_default_accept_redirects_value='0'
#
# Set runtime for net.ipv4.conf.default.accept_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.accept_redirects="$sysctl_net_ipv4_conf_default_accept_redirects_value"
#
# If net.ipv4.conf.default.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.conf.default.accept_redirects = value" to /etc/sysctl.conf
#
sed -i "/^$SYSCONFIG_VAR/d" /etc/sysctl.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.accept_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_accept_redirects_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
cce="CCE-85652-6"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "${SYSCONFIG_FILE}" >> "${SYSCONFIG_FILE}"
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable Kernel Parameter to Ignore ICMP Broadcast Echo Requests on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.icmp_echo_ignore_broadcasts kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.icmp_echo_ignore_broadcasts = 1 Rationale:Responding to broadcast (ICMP) echoes facilitates network mapping
and provides a vector for amplification attacks.
Ignoring ICMP echo requests (pings) sent to broadcast or multicast
addresses makes the system slightly more difficult to enumerate on the network. Identifiers:
CCE-91243-6 References:
1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.4.3, 1.4.2, SRG-OS-000480-GPOS-00227, 3.3.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /run/sysctl.d/
- /etc/sysctl.d/
- /usr/local/lib/sysctl.d/
- /lib/sysctl.d/
contains: ^[\s]*net.ipv4.icmp_echo_ignore_broadcasts.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91243-6
- CJIS-5.10.1.1
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_icmp_echo_ignore_broadcasts
- name: Comment out any occurrences of net.ipv4.icmp_echo_ignore_broadcasts from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.icmp_echo_ignore_broadcasts
replace: '#net.ipv4.icmp_echo_ignore_broadcasts'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91243-6
- CJIS-5.10.1.1
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_icmp_echo_ignore_broadcasts
- name: Comment out any occurrences of net.ipv4.icmp_echo_ignore_broadcasts from /etc/sysctl.conf
replace:
path: /etc/sysctl.conf
regexp: ^[\s]*net.ipv4.icmp_echo_ignore_broadcasts
replace: '#net.ipv4.icmp_echo_ignore_broadcasts'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91243-6
- CJIS-5.10.1.1
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_icmp_echo_ignore_broadcasts
- name: XCCDF Value sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value # promote to variable
set_fact:
sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.icmp_echo_ignore_broadcasts is set
sysctl:
name: net.ipv4.icmp_echo_ignore_broadcasts
value: '{{ sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value }}'
sysctl_file: /etc/sysctl.d/net_ipv4_icmp_echo_ignore_broadcasts.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91243-6
- CJIS-5.10.1.1
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_icmp_echo_ignore_broadcasts
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.icmp_echo_ignore_broadcasts from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.icmp_echo_ignore_broadcasts.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.icmp_echo_ignore_broadcasts" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE='/etc/sysctl.d/net_ipv4_icmp_echo_ignore_broadcasts.conf'
sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value='1'
#
# Set runtime for net.ipv4.icmp_echo_ignore_broadcasts
#
/sbin/sysctl -q -n -w net.ipv4.icmp_echo_ignore_broadcasts="$sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value"
#
# If net.ipv4.icmp_echo_ignore_broadcasts present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.icmp_echo_ignore_broadcasts = value" to /etc/sysctl.conf
#
sed -i "/^$SYSCONFIG_VAR/d" /etc/sysctl.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.icmp_echo_ignore_broadcasts")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.icmp_echo_ignore_broadcasts\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.icmp_echo_ignore_broadcasts\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
cce="CCE-91243-6"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "${SYSCONFIG_FILE}" >> "${SYSCONFIG_FILE}"
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable Kernel Parameter to Ignore Bogus ICMP Error Responses on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.icmp_ignore_bogus_error_responses kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.icmp_ignore_bogus_error_responses = 1 Rationale:Ignoring bogus ICMP error responses reduces
log size, although some activity would not be logged. Identifiers:
CCE-91224-6 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, Req-1.4.3, 1.4.2, SRG-OS-000480-GPOS-00227, 3.3.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /run/sysctl.d/
- /etc/sysctl.d/
- /usr/local/lib/sysctl.d/
- /lib/sysctl.d/
contains: ^[\s]*net.ipv4.icmp_ignore_bogus_error_responses.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91224-6
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_icmp_ignore_bogus_error_responses
- unknown_severity
- name: Comment out any occurrences of net.ipv4.icmp_ignore_bogus_error_responses
from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.icmp_ignore_bogus_error_responses
replace: '#net.ipv4.icmp_ignore_bogus_error_responses'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91224-6
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_icmp_ignore_bogus_error_responses
- unknown_severity
- name: Comment out any occurrences of net.ipv4.icmp_ignore_bogus_error_responses
from /etc/sysctl.conf
replace:
path: /etc/sysctl.conf
regexp: ^[\s]*net.ipv4.icmp_ignore_bogus_error_responses
replace: '#net.ipv4.icmp_ignore_bogus_error_responses'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91224-6
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_icmp_ignore_bogus_error_responses
- unknown_severity
- name: XCCDF Value sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value # promote to variable
set_fact:
sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.icmp_ignore_bogus_error_responses is set
sysctl:
name: net.ipv4.icmp_ignore_bogus_error_responses
value: '{{ sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value }}'
sysctl_file: /etc/sysctl.d/net_ipv4_icmp_ignore_bogus_error_responses.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91224-6
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- PCI-DSS-Req-1.4.3
- PCI-DSSv4-1.4.2
- disable_strategy
- low_complexity
- medium_disruption
- reboot_required
- sysctl_net_ipv4_icmp_ignore_bogus_error_responses
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.icmp_ignore_bogus_error_responses from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.icmp_ignore_bogus_error_responses.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.icmp_ignore_bogus_error_responses" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE='/etc/sysctl.d/net_ipv4_icmp_ignore_bogus_error_responses.conf'
sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value='1'
#
# Set runtime for net.ipv4.icmp_ignore_bogus_error_responses
#
/sbin/sysctl -q -n -w net.ipv4.icmp_ignore_bogus_error_responses="$sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value"
#
# If net.ipv4.icmp_ignore_bogus_error_responses present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.icmp_ignore_bogus_error_responses = value" to /etc/sysctl.conf
#
sed -i "/^$SYSCONFIG_VAR/d" /etc/sysctl.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.icmp_ignore_bogus_error_responses")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.icmp_ignore_bogus_error_responses\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.icmp_ignore_bogus_error_responses\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
cce="CCE-91224-6"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "${SYSCONFIG_FILE}" >> "${SYSCONFIG_FILE}"
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable Kernel Parameter to Use TCP Syncookies on Network Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.tcp_syncookies kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.tcp_syncookies=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.tcp_syncookies = 1 Rationale:A TCP SYN flood attack can cause a denial of service by filling a
system's TCP connection table with connections in the SYN_RCVD state.
Syncookies can be used to track a connection when a subsequent ACK is received,
verifying the initiator is attempting a valid connection and is not a flood
source. This feature is activated when a flood condition is detected, and
enables the system to continue servicing valid connection requests. Identifiers:
CCE-83283-2 References:
BP28(R22), 1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, CCI-001095, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), SC-5(1), SC-5(2), SC-5(3)(a), CM-6(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4, Req-1.4.1, 1.4.3, SRG-OS-000480-GPOS-00227, SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00071, SLES-15-010310, 3.3.8, SV-234829r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /run/sysctl.d/
- /etc/sysctl.d/
- /usr/local/lib/sysctl.d/
- /lib/sysctl.d/
contains: ^[\s]*net.ipv4.tcp_syncookies.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83283-2
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-010310
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(1)
- NIST-800-53-SC-5(2)
- NIST-800-53-SC-5(3)(a)
- PCI-DSS-Req-1.4.1
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_syncookies
- name: Comment out any occurrences of net.ipv4.tcp_syncookies from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.tcp_syncookies
replace: '#net.ipv4.tcp_syncookies'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83283-2
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-010310
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(1)
- NIST-800-53-SC-5(2)
- NIST-800-53-SC-5(3)(a)
- PCI-DSS-Req-1.4.1
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_syncookies
- name: Comment out any occurrences of net.ipv4.tcp_syncookies from /etc/sysctl.conf
replace:
path: /etc/sysctl.conf
regexp: ^[\s]*net.ipv4.tcp_syncookies
replace: '#net.ipv4.tcp_syncookies'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83283-2
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-010310
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(1)
- NIST-800-53-SC-5(2)
- NIST-800-53-SC-5(3)(a)
- PCI-DSS-Req-1.4.1
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_syncookies
- name: XCCDF Value sysctl_net_ipv4_tcp_syncookies_value # promote to variable
set_fact:
sysctl_net_ipv4_tcp_syncookies_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.tcp_syncookies is set
sysctl:
name: net.ipv4.tcp_syncookies
value: '{{ sysctl_net_ipv4_tcp_syncookies_value }}'
sysctl_file: /etc/sysctl.d/net_ipv4_tcp_syncookies.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83283-2
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-010310
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(1)
- NIST-800-53-SC-5(2)
- NIST-800-53-SC-5(3)(a)
- PCI-DSS-Req-1.4.1
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_syncookies
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.tcp_syncookies from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.tcp_syncookies.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.tcp_syncookies" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE='/etc/sysctl.d/net_ipv4_tcp_syncookies.conf'
sysctl_net_ipv4_tcp_syncookies_value='1'
#
# Set runtime for net.ipv4.tcp_syncookies
#
/sbin/sysctl -q -n -w net.ipv4.tcp_syncookies="$sysctl_net_ipv4_tcp_syncookies_value"
#
# If net.ipv4.tcp_syncookies present in /etc/sysctl.conf, change value to appropriate value
# else, add "net.ipv4.tcp_syncookies = value" to /etc/sysctl.conf
#
sed -i "/^$SYSCONFIG_VAR/d" /etc/sysctl.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.tcp_syncookies")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_tcp_syncookies_value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.tcp_syncookies\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.tcp_syncookies\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
cce="CCE-83283-2"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "${SYSCONFIG_FILE}" >> "${SYSCONFIG_FILE}"
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Network Parameters for Hosts Only
[ref]groupIf the system is not going to be used as a router, then setting certain
kernel parameters ensure that the host will not perform routing
of network traffic. |
contains 3 rules |
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.send_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.send_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages contain information
from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers. Identifiers:
CCE-85655-9 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, 1.4.5, SRG-OS-000480-GPOS-00227, SLES-15-040370, 3.2.2, SV-235023r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /run/sysctl.d/
- /etc/sysctl.d/
- /usr/local/lib/sysctl.d/
- /lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.all.send_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85655-9
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040370
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSSv4-1.4.5
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_send_redirects
- name: Comment out any occurrences of net.ipv4.conf.all.send_redirects from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.all.send_redirects
replace: '#net.ipv4.conf.all.send_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85655-9
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040370
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSSv4-1.4.5
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_send_redirects
- name: Comment out any occurrences of net.ipv4.conf.all.send_redirects from /etc/sysctl.conf
replace:
path: /etc/sysctl.conf
regexp: ^[\s]*net.ipv4.conf.all.send_redirects
replace: '#net.ipv4.conf.all.send_redirects'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85655-9
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040370
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSSv4-1.4.5
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_send_redirects
- name: Ensure sysctl net.ipv4.conf.all.send_redirects is set to 0
sysctl:
name: net.ipv4.conf.all.send_redirects
value: '0'
sysctl_file: /etc/sysctl.d/net_ipv4_conf_all_send_redirects.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85655-9
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040370
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSSv4-1.4.5
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_send_redirects
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.all.send_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.send_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.all.send_redirects" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE='/etc/sysctl.d/net_ipv4_conf_all_send_redirects.conf'
#
# Set runtime for net.ipv4.conf.all.send_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.all.send_redirects="0"
#
# If net.ipv4.conf.all.send_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.all.send_redirects = 0" to /etc/sysctl.conf
#
sed -i "/^$SYSCONFIG_VAR/d" /etc/sysctl.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.send_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.send_redirects\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.send_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
cce="CCE-85655-9"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "${SYSCONFIG_FILE}" >> "${SYSCONFIG_FILE}"
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.send_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.send_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages contain information
from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers. Identifiers:
CCE-85654-2 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, 1.4.5, SRG-OS-000480-GPOS-00227, SLES-15-040360, 3.2.2, SV-235022r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /run/sysctl.d/
- /etc/sysctl.d/
- /usr/local/lib/sysctl.d/
- /lib/sysctl.d/
contains: ^[\s]*net.ipv4.conf.default.send_redirects.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85654-2
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040360
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSSv4-1.4.5
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_send_redirects
- name: Comment out any occurrences of net.ipv4.conf.default.send_redirects from config
files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.conf.default.send_redirects
replace: '#net.ipv4.conf.default.send_redirects'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85654-2
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040360
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSSv4-1.4.5
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_send_redirects
- name: Comment out any occurrences of net.ipv4.conf.default.send_redirects from /etc/sysctl.conf
replace:
path: /etc/sysctl.conf
regexp: ^[\s]*net.ipv4.conf.default.send_redirects
replace: '#net.ipv4.conf.default.send_redirects'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85654-2
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040360
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSSv4-1.4.5
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_send_redirects
- name: Ensure sysctl net.ipv4.conf.default.send_redirects is set to 0
sysctl:
name: net.ipv4.conf.default.send_redirects
value: '0'
sysctl_file: /etc/sysctl.d/net_ipv4_conf_default_send_redirects.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85654-2
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040360
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- PCI-DSSv4-1.4.5
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_send_redirects
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.conf.default.send_redirects from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.send_redirects.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.conf.default.send_redirects" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE='/etc/sysctl.d/net_ipv4_conf_default_send_redirects.conf'
#
# Set runtime for net.ipv4.conf.default.send_redirects
#
/sbin/sysctl -q -n -w net.ipv4.conf.default.send_redirects="0"
#
# If net.ipv4.conf.default.send_redirects present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.conf.default.send_redirects = 0" to /etc/sysctl.conf
#
sed -i "/^$SYSCONFIG_VAR/d" /etc/sysctl.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.send_redirects")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.send_redirects\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.send_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
cce="CCE-85654-2"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "${SYSCONFIG_FILE}" >> "${SYSCONFIG_FILE}"
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable Kernel Parameter for IP Forwarding on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.ip_forward kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.ip_forward=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.ip_forward = 0 Warning:
Certain technologies such as virtual machines, containers, etc. rely on IPv4 forwarding to enable and use networking.
Disabling IPv4 forwarding would cause those technologies to stop working. Therefore, this rule should not be used in
profiles or benchmarks that target usage of IPv4 forwarding. Rationale:Routing protocol daemons are typically used on routers to exchange
network topology information with other routers. If this capability is used when
not required, system network information may be unnecessarily transmitted across
the network. Identifiers:
CCE-85709-4 References:
BP28(R22), 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-6(b), CM-6.1(iv), DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.3.1, Req-1.3.2, 1.4.3, SRG-OS-000480-GPOS-00227, SLES-15-040380, 3.2.1, SV-235024r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /run/sysctl.d/
- /etc/sysctl.d/
- /usr/local/lib/sysctl.d/
- /lib/sysctl.d/
contains: ^[\s]*net.ipv4.ip_forward.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85709-4
- DISA-STIG-SLES-15-040380
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSS-Req-1.3.1
- PCI-DSS-Req-1.3.2
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_forward
- name: Comment out any occurrences of net.ipv4.ip_forward from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*net.ipv4.ip_forward
replace: '#net.ipv4.ip_forward'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85709-4
- DISA-STIG-SLES-15-040380
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSS-Req-1.3.1
- PCI-DSS-Req-1.3.2
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_forward
- name: Comment out any occurrences of net.ipv4.ip_forward from /etc/sysctl.conf
replace:
path: /etc/sysctl.conf
regexp: ^[\s]*net.ipv4.ip_forward
replace: '#net.ipv4.ip_forward'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85709-4
- DISA-STIG-SLES-15-040380
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSS-Req-1.3.1
- PCI-DSS-Req-1.3.2
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_forward
- name: Ensure sysctl net.ipv4.ip_forward is set to 0
sysctl:
name: net.ipv4.ip_forward
value: '0'
sysctl_file: /etc/sysctl.d/net_ipv4_ip_forward.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85709-4
- DISA-STIG-SLES-15-040380
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSS-Req-1.3.1
- PCI-DSS-Req-1.3.2
- PCI-DSSv4-1.4.3
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_forward
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of net.ipv4.ip_forward from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.ip_forward.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "net.ipv4.ip_forward" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE='/etc/sysctl.d/net_ipv4_ip_forward.conf'
#
# Set runtime for net.ipv4.ip_forward
#
/sbin/sysctl -q -n -w net.ipv4.ip_forward="0"
#
# If net.ipv4.ip_forward present in /etc/sysctl.conf, change value to "0"
# else, add "net.ipv4.ip_forward = 0" to /etc/sysctl.conf
#
sed -i "/^$SYSCONFIG_VAR/d" /etc/sysctl.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.ip_forward")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.ip_forward\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.ip_forward\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
cce="CCE-85709-4"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "${SYSCONFIG_FILE}" >> "${SYSCONFIG_FILE}"
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
nftables
[ref]groupIf firewalld or iptables are being used in your environment, please follow the guidance in their
respective section and pass-over the guidance in this section.
nftables is a subsystem of the Linux kernel providing filtering and classification of network
packets/datagrams/frames and is the successor to iptables. The biggest change with the
successor nftables is its simplicity. With iptables, we have to configure every single rule and
use the syntax which can be compared with normal commands. With nftables, the simpler
syntax, much like BPF (Berkely Packet Filter) means shorter lines and less repetition.
Support for nftables should also be compiled into the kernel, together with the related
nftables modules.
It is available in Linux kernels >= 3.13. Please ensure that your kernel
supports nftables before choosing this option.
|
contains 3 rules |
Install nftables Package
[ref]rulenftables provides a new in-kernel packet classification framework that is based on a
network-specific Virtual Machine (VM) and a new nft userspace command line tool.
nftables reuses the existing Netfilter subsystems such as the existing hook infrastructure,
the connection tracking system, NAT, userspace queuing and logging subsystem.
The nftables package can be installed with the following command:
$ sudo zypper install nftables Rationale:nftables is a subsystem of the Linux kernel that can protect against threats
originating from within a corporate network to include malicious mobile code and poorly
configured software on a host. Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_nftables
class install_nftables {
package { 'nftables':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "nftables"
version = "*"
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure nftables is installed
package:
name: nftables
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-92469-6
- PCI-DSSv4-1.2.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_nftables_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "nftables"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify nftables Service is Disabled
[ref]rulenftables is a subsystem of the Linux kernel providing filtering and classification of network
packets/datagrams/frames and is the successor to iptables.
The nftables service can be disabled with the following command:
systemctl disable nftables Rationale:Running both firewalld and nftables may lead to conflict. nftables
is actually one of the backends for firewalld management tools. Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_nftables
class disable_nftables {
service {'nftables':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["nftables"]
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-92529-7
- PCI-DSSv4-1.2.1
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_nftables_disabled
- name: Block Disable service nftables
block:
- name: Disable service nftables
block:
- name: Disable service nftables
systemd:
name: nftables.service
enabled: 'no'
state: stopped
masked: 'yes'
rescue:
- name: Intentionally ignored previous 'Disable service nftables' failure, service
was already disabled
meta: noop
when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
"container"] and "firewalld" in ansible_facts.packages and "nftables" in ansible_facts.packages
)
tags:
- CCE-92529-7
- PCI-DSSv4-1.2.1
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_nftables_disabled
- name: Unit Socket Exists - nftables.socket
command: systemctl -q list-unit-files nftables.socket
register: socket_file_exists
changed_when: false
failed_when: socket_file_exists.rc not in [0, 1]
check_mode: false
when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
"container"] and "firewalld" in ansible_facts.packages and "nftables" in ansible_facts.packages
)
tags:
- CCE-92529-7
- PCI-DSSv4-1.2.1
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_nftables_disabled
- name: Disable socket nftables
systemd:
name: nftables.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
and "firewalld" in ansible_facts.packages and "nftables" in ansible_facts.packages
)
- socket_file_exists.stdout_lines is search("nftables.socket",multiline=True)
tags:
- CCE-92529-7
- PCI-DSSv4-1.2.1
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_nftables_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q firewalld && rpm --quiet -q nftables ); then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'nftables.service'
"$SYSTEMCTL_EXEC" disable 'nftables.service'
"$SYSTEMCTL_EXEC" mask 'nftables.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files nftables.socket; then
"$SYSTEMCTL_EXEC" stop 'nftables.socket'
"$SYSTEMCTL_EXEC" mask 'nftables.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'nftables.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure nftables Default Deny Firewall Policy
[ref]ruleBase chain policy is the default verdict that will be applied to packets reaching the end of
the chain. There are two policies: accept (Default) and drop. If the policy is set to accept,
the firewall will accept any packet that is not configured to be denied and the packet will
continue traversing the network stack. Warning:
Changing firewall settings while connected over network can result in being locked out
of the system. Rationale:It is easier to allow acceptable usage than to block unacceptable usage. |
Uncommon Network Protocols
[ref]groupThe system includes support for several network protocols which are not commonly used.
Although security vulnerabilities in kernel networking code are not frequently discovered,
the consequences can be dramatic. Ensuring uncommon network protocols are disabled
reduces the system's risk to attacks targeted at its implementation of those protocols. Warning:
Although these protocols are not commonly used, avoid disruption
in your network environment by ensuring they are not needed
prior to disabling them. |
contains 2 rules |
Disable DCCP Support
[ref]ruleThe Datagram Congestion Control Protocol (DCCP) is a
relatively new transport layer protocol, designed to support
streaming media and telephony.
To configure the system to prevent the dccp
kernel module from being loaded, add the following line to the file /etc/modprobe.d/dccp.conf :
install dccp /bin/true Rationale:Disabling DCCP protects
the system against exploitation of any flaws in its implementation. Identifiers:
CCE-91241-0 References:
11, 14, 3, 9, 5.10.1, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, CCI-001958, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, Req-1.4.2, 1.4.2, SRG-OS-000096-GPOS-00050, SRG-OS-000378-GPOS-00163, 3.4.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure kernel module 'dccp' is disabled
lineinfile:
create: true
dest: /etc/modprobe.d/dccp.conf
regexp: install\s+dccp
line: install dccp /bin/true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91241-0
- CJIS-5.10.1
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-1.4.2
- PCI-DSSv4-1.4.2
- disable_strategy
- kernel_module_dccp_disabled
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- name: Ensure kernel module 'dccp' is blacklisted
lineinfile:
create: true
dest: /etc/modprobe.d/dccp.conf
regexp: ^blacklist dccp$
line: blacklist dccp
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91241-0
- CJIS-5.10.1
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-1.4.2
- PCI-DSSv4-1.4.2
- disable_strategy
- kernel_module_dccp_disabled
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if LC_ALL=C grep -q -m 1 "^install dccp" /etc/modprobe.d/dccp.conf ; then
sed -i 's#^install dccp.*#install dccp /bin/true#g' /etc/modprobe.d/dccp.conf
else
echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/dccp.conf
echo "install dccp /bin/true" >> /etc/modprobe.d/dccp.conf
fi
if ! LC_ALL=C grep -q -m 1 "^blacklist dccp$" /etc/modprobe.d/dccp.conf ; then
echo "blacklist dccp" >> /etc/modprobe.d/dccp.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable SCTP Support
[ref]ruleThe Stream Control Transmission Protocol (SCTP) is a
transport layer protocol, designed to support the idea of
message-oriented communication, with several streams of messages
within one connection.
To configure the system to prevent the sctp
kernel module from being loaded, add the following line to the file /etc/modprobe.d/sctp.conf :
install sctp /bin/true Rationale:Disabling SCTP protects
the system against exploitation of any flaws in its implementation. Identifiers:
CCE-91242-8 References:
11, 14, 3, 9, 5.10.1, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, CCI-000381, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, Req-1.4.2, 1.4.2, SRG-OS-000095-GPOS-00049, SRG-OS-000480-GPOS-00227, 3.4.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure kernel module 'sctp' is disabled
lineinfile:
create: true
dest: /etc/modprobe.d/sctp.conf
regexp: install\s+sctp
line: install sctp /bin/true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91242-8
- CJIS-5.10.1
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-1.4.2
- PCI-DSSv4-1.4.2
- disable_strategy
- kernel_module_sctp_disabled
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- name: Ensure kernel module 'sctp' is blacklisted
lineinfile:
create: true
dest: /etc/modprobe.d/sctp.conf
regexp: ^blacklist sctp$
line: blacklist sctp
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91242-8
- CJIS-5.10.1
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-1.4.2
- PCI-DSSv4-1.4.2
- disable_strategy
- kernel_module_sctp_disabled
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if LC_ALL=C grep -q -m 1 "^install sctp" /etc/modprobe.d/sctp.conf ; then
sed -i 's#^install sctp.*#install sctp /bin/true#g' /etc/modprobe.d/sctp.conf
else
echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/sctp.conf
echo "install sctp /bin/true" >> /etc/modprobe.d/sctp.conf
fi
if ! LC_ALL=C grep -q -m 1 "^blacklist sctp$" /etc/modprobe.d/sctp.conf ; then
echo "blacklist sctp" >> /etc/modprobe.d/sctp.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Wireless Networking
[ref]groupWireless networking, such as 802.11
(WiFi) and Bluetooth, can present a security risk to sensitive or
classified systems and networks. Wireless networking hardware is
much more likely to be included in laptop or portable systems than
in desktops or servers.
Removal of hardware provides the greatest assurance that the wireless
capability remains disabled. Acquisition policies often include provisions to
prevent the purchase of equipment that will be used in sensitive spaces and
includes wireless capabilities. If it is impractical to remove the wireless
hardware, and policy permits the device to enter sensitive spaces as long
as wireless is disabled, efforts should instead focus on disabling wireless capability
via software. |
contains 1 rule |
Disable Wireless Through Software Configuration
[ref]groupIf it is impossible to remove the wireless hardware
from the device in question, disable as much of it as possible
through software. The following methods can disable software
support for wireless networking, but note that these methods do not
prevent malicious software or careless users from re-activating the
devices. |
contains 1 rule |
Deactivate Wireless Network Interfaces
[ref]ruleDeactivating wireless network interfaces should prevent normal usage of the wireless
capability.
Configure the system to disable wireless network interfaces by issuing the following
command for every active <WIFI-INTERFACE> in the system:
$ sudo wicked ifdown <WIFI-INTERFACE>
Also remove the configuration files for every wifi adapter from
/etc/wicked/ifconfig/<WIFI-INTERFACE>.xml to prevent future
connections.Rationale:The use of wireless networking can introduce many different attack vectors into
the organization's network. Common attack vectors such as malicious association
and ad hoc networks will allow an attacker to spoof a wireless access point
(AP), allowing validated systems to connect to the malicious AP and enabling the
attacker to monitor and record network traffic. These malicious APs can also
serve to create a man-in-the-middle attack or be used to create a denial of
service to valid network resources. Identifiers:
CCE-83286-5 References:
11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.1.16, CCI-000085, CCI-002418, CCI-002421, CCI-001443, CCI-001444, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, 1315, 1319, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-18(a), AC-18(3), CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.3.3, 1.3.3, 2.3, SRG-OS-000299-GPOS-00117, SRG-OS-000300-GPOS-00118, SRG-OS-000424-GPOS-00188, SRG-OS-000481-GPOS-000481, SLES-15-010380, 3.1.2, SV-234847r854193_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | false |
---|
Strategy: | unknown |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83286-5
- DISA-STIG-SLES-15-010380
- NIST-800-171-3.1.16
- NIST-800-53-AC-18(3)
- NIST-800-53-AC-18(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- PCI-DSS-Req-1.3.3
- PCI-DSSv4-1.3.3
- PCI-DSSv4-2.3
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- wireless_disable_interfaces
- name: Ensure NetworkManager is installed
ansible.builtin.package:
name: '{{ item }}'
state: present
with_items:
- NetworkManager
tags:
- CCE-83286-5
- DISA-STIG-SLES-15-010380
- NIST-800-171-3.1.16
- NIST-800-53-AC-18(3)
- NIST-800-53-AC-18(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- PCI-DSS-Req-1.3.3
- PCI-DSSv4-1.3.3
- PCI-DSSv4-2.3
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- wireless_disable_interfaces
- name: Deactivate Wireless Network Interfaces
command: nmcli radio wifi off
when: '''NetworkManager'' in ansible_facts.packages'
tags:
- CCE-83286-5
- DISA-STIG-SLES-15-010380
- NIST-800-171-3.1.16
- NIST-800-53-AC-18(3)
- NIST-800-53-AC-18(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- PCI-DSS-Req-1.3.3
- PCI-DSSv4-1.3.3
- PCI-DSSv4-2.3
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- wireless_disable_interfaces
Remediation Shell script: (show)
zypper install -y "NetworkManager"
nmcli radio all off
|
Ensure System is Not Acting as a Network Sniffer
[ref]ruleThe system should not be acting as a network sniffer, which can
capture all traffic on the network to which it is connected. Run the following
to determine if any interface is running in promiscuous mode:
$ ip link | grep PROMISC
Promiscuous mode of an interface can be disabled with the following command:
$ sudo ip link set dev device_name multicast off promisc off Rationale:Network interfaces in promiscuous mode allow for the capture of all network traffic
visible to the system. If unauthorized individuals can access these applications, it
may allow them to collect information such as logon IDs, passwords, and key exchanges
between systems.
If the system is being used to perform a network troubleshooting function, the use of these
tools must be documented with the Information Systems Security Manager (ISSM) and restricted
to only authorized personnel. Identifiers:
CCE-85656-7 References:
1, 11, 14, 3, 9, APO11.06, APO12.06, BAI03.10, BAI09.01, BAI09.02, BAI09.03, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.05, DSS04.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.2.3.4, 4.3.3.3.7, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, SR 7.8, A.11.1.2, A.11.2.4, A.11.2.5, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.16.1.6, A.8.1.1, A.8.1.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), CM-7(2), MA-3, DE.DP-5, ID.AM-1, PR.IP-1, PR.MA-1, PR.PT-3, 1.4.5, SRG-OS-000480-GPOS-00227, SLES-15-040390, SV-235027r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Ensure System is Not Acting as a Network Sniffer - Gather network interfaces
ansible.builtin.command:
cmd: ip link show
register: network_interfaces
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85656-7
- DISA-STIG-SLES-15-040390
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(2)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MA-3
- PCI-DSSv4-1.4.5
- low_complexity
- low_disruption
- medium_severity
- network_sniffer_disabled
- no_reboot_needed
- restrict_strategy
- name: Ensure System is Not Acting as a Network Sniffer - Disable promiscuous mode
ansible.builtin.command:
cmd: ip link set dev {{ item.split(':')[1] }} multicast off promisc off
loop: '{{ network_interfaces.stdout_lines }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- item.split(':') | length == 3
tags:
- CCE-85656-7
- DISA-STIG-SLES-15-040390
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(2)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MA-3
- PCI-DSSv4-1.4.5
- low_complexity
- low_disruption
- medium_severity
- network_sniffer_disabled
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
for interface in $(ip link show | grep -E '^[0-9]' | cut -d ":" -f 2); do
ip link set dev $interface multicast off promisc off
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
File Permissions and Masks
[ref]groupTraditional Unix security relies heavily on file and
directory permissions to prevent unauthorized users from reading or
modifying files to which they should not have access.
Several of the commands in this section search filesystems
for files or directories with certain characteristics, and are
intended to be run on every local partition on a given system.
When the variable PART appears in one of the commands below,
it means that the command is intended to be run repeatedly, with the
name of each local partition substituted for PART in turn.
The following command prints a list of all xfs partitions on the local
system, which is the default filesystem for SUSE Linux Enterprise 15
installations:
$ mount -t xfs | awk '{print $3}'
For any systems that use a different
local filesystem type, modify this command as appropriate. |
contains 31 rules |
Verify Permissions on Important Files and
Directories
[ref]groupPermissions for many files on a system must be set
restrictively to ensure sensitive information is properly protected.
This section discusses important
permission restrictions which can be verified
to ensure that no harmful discrepancies have
arisen. |
contains 23 rules |
Verify Permissions on Files with Local Account Information and Credentials
[ref]groupThe default restrictive permissions for files which act as
important security databases such as passwd , shadow ,
group , and gshadow files must be maintained. Many utilities
need read access to the passwd file in order to function properly, but
read access to the shadow file allows malicious attacks against system
passwords, and should never be enabled. |
contains 18 rules |
Verify Group Who Owns Backup group File
[ref]rule To properly set the group owner of /etc/group- , run the command: $ sudo chgrp root /etc/group- Rationale:The /etc/group- file is a backup file of /etc/group , and as such,
it contains information regarding groups that are configured on the system.
Protection of this file is important for system security. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group-
stat:
path: /etc/group-
register: file_exists
tags:
- CCE-91329-3
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_backup_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/group-
file:
path: /etc/group-
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91329-3
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_backup_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/group-
|
Verify Group Who Owns Backup passwd File
[ref]rule To properly set the group owner of /etc/passwd- , run the command: $ sudo chgrp root /etc/passwd- Rationale:The /etc/passwd- file is a backup file of /etc/passwd , and as such,
it contains information about the users that are configured on the system.
Protection of this file is critical for system security. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd-
stat:
path: /etc/passwd-
register: file_exists
tags:
- CCE-91323-6
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_backup_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/passwd-
file:
path: /etc/passwd-
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91323-6
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_backup_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/passwd-
|
Verify User Who Owns Backup shadow File
[ref]rule To properly set the group owner of /etc/shadow- , run the command: $ sudo chgrp shadow /etc/shadow- Rationale:The /etc/shadow- file is a backup file of /etc/shadow , and as such,
it contains the list of local system accounts and password hashes.
Protection of this file is critical for system security. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow-
stat:
path: /etc/shadow-
register: file_exists
tags:
- CCE-91327-7
- PCI-DSS-Req-8.7
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_backup_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 15 on /etc/shadow-
file:
path: /etc/shadow-
group: '15'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91327-7
- PCI-DSS-Req-8.7
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_backup_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 15 /etc/shadow-
|
Verify Group Who Owns group File
[ref]rule To properly set the group owner of /etc/group , run the command: $ sudo chgrp root /etc/group Rationale:The /etc/group file contains information regarding groups that are configured
on the system. Protection of this file is important for system security. Identifiers:
CCE-85801-9 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 2.2.6, SRG-OS-000480-GPOS-00227, 6.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group
stat:
path: /etc/group
register: file_exists
tags:
- CCE-85801-9
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/group
file:
path: /etc/group
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85801-9
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/group
|
Verify Group Who Owns passwd File
[ref]rule To properly set the group owner of /etc/passwd , run the command: $ sudo chgrp root /etc/passwd Rationale:The /etc/passwd file contains information about the users that are configured on
the system. Protection of this file is critical for system security. Identifiers:
CCE-85809-2 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 2.2.6, SRG-OS-000480-GPOS-00227, 6.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd
stat:
path: /etc/passwd
register: file_exists
tags:
- CCE-85809-2
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/passwd
file:
path: /etc/passwd
group: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85809-2
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 0 /etc/passwd
|
Verify Group Who Owns shadow File
[ref]rule To properly set the group owner of /etc/shadow , run the command: $ sudo chgrp shadow /etc/shadow Rationale:The /etc/shadow file stores password hashes. Protection of this file is
critical for system security. Identifiers:
CCE-85808-4 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 2.2.6, SRG-OS-000480-GPOS-00227, 6.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow
stat:
path: /etc/shadow
register: file_exists
tags:
- CCE-85808-4
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 15 on /etc/shadow
file:
path: /etc/shadow
group: '15'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85808-4
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chgrp 15 /etc/shadow
|
Verify User Who Owns Backup group File
[ref]rule To properly set the owner of /etc/group- , run the command: $ sudo chown root /etc/group- Rationale:The /etc/group- file is a backup file of /etc/group , and as such,
it contains information regarding groups that are configured on the system.
Protection of this file is important for system security. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group-
stat:
path: /etc/group-
register: file_exists
tags:
- CCE-91330-1
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_backup_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/group-
file:
path: /etc/group-
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91330-1
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_backup_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/group-
|
Verify User Who Owns Backup passwd File
[ref]rule To properly set the owner of /etc/passwd- , run the command: $ sudo chown root /etc/passwd- Rationale:The /etc/passwd- file is a backup file of /etc/passwd , and as such,
it contains information about the users that are configured on the system.
Protection of this file is critical for system security. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd-
stat:
path: /etc/passwd-
register: file_exists
tags:
- CCE-91324-4
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_backup_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/passwd-
file:
path: /etc/passwd-
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91324-4
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_backup_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/passwd-
|
Verify Group Who Owns Backup shadow File
[ref]rule To properly set the owner of /etc/shadow- , run the command: $ sudo chown root /etc/shadow- Rationale:The /etc/shadow- file is a backup file of /etc/shadow , and as such,
it contains the list of local system accounts and password hashes.
Protection of this file is critical for system security. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow-
stat:
path: /etc/shadow-
register: file_exists
tags:
- CCE-91326-9
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_backup_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/shadow-
file:
path: /etc/shadow-
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91326-9
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_backup_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/shadow-
|
Verify User Who Owns group File
[ref]rule To properly set the owner of /etc/group , run the command: $ sudo chown root /etc/group Rationale:The /etc/group file contains information regarding groups that are configured
on the system. Protection of this file is important for system security. Identifiers:
CCE-85802-7 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-002223, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 2.2.6, SRG-OS-000480-GPOS-00227, 6.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group
stat:
path: /etc/group
register: file_exists
tags:
- CCE-85802-7
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/group
file:
path: /etc/group
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85802-7
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/group
|
Verify User Who Owns passwd File
[ref]rule To properly set the owner of /etc/passwd , run the command: $ sudo chown root /etc/passwd Rationale:The /etc/passwd file contains information about the users that are configured on
the system. Protection of this file is critical for system security. Identifiers:
CCE-85806-8 References:
12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-002223, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 2.2.6, SRG-OS-000480-GPOS-00227, 6.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd
stat:
path: /etc/passwd
register: file_exists
tags:
- CCE-85806-8
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/passwd
file:
path: /etc/passwd
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85806-8
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/passwd
|
Verify User Who Owns shadow File
[ref]rule To properly set the owner of /etc/shadow , run the command: $ sudo chown root /etc/shadow Rationale:The /etc/shadow file contains the list of local
system accounts and stores password hashes. Protection of this file is
critical for system security. Failure to give ownership of this file
to root provides the designated owner with access to sensitive information
which could weaken the system security posture. Identifiers:
CCE-85807-6 References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-002223, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 2.2.6, SRG-OS-000480-GPOS-00227, 6.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow
stat:
path: /etc/shadow
register: file_exists
tags:
- CCE-85807-6
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/shadow
file:
path: /etc/shadow
owner: '0'
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85807-6
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chown 0 /etc/shadow
|
Verify Permissions on Backup group File
[ref]rule
To properly set the permissions of /etc/group- , run the command:
$ sudo chmod 0644 /etc/group- Rationale:The /etc/group- file is a backup file of /etc/group , and as such,
it contains information regarding groups that are configured on the system.
Protection of this file is important for system security. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group-
stat:
path: /etc/group-
register: file_exists
tags:
- CCE-91331-9
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_backup_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/group-
file:
path: /etc/group-
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91331-9
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_backup_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/group-
|
Verify Permissions on Backup passwd File
[ref]rule
To properly set the permissions of /etc/passwd- , run the command:
$ sudo chmod 0644 /etc/passwd- Rationale:The /etc/passwd- file is a backup file of /etc/passwd , and as such,
it contains information about the users that are configured on the system.
Protection of this file is critical for system security. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd-
stat:
path: /etc/passwd-
register: file_exists
tags:
- CCE-91325-1
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_backup_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/passwd-
file:
path: /etc/passwd-
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91325-1
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_backup_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/passwd-
|
Verify Permissions on Backup shadow File
[ref]rule
To properly set the permissions of /etc/shadow- , run the command:
$ sudo chmod 0000 /etc/shadow- Rationale:The /etc/shadow- file is a backup file of /etc/shadow , and as such,
it contains the list of local system accounts and password hashes.
Protection of this file is critical for system security. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow-
stat:
path: /etc/shadow-
register: file_exists
tags:
- CCE-91328-5
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_backup_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xwrs,g-xwrs,o-xwrt on /etc/shadow-
file:
path: /etc/shadow-
mode: u-xwrs,g-xwrs,o-xwrt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91328-5
- NIST-800-53-AC-6 (1)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_backup_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xwrs,g-xwrs,o-xwrt /etc/shadow-
|
Verify Permissions on group File
[ref]rule
To properly set the permissions of /etc/passwd , run the command:
$ sudo chmod 0644 /etc/passwd Rationale:The /etc/group file contains information regarding groups that are configured
on the system. Protection of this file is important for system security. Identifiers:
CCE-85803-5 References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-002223, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 2.2.6, SRG-OS-000480-GPOS-00227, 6.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/group
stat:
path: /etc/group
register: file_exists
tags:
- CCE-85803-5
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/group
file:
path: /etc/group
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85803-5
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_etc_group
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/group
|
Verify Permissions on passwd File
[ref]rule
To properly set the permissions of /etc/passwd , run the command:
$ sudo chmod 0644 /etc/passwd Rationale:If the /etc/passwd file is writable by a group-owner or the
world the risk of its compromise is increased. The file contains the list of
accounts on the system and associated information, and protection of this file
is critical for system security. Identifiers:
CCE-85805-0 References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-002223, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 2.2.6, SRG-OS-000480-GPOS-00227, 6.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/passwd
stat:
path: /etc/passwd
register: file_exists
tags:
- CCE-85805-0
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwt on /etc/passwd
file:
path: /etc/passwd
mode: u-xs,g-xws,o-xwt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85805-0
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_etc_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwt /etc/passwd
|
Verify Permissions on shadow File
[ref]rule
To properly set the permissions of /etc/shadow , run the command:
$ sudo chmod 0640 /etc/shadow Rationale:The /etc/shadow file contains the list of local
system accounts and stores password hashes. Protection of this file is
critical for system security. Failure to give ownership of this file
to root provides the designated owner with access to sensitive information
which could weaken the system security posture. Identifiers:
CCE-85804-3 References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-002223, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c, 2.2.6, SRG-OS-000480-GPOS-00227, 6.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/shadow
stat:
path: /etc/shadow
register: file_exists
tags:
- CCE-85804-3
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwrt on /etc/shadow
file:
path: /etc/shadow
mode: u-xs,g-xws,o-xwrt
when: file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-85804-3
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
chmod u-xs,g-xws,o-xwrt /etc/shadow
|
Verify that All World-Writable Directories Have Sticky Bits Set
[ref]ruleWhen the so-called 'sticky bit' is set on a directory,
only the owner of a given file may remove that file from the
directory. Without the sticky bit, any user with write access to a
directory may remove any file in the directory. Setting the sticky
bit prevents users from removing each other's files. In cases where
there is no reason for a directory to be world-writable, a better
solution is to remove that permission rather than to set the sticky
bit. However, if a directory is used by a particular application,
consult that application's documentation instead of blindly
changing modes.
To set the sticky bit on a world-writable directory DIR, run the
following command:
$ sudo chmod +t DIR Rationale:Failing to set the sticky bit on public directories allows unauthorized
users to delete files in the directory structure.
The only authorized public directories are those temporary directories
supplied with the system, or those designed to be temporary file
repositories. The setting is normally reserved for directories used by the
system, by users for temporary file storage (such as /tmp ), and
for directories requiring global read/write access. Identifiers:
CCE-83282-4 References:
BP28(R40), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001090, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000138-GPOS-00069, SLES-15-010300, 1.1.22, SV-234828r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Verify that All World-Writable Directories Have Sticky Bits Set - Define Excluded
(Non-Local) File Systems and Paths
ansible.builtin.set_fact:
excluded_fstypes:
- afs
- ceph
- cifs
- smb3
- smbfs
- sshfs
- ncpfs
- ncp
- nfs
- nfs4
- gfs
- gfs2
- glusterfs
- gpfs
- pvfs2
- ocfs2
- lustre
- davfs
- fuse.sshfs
excluded_paths:
- dev
- proc
- run
- sys
search_paths: []
tags:
- CCE-83282-4
- DISA-STIG-SLES-15-010300
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Verify that All World-Writable Directories Have Sticky Bits Set - Find Relevant
Root Directories Ignoring Pre-Defined Excluded Paths
ansible.builtin.find:
paths: /
file_type: directory
excludes: '{{ excluded_paths }}'
hidden: true
recurse: false
register: result_relevant_root_dirs
tags:
- CCE-83282-4
- DISA-STIG-SLES-15-010300
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Verify that All World-Writable Directories Have Sticky Bits Set - Include
Relevant Root Directories in a List of Paths to be Searched
ansible.builtin.set_fact:
search_paths: '{{ search_paths | union([item.path]) }}'
loop: '{{ result_relevant_root_dirs.files }}'
tags:
- CCE-83282-4
- DISA-STIG-SLES-15-010300
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Verify that All World-Writable Directories Have Sticky Bits Set - Increment
Search Paths List with Local Partitions Mount Points
ansible.builtin.set_fact:
search_paths: '{{ search_paths | union([item.mount]) }}'
loop: '{{ ansible_mounts }}'
when:
- item.fstype not in excluded_fstypes
- item.mount != '/'
tags:
- CCE-83282-4
- DISA-STIG-SLES-15-010300
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Verify that All World-Writable Directories Have Sticky Bits Set - Increment
Search Paths List with Local NFS File System Targets
ansible.builtin.set_fact:
search_paths: '{{ search_paths | union([item.device.split('':'')[1]]) }}'
loop: '{{ ansible_mounts }}'
when: item.device is search("localhost:")
tags:
- CCE-83282-4
- DISA-STIG-SLES-15-010300
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Verify that All World-Writable Directories Have Sticky Bits Set - Define Rule
Specific Facts
ansible.builtin.set_fact:
world_writable_dirs: []
tags:
- CCE-83282-4
- DISA-STIG-SLES-15-010300
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Verify that All World-Writable Directories Have Sticky Bits Set - Find All
Uncompliant Directories in Local File Systems
ansible.builtin.command:
cmd: find {{ item }} -xdev -type d ( -perm -0002 -a ! -perm -1000 )
loop: '{{ search_paths }}'
changed_when: false
register: result_found_dirs
tags:
- CCE-83282-4
- DISA-STIG-SLES-15-010300
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Verify that All World-Writable Directories Have Sticky Bits Set - Create List
of World Writable Directories Without Sticky Bit
ansible.builtin.set_fact:
world_writable_dirs: '{{ world_writable_dirs | union(item.stdout_lines) | list
}}'
loop: '{{ result_found_dirs.results }}'
tags:
- CCE-83282-4
- DISA-STIG-SLES-15-010300
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Verify that All World-Writable Directories Have Sticky Bits Set - Ensure Sticky
Bit is Set on Local World Writable Directories
ansible.builtin.file:
path: '{{ item }}'
mode: a+t
loop: '{{ world_writable_dirs }}'
tags:
- CCE-83282-4
- DISA-STIG-SLES-15-010300
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
df --local -P | awk '{if (NR!=1) print $6}' \
| xargs -I '$6' find '$6' -xdev -type d \
\( -perm -0002 -a ! -perm -1000 \) 2>/dev/null \
-exec chmod a+t {} +
|
Ensure No World-Writable Files Exist
[ref]ruleIt is generally a good idea to remove global (other) write
access to a file when it is discovered. However, check with
documentation for specific applications before making changes.
Also, monitor for recurring world-writable files, as these may be
symptoms of a misconfigured application or user account. Finally,
this applies to real files and not virtual files that are a part of
pseudo file systems such as sysfs or procfs . Rationale:Data in world-writable files can be modified by any
user on the system. In almost all circumstances, files can be
configured using a combination of user and group permissions to
support whatever legitimate access is needed without the risk
caused by world-writable files. Identifiers:
CCE-91233-7 References:
BP28(R40), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, 6.1.8 Remediation Shell script: (show)
find / -xdev -type f -perm -002 -exec chmod o-w {} \;
|
Ensure All Files Are Owned by a Group
[ref]ruleIf any files are not owned by a group, then the
cause of their lack of group-ownership should be investigated.
Following this, the files should be deleted or assigned to an
appropriate group. The following command will discover and print
any files on local partitions which do not belong to a valid group:
$ df --local -P | awk '{if (NR!=1) print $6}' | sudo xargs -I '{}' find '{}' -xdev -nogroup
To search all filesystems on a system including network mounted
filesystems the following command can be run manually for each partition:
$ sudo find PARTITION -xdev -nogroup Warning:
This rule only considers local groups.
If you have your groups defined outside /etc/group , the rule won't consider those. Rationale:Unowned files do not directly imply a security problem, but they are generally
a sign that something is amiss. They may
be caused by an intruder, by incorrect software installation or
draft software removal, or by failure to remove all files belonging
to a deleted account. The files should be repaired so they
will not cause problems when accounts are created in the future,
and the cause should be discovered and addressed. Identifiers:
CCE-85658-3 References:
BP28(R55), 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10, CCI-000366, CCI-002165, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3, 2.2.6, SRG-OS-000480-GPOS-00227, SLES-15-040410, 6.1.10, SV-235029r622137_rule |
Ensure All Files Are Owned by a User
[ref]ruleIf any files are not owned by a user, then the
cause of their lack of ownership should be investigated.
Following this, the files should be deleted or assigned to an
appropriate user. The following command will discover and print
any files on local partitions which do not belong to a valid user:
$ df --local -P | awk {'if (NR!=1) print $6'} | sudo xargs -I '{}' find '{}' -xdev -nouser
To search all filesystems on a system including network mounted
filesystems the following command can be run manually for each partition:
$ sudo find PARTITION -xdev -nouser Warning:
For this rule to evaluate centralized user accounts, getent must be working properly
so that running the command getent passwd returns a list of all users in your organization.
If using the System Security Services Daemon (SSSD), enumerate = true must be configured
in your organization's domain to return a complete list of users Warning:
Enabling this rule will result in slower scan times depending on the size of your organization
and number of centralized users. Rationale:Unowned files do not directly imply a security problem, but they are generally
a sign that something is amiss. They may
be caused by an intruder, by incorrect software installation or
draft software removal, or by failure to remove all files belonging
to a deleted account. The files should be repaired so they
will not cause problems when accounts are created in the future,
and the cause should be discovered and addressed. Identifiers:
CCE-85657-5 References:
BP28(R55), 11, 12, 13, 14, 15, 16, 18, 3, 5, 9, APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, CCI-000366, CCI-002165, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3, 2.2.6, SRG-OS-000480-GPOS-00227, SLES-15-040400, 6.1.9, SV-235028r622137_rule |
Verify permissions of log files
[ref]ruleAny operating system providing too much information in error messages
risks compromising the data and security of the structure, and content
of error messages needs to be carefully considered by the organization.
Organizations carefully consider the structure/content of error messages.
The extent to which information systems are able to identify and handle
error conditions is guided by organizational policy and operational
requirements. Information that could be exploited by adversaries includes,
for example, erroneous logon attempts with passwords entered by mistake
as the username, mission/business information that can be derived from
(if not stated explicitly by) information recorded, and personal
information, such as account numbers, social security numbers, and credit
card numbers. Rationale:The SUSE Linux Enterprise 15 must generate error messages that provide information
necessary for corrective actions without revealing information that could
be exploited by adversaries. Identifiers:
CCE-85755-7 References:
CCI-001312, SI-11(a), SI-11(b), SI-11.1(iii), PR.AC-4, PR.DS-5, 10.3.1, SRG-OS-000205-GPOS-00083, SLES-15-010340, 4.2.3, SV-234832r880884_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Find /var/log/ file(s) recursively
command: find -H /var/log/ -perm /u+xs,g+xws,o+xwrt ! -name "*[bw]tmp" ! -name
"*lastlog" -type f -regex ".*"
register: files_found
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-85755-7
- DISA-STIG-SLES-15-010340
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- NIST-800-53-SI-11.1(iii)
- PCI-DSSv4-10.3.1
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_var_log
- name: Set permissions for /var/log/ file(s)
file:
path: '{{ item }}'
mode: u-xs,g-xws,o-xwrt
state: file
with_items:
- '{{ files_found.stdout_lines }}'
tags:
- CCE-85755-7
- DISA-STIG-SLES-15-010340
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- NIST-800-53-SI-11.1(iii)
- PCI-DSSv4-10.3.1
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_var_log
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
find -H /var/log/ -perm /u+xs,g+xws,o+xwrt ! -name '*[bw]tmp' ! -name '*lastlog' -type f -regex '.*' -exec chmod u-xs,g-xws,o-xwrt {} \;
|
Restrict Dynamic Mounting and Unmounting of
Filesystems
[ref]groupLinux includes a number of facilities for the automated addition
and removal of filesystems on a running system. These facilities may be
necessary in many environments, but this capability also carries some risk -- whether direct
risk from allowing users to introduce arbitrary filesystems,
or risk that software flaws in the automated mount facility itself could
allow an attacker to compromise the system.
This command can be used to list the types of filesystems that are
available to the currently executing kernel:
$ find /lib/modules/`uname -r`/kernel/fs -type f -name '*.ko'
If these filesystems are not required then they can be explicitly disabled
in a configuratio file in /etc/modprobe.d . |
contains 1 rule |
Disable Modprobe Loading of USB Storage Driver
[ref]ruleTo prevent USB storage devices from being used, configure the kernel module loading system
to prevent automatic loading of the USB storage driver.
To configure the system to prevent the usb-storage
kernel module from being loaded, add the following line to the file /etc/modprobe.d/usb-storage.conf :
install usb-storage /bin/true
This will prevent the modprobe program from loading the usb-storage
module, but will not prevent an administrator (or another program) from using the
insmod program to load the module manually.Rationale:USB storage devices such as thumb drives can be used to introduce
malicious software. Identifiers:
CCE-83294-9 References:
1, 12, 15, 16, 5, APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.21, CCI-000366, CCI-000778, CCI-001958, 164.308(a)(3)(i), 164.308(a)(3)(ii)(A), 164.310(d)(1), 164.310(d)(2), 164.312(a)(1), 164.312(a)(2)(iv), 164.312(b), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, A.11.2.6, A.13.1.1, A.13.2.1, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, 3.4.2, SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227, SLES-15-010480, 1.1.23, SV-234856r854202_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure kernel module 'usb-storage' is disabled
lineinfile:
create: true
dest: /etc/modprobe.d/usb-storage.conf
regexp: install\s+usb-storage
line: install usb-storage /bin/true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83294-9
- DISA-STIG-SLES-15-010480
- NIST-800-171-3.1.21
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- PCI-DSSv4-3.4.2
- disable_strategy
- kernel_module_usb-storage_disabled
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- name: Ensure kernel module 'usb-storage' is blacklisted
lineinfile:
create: true
dest: /etc/modprobe.d/usb-storage.conf
regexp: ^blacklist usb-storage$
line: blacklist usb-storage
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83294-9
- DISA-STIG-SLES-15-010480
- NIST-800-171-3.1.21
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- PCI-DSSv4-3.4.2
- disable_strategy
- kernel_module_usb-storage_disabled
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if LC_ALL=C grep -q -m 1 "^install usb-storage" /etc/modprobe.d/usb-storage.conf ; then
sed -i 's#^install usb-storage.*#install usb-storage /bin/true#g' /etc/modprobe.d/usb-storage.conf
else
echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/usb-storage.conf
echo "install usb-storage /bin/true" >> /etc/modprobe.d/usb-storage.conf
fi
if ! LC_ALL=C grep -q -m 1 "^blacklist usb-storage$" /etc/modprobe.d/usb-storage.conf ; then
echo "blacklist usb-storage" >> /etc/modprobe.d/usb-storage.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Restrict Programs from Dangerous Execution Patterns
[ref]groupThe recommendations in this section are designed to
ensure that the system's features to protect against potentially
dangerous program execution are activated.
These protections are applied at the system initialization or
kernel level, and defend against certain types of badly-configured
or compromised programs. |
contains 7 rules |
Disable Core Dumps
[ref]groupA core dump file is the memory image of an executable
program when it was terminated by the operating system due to
errant behavior. In most cases, only software developers
legitimately need to access these files. The core dump files may
also contain sensitive information, or unnecessarily occupy large
amounts of disk space.
Once a hard limit is set in /etc/security/limits.conf , or
to a file within the /etc/security/limits.d/ directory, a
user cannot increase that limit within his or her own session. If access
to core dumps is required, consider restricting them to only
certain users or groups. See the limits.conf man page for more
information.
The core dumps of setuid programs are further protected. The
sysctl variable fs.suid_dumpable controls whether
the kernel allows core dumps from these programs at all. The default
value of 0 is recommended. |
contains 4 rules |
Disable core dump backtraces
[ref]ruleThe ProcessSizeMax option in [Coredump] section
of /etc/systemd/coredump.conf
specifies the maximum size in bytes of a core which will be processed.
Core dumps exceeding this size may be stored, but the backtrace will not
be generated. Warning:
If the /etc/systemd/coredump.conf file
does not already contain the [Coredump] section,
the value will not be configured correctly. Rationale:A core dump includes a memory image taken at the time the operating system
terminates an application. The memory image could contain sensitive data
and is generally useful only for developers or system operators trying to
debug problems.
Enabling core dumps on production systems is not recommended,
however there may be overriding operational requirements to enable advanced
debuging. Permitting temporary enablement of core dumps during such situations
should be reviewed through local needs and policy. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85745-8
- NIST-800-53-CM-6
- PCI-DSS-Req-3.2
- PCI-DSSv4-3.3.1
- coredump_disable_backtraces
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: 'Disable core dump backtraces: Make sure Coredump section exist in remediation
file'
ansible.builtin.lineinfile:
path: /etc/systemd/coredump.conf.d/oscap-autoremedy.conf
line: '[Coredump]'
create: true
when: '"systemd" in ansible_facts.packages'
tags:
- CCE-85745-8
- NIST-800-53-CM-6
- PCI-DSS-Req-3.2
- PCI-DSSv4-3.3.1
- coredump_disable_backtraces
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Disable core dump backtraces
block:
- name: Check for duplicate values
lineinfile:
path: /etc/systemd/coredump.conf.d/oscap-autoremedy.conf
create: true
regexp: ^\s*ProcessSizeMax\s*=\s*
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/systemd/coredump.conf.d/oscap-autoremedy.conf
lineinfile:
path: /etc/systemd/coredump.conf.d/oscap-autoremedy.conf
create: true
regexp: ^\s*ProcessSizeMax\s*=\s*
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/systemd/coredump.conf.d/oscap-autoremedy.conf
lineinfile:
path: /etc/systemd/coredump.conf.d/oscap-autoremedy.conf
create: true
regexp: ^\s*ProcessSizeMax\s*=\s*
line: ProcessSizeMax=0
state: present
insertafter: '[Coredump]'
when: '"systemd" in ansible_facts.packages'
tags:
- CCE-85745-8
- NIST-800-53-CM-6
- PCI-DSS-Req-3.2
- PCI-DSSv4-3.3.1
- coredump_disable_backtraces
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q systemd; then
mkdir -p /etc/systemd/coredump.conf.d/
if [ ! -f "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf" ]; then
echo "[Coredump]" > "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf"
fi
if [ -e "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf" ] ; then
LC_ALL=C sed -i "/^\s*ProcessSizeMax\s*=\s*/Id" "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf"
else
touch "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf"
cp "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf" "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf.bak"
# Insert at the end of the file
printf '%s\n' "ProcessSizeMax=0" >> "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf"
# Clean up after ourselves.
rm "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable storing core dump
[ref]ruleThe Storage option in [Coredump] section
of /etc/systemd/coredump.conf or /etc/systemd/coredump.conf.d/*.conf
can be set to none to disable storing core dumps permanently. Warning:
If the /etc/systemd/coredump.conf file
does not already contain the [Coredump] section,
the value will not be configured correctly. Rationale:A core dump includes a memory image taken at the time the operating system
terminates an application. The memory image could contain sensitive data
and is generally useful only for developers or system operators trying to
debug problems. Enabling core dumps on production systems is not recommended,
however there may be overriding operational requirements to enable advanced
debuging. Permitting temporary enablement of core dumps during such situations
should be reviewed through local needs and policy. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85746-6
- NIST-800-53-CM-6
- PCI-DSS-Req-3.2
- PCI-DSSv4-3.3.1
- coredump_disable_storage
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: 'Disable storing core dump: Make sure Coredump section exist in remediation
file'
ansible.builtin.lineinfile:
path: /etc/systemd/coredump.conf.d/oscap-autoremedy.conf
line: '[Coredump]'
create: true
when: '"systemd" in ansible_facts.packages'
tags:
- CCE-85746-6
- NIST-800-53-CM-6
- PCI-DSS-Req-3.2
- PCI-DSSv4-3.3.1
- coredump_disable_storage
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Disable storing core dump
block:
- name: Check for duplicate values
lineinfile:
path: /etc/systemd/coredump.conf.d/oscap-autoremedy.conf
create: true
regexp: ^\s*Storage\s*=\s*
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/systemd/coredump.conf.d/oscap-autoremedy.conf
lineinfile:
path: /etc/systemd/coredump.conf.d/oscap-autoremedy.conf
create: true
regexp: ^\s*Storage\s*=\s*
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/systemd/coredump.conf.d/oscap-autoremedy.conf
lineinfile:
path: /etc/systemd/coredump.conf.d/oscap-autoremedy.conf
create: true
regexp: ^\s*Storage\s*=\s*
line: Storage=none
state: present
insertafter: '[Coredump]'
when: '"systemd" in ansible_facts.packages'
tags:
- CCE-85746-6
- NIST-800-53-CM-6
- PCI-DSS-Req-3.2
- PCI-DSSv4-3.3.1
- coredump_disable_storage
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q systemd; then
mkdir -p /etc/systemd/coredump.conf.d/
if [ ! -f "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf" ]; then
echo "[Coredump]" > "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf"
fi
if [ -e "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf" ] ; then
LC_ALL=C sed -i "/^\s*Storage\s*=\s*/Id" "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf"
else
touch "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf"
cp "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf" "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf.bak"
# Insert at the end of the file
printf '%s\n' "Storage=none" >> "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf"
# Clean up after ourselves.
rm "/etc/systemd/coredump.conf.d/oscap-autoremedy.conf.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable Core Dumps for All Users
[ref]ruleTo disable core dumps for all users, add the following line to
/etc/security/limits.conf , or to a file within the
/etc/security/limits.d/ directory:
* hard core 0 Rationale:A core dump includes a memory image taken at the time the operating system
terminates an application. The memory image could contain sensitive data and is generally useful
only for developers trying to debug problems. Identifiers:
CCE-85740-9 References:
1, 12, 13, 15, 16, 2, 7, 8, APO13.01, BAI04.04, DSS01.03, DSS03.05, DSS05.07, CCI-000366, SR 6.2, SR 7.1, SR 7.2, A.12.1.3, A.17.2.1, CM-6, SC-7(10), DE.CM-1, PR.DS-4, 3.3.1, SRG-OS-000480-GPOS-00227, 1.6.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85740-9
- NIST-800-53-CM-6
- NIST-800-53-SC-7(10)
- PCI-DSSv4-3.3.1
- disable_users_coredumps
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Disable core dumps with limits
lineinfile:
dest: /etc/security/limits.conf
regexp: ^[^#].*core
line: '* hard core 0'
create: true
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85740-9
- NIST-800-53-CM-6
- NIST-800-53-SC-7(10)
- PCI-DSSv4-3.3.1
- disable_users_coredumps
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
SECURITY_LIMITS_FILE="/etc/security/limits.conf"
if grep -qE '^\s*\*\s+hard\s+core' $SECURITY_LIMITS_FILE; then
sed -ri 's/(hard\s+core\s+)[[:digit:]]+/\1 0/' $SECURITY_LIMITS_FILE
else
echo "* hard core 0" >> $SECURITY_LIMITS_FILE
fi
if ls /etc/security/limits.d/*.conf > /dev/null; then
sed -ri '/^\s*\*\s+hard\s+core/d' /etc/security/limits.d/*.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable Core Dumps for SUID programs
[ref]ruleTo set the runtime status of the fs.suid_dumpable kernel parameter, run the following command: $ sudo sysctl -w fs.suid_dumpable=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : fs.suid_dumpable = 0 Rationale:The core dump of a setuid program is more likely to contain
sensitive data, as the program itself runs with greater privileges than the
user who initiated execution of the program. Disabling the ability for any
setuid program to write a core file decreases the risk of unauthorized access
of such data. Identifiers:
CCE-91447-3 References:
BP28(R23), 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), SI-11(a), SI-11(b), 3.3.1, 1.6.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /run/sysctl.d/
- /etc/sysctl.d/
- /usr/local/lib/sysctl.d/
- /lib/sysctl.d/
contains: ^[\s]*fs.suid_dumpable.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91447-3
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- PCI-DSSv4-3.3.1
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_suid_dumpable
- name: Comment out any occurrences of fs.suid_dumpable from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*fs.suid_dumpable
replace: '#fs.suid_dumpable'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91447-3
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- PCI-DSSv4-3.3.1
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_suid_dumpable
- name: Comment out any occurrences of fs.suid_dumpable from /etc/sysctl.conf
replace:
path: /etc/sysctl.conf
regexp: ^[\s]*fs.suid_dumpable
replace: '#fs.suid_dumpable'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91447-3
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- PCI-DSSv4-3.3.1
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_suid_dumpable
- name: Ensure sysctl fs.suid_dumpable is set to 0
sysctl:
name: fs.suid_dumpable
value: '0'
sysctl_file: /etc/sysctl.d/fs_suid_dumpable.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91447-3
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- PCI-DSSv4-3.3.1
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_fs_suid_dumpable
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of fs.suid_dumpable from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*fs.suid_dumpable.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "fs.suid_dumpable" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE='/etc/sysctl.d/fs_suid_dumpable.conf'
#
# Set runtime for fs.suid_dumpable
#
/sbin/sysctl -q -n -w fs.suid_dumpable="0"
#
# If fs.suid_dumpable present in /etc/sysctl.conf, change value to "0"
# else, add "fs.suid_dumpable = 0" to /etc/sysctl.conf
#
sed -i "/^$SYSCONFIG_VAR/d" /etc/sysctl.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^fs.suid_dumpable")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^fs.suid_dumpable\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^fs.suid_dumpable\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
cce="CCE-91447-3"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "${SYSCONFIG_FILE}" >> "${SYSCONFIG_FILE}"
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable ExecShield
[ref]groupExecShield describes kernel features that provide
protection against exploitation of memory corruption errors such as buffer
overflows. These features include random placement of the stack and other
memory regions, prevention of execution in memory that should only hold data,
and special handling of text buffers. These protections are enabled by default
on 32-bit systems and controlled through sysctl variables
kernel.exec-shield and kernel.randomize_va_space . On the latest
64-bit systems, kernel.exec-shield cannot be enabled or disabled with
sysctl . |
contains 1 rule |
Enable Randomized Layout of Virtual Address Space
[ref]ruleTo set the runtime status of the kernel.randomize_va_space kernel parameter, run the following command: $ sudo sysctl -w kernel.randomize_va_space=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.randomize_va_space = 2 Rationale:Address space layout randomization (ASLR) makes it more difficult for an
attacker to predict the location of attack code they have introduced into a
process's address space during an attempt at exploitation. Additionally,
ASLR makes it more difficult for an attacker to know the location of
existing code in order to re-purpose it using return oriented programming
(ROP) techniques. Identifiers:
CCE-83300-4 References:
BP28(R23), 3.1.7, CCI-000366, CCI-002824, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), CIP-002-5 R1.1, CIP-002-5 R1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 4.1, CIP-004-6 4.2, CIP-004-6 R2.2.3, CIP-004-6 R2.2.4, CIP-004-6 R2.3, CIP-004-6 R4, CIP-005-6 R1, CIP-005-6 R1.1, CIP-005-6 R1.2, CIP-007-3 R3, CIP-007-3 R3.1, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R8.4, CIP-009-6 R.1.1, CIP-009-6 R4, SC-30, SC-30(2), CM-6(a), Req-2.2.1, 3.3.1, SRG-OS-000433-GPOS-00193, SRG-OS-000480-GPOS-00227, SRG-APP-000450-CTR-001105, SLES-15-010550, 1.6.3, SV-234862r854208_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: List /etc/sysctl.d/*.conf files
find:
paths:
- /run/sysctl.d/
- /etc/sysctl.d/
- /usr/local/lib/sysctl.d/
- /lib/sysctl.d/
contains: ^[\s]*kernel.randomize_va_space.*$
patterns: '*.conf'
file_type: any
register: find_sysctl_d
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83300-4
- DISA-STIG-SLES-15-010550
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- PCI-DSS-Req-2.2.1
- PCI-DSSv4-3.3.1
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_randomize_va_space
- name: Comment out any occurrences of kernel.randomize_va_space from config files
replace:
path: '{{ item.path }}'
regexp: ^[\s]*kernel.randomize_va_space
replace: '#kernel.randomize_va_space'
loop: '{{ find_sysctl_d.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83300-4
- DISA-STIG-SLES-15-010550
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- PCI-DSS-Req-2.2.1
- PCI-DSSv4-3.3.1
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_randomize_va_space
- name: Comment out any occurrences of kernel.randomize_va_space from /etc/sysctl.conf
replace:
path: /etc/sysctl.conf
regexp: ^[\s]*kernel.randomize_va_space
replace: '#kernel.randomize_va_space'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83300-4
- DISA-STIG-SLES-15-010550
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- PCI-DSS-Req-2.2.1
- PCI-DSSv4-3.3.1
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_randomize_va_space
- name: Ensure sysctl kernel.randomize_va_space is set to 2
sysctl:
name: kernel.randomize_va_space
value: '2'
sysctl_file: /etc/sysctl.d/kernel_randomize_va_space.conf
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83300-4
- DISA-STIG-SLES-15-010550
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- PCI-DSS-Req-2.2.1
- PCI-DSSv4-3.3.1
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_randomize_va_space
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Comment out any occurrences of kernel.randomize_va_space from /etc/sysctl.d/*.conf files
for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf; do
matching_list=$(grep -P '^(?!#).*[\s]*kernel.randomize_va_space.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
# comment out "kernel.randomize_va_space" matches to preserve user data
sed -i "s/^${escaped_entry}$/# &/g" $f
done <<< "$matching_list"
fi
done
#
# Set sysctl config file which to save the desired value
#
SYSCONFIG_FILE='/etc/sysctl.d/kernel_randomize_va_space.conf'
#
# Set runtime for kernel.randomize_va_space
#
/sbin/sysctl -q -n -w kernel.randomize_va_space="2"
#
# If kernel.randomize_va_space present in /etc/sysctl.conf, change value to "2"
# else, add "kernel.randomize_va_space = 2" to /etc/sysctl.conf
#
sed -i "/^$SYSCONFIG_VAR/d" /etc/sysctl.conf
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.randomize_va_space")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "2"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^kernel.randomize_va_space\\>" "${SYSCONFIG_FILE}"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^kernel.randomize_va_space\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
fi
cce="CCE-83300-4"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "${SYSCONFIG_FILE}" >> "${SYSCONFIG_FILE}"
printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable Execute Disable (XD) or No Execute (NX) Support on
x86 Systems
[ref]groupRecent processors in the x86 family support the
ability to prevent code execution on a per memory page basis.
Generically and on AMD processors, this ability is called No
Execute (NX), while on Intel processors it is called Execute
Disable (XD). This ability can help prevent exploitation of buffer
overflow vulnerabilities and should be activated whenever possible.
Extra steps must be taken to ensure that this protection is
enabled, particularly on 32-bit x86 systems. Other processors, such
as Itanium and POWER, have included such support since inception
and the standard kernel for those platforms supports the
feature. This is enabled by default on the latest Oracle Linux, Red Hat and
Fedora systems if supported by the hardware. |
contains 2 rules |
Enable NX or XD Support in the BIOS
[ref]ruleReboot the system and enter the BIOS or Setup configuration menu.
Navigate the BIOS configuration menu and make sure that the option is enabled. The setting may be located
under a Security section. Look for Execute Disable (XD) on Intel-based systems and No Execute (NX)
on AMD-based systems. Rationale:Computers with the ability to prevent this type of code execution frequently put an option in the BIOS that will
allow users to turn the feature on or off at will. Identifiers:
CCE-91254-3 References:
11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.7, CCI-002824, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, SC-39, CM-6(a), PR.IP-1, 2.2.1, SRG-OS-000433-GPOS-00192, SRG-APP-000450-CTR-001105, 1.6.2 |
Install PAE Kernel on Supported 32-bit x86 Systems
[ref]ruleSystems that are using the 64-bit x86 kernel package
do not need to install the kernel-PAE package because the 64-bit
x86 kernel already includes this support. However, if the system is
32-bit and also supports the PAE and NX features as
determined in the previous section, the kernel-PAE package should
be installed to enable XD or NX support.
The kernel-PAE package can be installed with the following command:
$ sudo zypper install kernel-PAE
The installation process should also have configured the
bootloader to load the new kernel at boot. Verify this after reboot
and modify /etc/default/grub if necessary.Warning:
The kernel-PAE package should not be
installed on older systems that do not support the XD or NX bit, as
8this may prevent them from booting.8 Rationale:On 32-bit systems that support the XD or NX bit, the vendor-supplied
PAE kernel is required to enable either Execute Disable (XD) or No Execute (NX) support. Identifiers:
CCE-91255-0 References:
BP28(R9), 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.7, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-6(a), PR.IP-1, 2.2.1, 1.6.2 |
SELinux
[ref]groupSELinux is a feature of the Linux kernel which can be
used to guard against misconfigured or compromised programs.
SELinux enforces the idea that programs should be limited in what
files they can access and what actions they can take.
The default SELinux policy, as configured on SUSE Linux Enterprise 15, has been
sufficiently developed and debugged that it should be usable on
almost any system with minimal configuration and a small
amount of system administrator training. This policy prevents
system services - including most of the common network-visible
services such as mail servers, FTP servers, and DNS servers - from
accessing files which those services have no valid reason to
access. This action alone prevents a huge amount of possible damage
from network attacks against services, from trojaned software, and
so forth.
This guide recommends that SELinux be enabled using the
default (targeted) policy on every SUSE Linux Enterprise 15 system, unless that
system has unusual requirements which make a stronger policy
appropriate. |
contains 5 rules |
Install libselinux Package
[ref]ruleThe libselinux package can be installed with the following command:
$ sudo zypper install libselinux Rationale:Security-enhanced Linux is a feature of the Linux kernel and a number of utilities
with enhanced security functionality designed to add mandatory access controls to Linux.
The libselinux package contains the core library of the Security-enhanced Linux system. Identifiers:
CCE-92490-2 References:
1.2.6 Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_libselinux1
class install_libselinux1 {
package { 'libselinux1':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "libselinux1"
version = "*"
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure libselinux1 is installed
package:
name: libselinux1
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-92490-2
- PCI-DSSv4-1.2.6
- enable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- package_libselinux_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "libselinux1"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure SELinux Not Disabled in /etc/default/grub
[ref]ruleSELinux can be disabled at boot time by an argument in
/etc/default/grub .
Remove any instances of selinux=0 from the kernel arguments in that
file to prevent SELinux from being disabled at boot. Rationale:Disabling a major host protection feature, such as SELinux, at boot time prevents
it from confining system services at boot time. Further, it increases
the chances that it will remain off during system operation. Identifiers:
CCE-91443-2 References:
1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-000022, CCI-000032, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-3, AC-3(3)(a), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, 1.2.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-91443-2
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- PCI-DSSv4-1.2.6
- grub2_enable_selinux
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure SELinux Not Disabled in /etc/default/grub - Find /etc/grub.d/ files
ansible.builtin.find:
paths:
- /etc/grub.d/
follow: true
register: result_grub_d
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
tags:
- CCE-91443-2
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- PCI-DSSv4-1.2.6
- grub2_enable_selinux
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure SELinux Not Disabled in /etc/default/grub - Ensure SELinux Not Disabled
in /etc/grub.d/ files
ansible.builtin.replace:
dest: '{{ item.path }}'
regexp: (selinux|enforcing)=0
with_items:
- '{{ result_grub_d.files }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
tags:
- CCE-91443-2
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- PCI-DSSv4-1.2.6
- grub2_enable_selinux
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure SELinux Not Disabled in /etc/default/grub - Check if /etc/grub2.cfg
exists
ansible.builtin.stat:
path: /etc/grub2.cfg
register: result_grub2_cfg_present
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
tags:
- CCE-91443-2
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- PCI-DSSv4-1.2.6
- grub2_enable_selinux
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure SELinux Not Disabled in /etc/default/grub - Check if /etc/default/grub
exists
ansible.builtin.stat:
path: /etc/default/grub
register: result_default_grub_present
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
tags:
- CCE-91443-2
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- PCI-DSSv4-1.2.6
- grub2_enable_selinux
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure SELinux Not Disabled in /etc/default/grub - Ensure SELinux Not Disabled
in /etc/grub2.cfg
ansible.builtin.replace:
dest: /etc/grub2.cfg
regexp: (selinux|enforcing)=0
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
- result_grub2_cfg_present.stat.exists
tags:
- CCE-91443-2
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- PCI-DSSv4-1.2.6
- grub2_enable_selinux
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure SELinux Not Disabled in /etc/default/grub - Ensure SELinux Not Disabled
in /etc/default/grub
ansible.builtin.replace:
dest: /etc/default/grub
regexp: (selinux|enforcing)=0
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"grub2" in ansible_facts.packages'
- result_default_grub_present.stat.exists
tags:
- CCE-91443-2
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- PCI-DSSv4-1.2.6
- grub2_enable_selinux
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2; }; then
sed -i --follow-symlinks "s/selinux=0//gI" /etc/default/grub /etc/grub2.cfg /etc/grub.d/*
sed -i --follow-symlinks "s/enforcing=0//gI" /etc/default/grub /etc/grub2.cfg /etc/grub.d/*
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure No Daemons are Unconfined by SELinux
[ref]ruleDaemons for which the SELinux policy does not contain rules will inherit the
context of the parent process. Because daemons are launched during
startup and descend from the init process, they inherit the unconfined_service_t context.
To check for unconfined daemons, run the following command:
$ sudo ps -eZ | grep "unconfined_service_t"
It should produce no output in a well-configured system.Warning:
Automatic remediation of this control is not available. Remediation
can be achieved by amending SELinux policy or stopping the unconfined
daemons as outlined above. Rationale:Daemons which run with the unconfined_service_t context may cause AVC denials,
or allow privileges that the daemon does not require. Identifiers:
CCE-91444-0 References:
1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9, APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, MEA02.01, 3.1.2, 3.1.5, 3.7.2, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-3(3)(a), AC-6, PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1, PR.PT-3, 1.2.6 |
Configure SELinux Policy
[ref]ruleThe SELinux targeted policy is appropriate for
general-purpose desktops and servers, as well as systems in many other roles.
To configure the system to use this policy, add or correct the following line
in /etc/selinux/config :
SELINUXTYPE=targeted
Other policies, such as mls , provide additional security labeling
and greater confinement but are not compatible with many general-purpose
use cases.Rationale:Setting the SELinux policy to targeted or a more specialized policy
ensures the system will confine processes that are likely to be
targeted for exploitation, such as network or system services.
Note: During the development or debugging of SELinux modules, it is common to
temporarily place non-production systems in permissive mode. In such
temporary cases, SELinux policies should be developed, and once work
is completed, the system should be reconfigured to
targeted . Identifiers:
CCE-91445-7 References:
BP28(R66), 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-002165, CCI-002696, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.2, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-004-6 R3.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AC-3, AC-3(3)(a), AU-9, SC-7(21), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, 1.2.6, SRG-OS-000445-GPOS-00199, SRG-APP-000233-CTR-000585 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_selinux_policy_name # promote to variable
set_fact:
var_selinux_policy_name: !!str targeted
tags:
- always
- name: Configure SELinux Policy
block:
- name: Check for duplicate values
lineinfile:
path: /etc/selinux/config
create: true
regexp: ^SELINUXTYPE=
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/selinux/config
lineinfile:
path: /etc/selinux/config
create: true
regexp: ^SELINUXTYPE=
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/selinux/config
lineinfile:
path: /etc/selinux/config
create: true
regexp: ^SELINUXTYPE=
line: SELINUXTYPE={{ var_selinux_policy_name }}
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91445-7
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- NIST-800-53-AU-9
- NIST-800-53-SC-7(21)
- PCI-DSSv4-1.2.6
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- selinux_policytype
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_selinux_policy_name='targeted'
if [ -e "/etc/selinux/config" ] ; then
LC_ALL=C sed -i "/^SELINUXTYPE=/Id" "/etc/selinux/config"
else
touch "/etc/selinux/config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/selinux/config"
cp "/etc/selinux/config" "/etc/selinux/config.bak"
# Insert at the end of the file
printf '%s\n' "SELINUXTYPE=$var_selinux_policy_name" >> "/etc/selinux/config"
# Clean up after ourselves.
rm "/etc/selinux/config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure SELinux State is Enforcing
[ref]ruleThe SELinux state should be set to enforcing at
system boot time. In the file /etc/selinux/config , add or correct the
following line to configure the system to boot into enforcing mode:
SELINUX=enforcing Rationale:Setting the SELinux state to enforcing ensures SELinux is able to confine
potentially compromised processes to the security policy, which is designed to
prevent them from causing damage to the system or further elevating their
privileges. Identifiers:
CCE-91446-5 References:
BP28(R4), BP28(R66), 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-001084, CCI-002165, CCI-002696, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.2, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-004-6 R3.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AC-3, AC-3(3)(a), AU-9, SC-7(21), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, SRG-OS-000445-GPOS-00199, SRG-OS-000134-GPOS-00068 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_selinux_state # promote to variable
set_fact:
var_selinux_state: !!str enforcing
tags:
- always
- name: Ensure SELinux State is Enforcing
block:
- name: Check for duplicate values
lineinfile:
path: /etc/selinux/config
create: true
regexp: ^SELINUX=
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/selinux/config
lineinfile:
path: /etc/selinux/config
create: true
regexp: ^SELINUX=
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/selinux/config
lineinfile:
path: /etc/selinux/config
create: true
regexp: ^SELINUX=
line: SELINUX={{ var_selinux_state }}
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91446-5
- NIST-800-171-3.1.2
- NIST-800-171-3.7.2
- NIST-800-53-AC-3
- NIST-800-53-AC-3(3)(a)
- NIST-800-53-AU-9
- NIST-800-53-SC-7(21)
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
- selinux_state
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_selinux_state='enforcing'
if [ -e "/etc/selinux/config" ] ; then
LC_ALL=C sed -i "/^SELINUX=/Id" "/etc/selinux/config"
else
touch "/etc/selinux/config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/selinux/config"
cp "/etc/selinux/config" "/etc/selinux/config.bak"
# Insert at the end of the file
printf '%s\n' "SELINUX=$var_selinux_state" >> "/etc/selinux/config"
# Clean up after ourselves.
rm "/etc/selinux/config.bak"
fixfiles onboot
fixfiles -f relabel
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Services
[ref]groupThe best protection against vulnerable software is running less software. This section describes how to review
the software which SUSE Linux Enterprise 15 installs on a system and disable software which is not needed. It
then enumerates the software packages installed on a default SUSE Linux Enterprise 15 system and provides guidance about which
ones can be safely disabled.
SUSE Linux Enterprise 15 provides a convenient minimal install option that essentially installs the bare necessities for a functional
system. When building SUSE Linux Enterprise 15 systems, it is highly recommended to select the minimal packages and then build up
the system from there. |
contains 70 rules |
Avahi Server
[ref]groupThe Avahi daemon implements the DNS Service Discovery
and Multicast DNS protocols, which provide service and host
discovery on a network. It allows a system to automatically
identify resources on the network, such as printers or web servers.
This capability is also known as mDNSresponder and is a major part
of Zeroconf networking. |
contains 1 rule |
Disable Avahi Server if Possible
[ref]groupBecause the Avahi daemon service keeps an open network
port, it is subject to network attacks.
Disabling it can reduce the system's vulnerability to such attacks. |
contains 1 rule |
Disable Avahi Server Software
[ref]rule
The avahi-daemon service can be disabled with the following command:
$ sudo systemctl mask --now avahi-daemon.service Rationale:Because the Avahi daemon service keeps an open network
port, it is subject to network attacks. Its functionality
is convenient but is only appropriate if the local network
can be trusted. Identifiers:
CCE-91321-0 References:
11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 2.2.4, 2.2.3 Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_avahi-daemon
class disable_avahi-daemon {
service {'avahi-daemon':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["avahi-daemon"]
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Block Disable service avahi-daemon
block:
- name: Disable service avahi-daemon
block:
- name: Disable service avahi-daemon
systemd:
name: avahi-daemon.service
enabled: 'no'
state: stopped
masked: 'yes'
rescue:
- name: Intentionally ignored previous 'Disable service avahi-daemon' failure,
service was already disabled
meta: noop
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91321-0
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_avahi-daemon_disabled
- name: Unit Socket Exists - avahi-daemon.socket
command: systemctl -q list-unit-files avahi-daemon.socket
register: socket_file_exists
changed_when: false
failed_when: socket_file_exists.rc not in [0, 1]
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91321-0
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_avahi-daemon_disabled
- name: Disable socket avahi-daemon
systemd:
name: avahi-daemon.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- socket_file_exists.stdout_lines is search("avahi-daemon.socket",multiline=True)
tags:
- CCE-91321-0
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_avahi-daemon_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'avahi-daemon.service'
"$SYSTEMCTL_EXEC" disable 'avahi-daemon.service'
"$SYSTEMCTL_EXEC" mask 'avahi-daemon.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files avahi-daemon.socket; then
"$SYSTEMCTL_EXEC" stop 'avahi-daemon.socket'
"$SYSTEMCTL_EXEC" mask 'avahi-daemon.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'avahi-daemon.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Cron and At Daemons
[ref]groupThe cron and at services are used to allow commands to
be executed at a later time. The cron service is required by almost
all systems to perform necessary maintenance tasks, while at may or
may not be required on a given system. Both daemons should be
configured defensively. |
contains 26 rules |
Restrict at and cron to Authorized Users if Necessary
[ref]groupThe /etc/cron.allow and /etc/at.allow files contain lists of
users who are allowed to use cron and at to delay execution of
processes. If these files exist and if the corresponding files
/etc/cron.deny and /etc/at.deny do not exist, then only users
listed in the relevant allow files can run the crontab and at commands
to submit jobs to be run at scheduled intervals. On many systems, only the
system administrator needs the ability to schedule jobs. Note that even if a
given user is not listed in cron.allow , cron jobs can still be run as
that user. The cron.allow file controls only administrative access
to the crontab command for scheduling and modifying cron jobs.
To restrict at and cron to only authorized users:
- Remove the
cron.deny file:$ sudo rm /etc/cron.deny - Edit
/etc/cron.allow , adding one line for each user allowed to use
the crontab command to create cron jobs. - Remove the
at.deny file:$ sudo rm /etc/at.deny - Edit
/etc/at.allow , adding one line for each user allowed to use
the at command to create at jobs.
|
contains 8 rules |
Ensure that /etc/at.deny does not exist
[ref]ruleThe file /etc/at.deny should not exist.
Use /etc/at.allow instead. Rationale:Access to at should be restricted.
It is easier to manage an allow list than a deny list. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Remove /etc/at.deny
file:
path: /etc/at.deny
state: absent
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91313-7
- PCI-DSSv4-2.2.6
- disable_strategy
- file_at_deny_not_exist
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
#!/bin/bash
if [[ -f /etc/at.deny ]]; then
rm /etc/at.deny
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure that /etc/cron.deny does not exist
[ref]ruleThe file /etc/cron.deny should not exist.
Use /etc/cron.allow instead. Rationale:Access to cron should be restricted.
It is easier to manage an allow list than a deny list. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Remove /etc/cron.deny
file:
path: /etc/cron.deny
state: absent
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91314-5
- PCI-DSSv4-2.2.6
- disable_strategy
- file_cron_deny_not_exist
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
#!/bin/bash
if [[ -f /etc/cron.deny ]]; then
rm /etc/cron.deny
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns /etc/at.allow file
[ref]ruleIf /etc/at.allow exists, it must be group-owned by root .
To properly set the group owner of /etc/at.allow , run the command:
$ sudo chgrp root /etc/at.allow Rationale:If the owner of the at.allow file is not set to root, the possibility exists for an
unauthorized user to view or edit sensitive information. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/at.allow
stat:
path: /etc/at.allow
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91315-2
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_at_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/at.allow
file:
path: /etc/at.allow
group: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91315-2
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_at_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chgrp 0 /etc/at.allow
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns /etc/cron.allow file
[ref]ruleIf /etc/cron.allow exists, it must be group-owned by root .
To properly set the group owner of /etc/cron.allow , run the command:
$ sudo chgrp root /etc/cron.allow Rationale:If the owner of the cron.allow file is not set to root, the possibility exists for an
unauthorized user to view or edit sensitive information. Identifiers:
CCE-91316-0 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/cron.allow
stat:
path: /etc/cron.allow
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91316-0
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_cron_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/cron.allow
file:
path: /etc/cron.allow
group: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91316-0
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_cron_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chgrp 0 /etc/cron.allow
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify User Who Owns /etc/at.allow file
[ref]ruleIf /etc/at.allow exists, it must be owned by root .
To properly set the owner of /etc/at.allow , run the command:
$ sudo chown root /etc/at.allow Rationale:If the owner of the at.allow file is not set to root, the possibility exists for an
unauthorized user to view or edit sensitive information. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/at.allow
stat:
path: /etc/at.allow
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91317-8
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_at_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/at.allow
file:
path: /etc/at.allow
owner: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91317-8
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_at_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chown 0 /etc/at.allow
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify User Who Owns /etc/cron.allow file
[ref]ruleIf /etc/cron.allow exists, it must be owned by root .
To properly set the owner of /etc/cron.allow , run the command:
$ sudo chown root /etc/cron.allow Rationale:If the owner of the cron.allow file is not set to root, the possibility exists for an
unauthorized user to view or edit sensitive information. Identifiers:
CCE-91318-6 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, 5.1.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/cron.allow
stat:
path: /etc/cron.allow
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91318-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_cron_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/cron.allow
file:
path: /etc/cron.allow
owner: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91318-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_owner_cron_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chown 0 /etc/cron.allow
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on /etc/at.allow file
[ref]ruleIf /etc/at.allow exists, it must have permissions 0640
or more restrictive.
To properly set the permissions of /etc/at.allow , run the command:
$ sudo chmod 0640 /etc/at.allow Rationale:If the permissions of the at.allow file are not set to 0640 or more restrictive,
the possibility exists for an unauthorized user to view or edit sensitive information. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/at.allow
stat:
path: /etc/at.allow
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91319-4
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_at_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwrt on /etc/at.allow
file:
path: /etc/at.allow
mode: u-xs,g-xws,o-xwrt
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91319-4
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_at_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chmod u-xs,g-xws,o-xwrt /etc/at.allow
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on /etc/cron.allow file
[ref]ruleIf /etc/cron.allow exists, it must have permissions 0640
or more restrictive.
To properly set the permissions of /etc/cron.allow , run the command:
$ sudo chmod 0640 /etc/cron.allow Rationale:If the permissions of the cron.allow file are not set to 0640 or more restrictive,
the possibility exists for an unauthorized user to view or edit sensitive information. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/cron.allow
stat:
path: /etc/cron.allow
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91320-2
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_cron_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xws,o-xwrt on /etc/cron.allow
file:
path: /etc/cron.allow
mode: u-xs,g-xws,o-xwrt
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91320-2
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_cron_allow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chmod u-xs,g-xws,o-xwrt /etc/cron.allow
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns cron.d
[ref]rule
To properly set the group owner of /etc/cron.d , run the command:
$ sudo chgrp root /etc/cron.d Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-91391-3 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure group owner on /etc/cron.d/
file:
path: /etc/cron.d/
state: directory
group: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91391-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_cron_d
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.d/ -maxdepth 1 -type d -exec chgrp 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns cron.daily
[ref]rule
To properly set the group owner of /etc/cron.daily , run the command:
$ sudo chgrp root /etc/cron.daily Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-91385-5 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure group owner on /etc/cron.daily/
file:
path: /etc/cron.daily/
state: directory
group: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91385-5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_cron_daily
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.daily/ -maxdepth 1 -type d -exec chgrp 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns cron.hourly
[ref]rule
To properly set the group owner of /etc/cron.hourly , run the command:
$ sudo chgrp root /etc/cron.hourly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-91382-2 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure group owner on /etc/cron.hourly/
file:
path: /etc/cron.hourly/
state: directory
group: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91382-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_cron_hourly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.hourly/ -maxdepth 1 -type d -exec chgrp 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns cron.monthly
[ref]rule
To properly set the group owner of /etc/cron.monthly , run the command:
$ sudo chgrp root /etc/cron.monthly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-91388-9 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure group owner on /etc/cron.monthly/
file:
path: /etc/cron.monthly/
state: directory
group: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91388-9
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_cron_monthly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.monthly/ -maxdepth 1 -type d -exec chgrp 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns cron.weekly
[ref]rule
To properly set the group owner of /etc/cron.weekly , run the command:
$ sudo chgrp root /etc/cron.weekly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-91386-3 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure group owner on /etc/cron.weekly/
file:
path: /etc/cron.weekly/
state: directory
group: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91386-3
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_cron_weekly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.weekly/ -maxdepth 1 -type d -exec chgrp 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Group Who Owns Crontab
[ref]rule
To properly set the group owner of /etc/crontab , run the command:
$ sudo chgrp root /etc/crontab Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-91380-6 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/crontab
stat:
path: /etc/crontab
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91380-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure group owner 0 on /etc/crontab
file:
path: /etc/crontab
group: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91380-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_groupowner_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chgrp 0 /etc/crontab
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on cron.d
[ref]rule
To properly set the owner of /etc/cron.d , run the command:
$ sudo chown root /etc/cron.d Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct user to prevent unauthorized changes. Identifiers:
CCE-91390-5 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure owner on directory /etc/cron.d/
file:
path: /etc/cron.d/
state: directory
owner: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91390-5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_cron_d
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.d/ -maxdepth 1 -type d -exec chown 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on cron.daily
[ref]rule
To properly set the owner of /etc/cron.daily , run the command:
$ sudo chown root /etc/cron.daily Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct user to prevent unauthorized changes. Identifiers:
CCE-91384-8 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure owner on directory /etc/cron.daily/
file:
path: /etc/cron.daily/
state: directory
owner: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91384-8
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_cron_daily
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.daily/ -maxdepth 1 -type d -exec chown 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on cron.hourly
[ref]rule
To properly set the owner of /etc/cron.hourly , run the command:
$ sudo chown root /etc/cron.hourly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct user to prevent unauthorized changes. Identifiers:
CCE-91383-0 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure owner on directory /etc/cron.hourly/
file:
path: /etc/cron.hourly/
state: directory
owner: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91383-0
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_cron_hourly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.hourly/ -maxdepth 1 -type d -exec chown 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on cron.monthly
[ref]rule
To properly set the owner of /etc/cron.monthly , run the command:
$ sudo chown root /etc/cron.monthly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct user to prevent unauthorized changes. Identifiers:
CCE-91389-7 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure owner on directory /etc/cron.monthly/
file:
path: /etc/cron.monthly/
state: directory
owner: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91389-7
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_cron_monthly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.monthly/ -maxdepth 1 -type d -exec chown 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on cron.weekly
[ref]rule
To properly set the owner of /etc/cron.weekly , run the command:
$ sudo chown root /etc/cron.weekly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct user to prevent unauthorized changes. Identifiers:
CCE-91387-1 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Ensure owner on directory /etc/cron.weekly/
file:
path: /etc/cron.weekly/
state: directory
owner: '0'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91387-1
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_cron_weekly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.weekly/ -maxdepth 1 -type d -exec chown 0 {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Owner on crontab
[ref]rule
To properly set the owner of /etc/crontab , run the command:
$ sudo chown root /etc/crontab Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should be owned by the
correct user to prevent unauthorized changes. Identifiers:
CCE-91381-4 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/crontab
stat:
path: /etc/crontab
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91381-4
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner 0 on /etc/crontab
file:
path: /etc/crontab
owner: '0'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91381-4
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chown 0 /etc/crontab
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on cron.d
[ref]rule
To properly set the permissions of /etc/cron.d , run the command:
$ sudo chmod 0700 /etc/cron.d Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the
correct access rights to prevent unauthorized changes. Identifiers:
CCE-91304-6 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Find /etc/cron.d/ file(s)
command: 'find -H /etc/cron.d/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type d '
register: files_found
changed_when: false
failed_when: false
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91304-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_cron_d
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /etc/cron.d/ file(s)
file:
path: '{{ item }}'
mode: u-s,g-xwrs,o-xwrt
state: directory
with_items:
- '{{ files_found.stdout_lines }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91304-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_cron_d
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.d/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type d -exec chmod u-s,g-xwrs,o-xwrt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on cron.daily
[ref]rule
To properly set the permissions of /etc/cron.daily , run the command:
$ sudo chmod 0700 /etc/cron.daily Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the
correct access rights to prevent unauthorized changes. Identifiers:
CCE-91301-2 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.4 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Find /etc/cron.daily/ file(s)
command: 'find -H /etc/cron.daily/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type d '
register: files_found
changed_when: false
failed_when: false
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91301-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_cron_daily
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /etc/cron.daily/ file(s)
file:
path: '{{ item }}'
mode: u-s,g-xwrs,o-xwrt
state: directory
with_items:
- '{{ files_found.stdout_lines }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91301-2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_cron_daily
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.daily/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type d -exec chmod u-s,g-xwrs,o-xwrt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on cron.hourly
[ref]rule
To properly set the permissions of /etc/cron.hourly , run the command:
$ sudo chmod 0700 /etc/cron.hourly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the
correct access rights to prevent unauthorized changes. Identifiers:
CCE-91300-4 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.3 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Find /etc/cron.hourly/ file(s)
command: 'find -H /etc/cron.hourly/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type
d '
register: files_found
changed_when: false
failed_when: false
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91300-4
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_cron_hourly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /etc/cron.hourly/ file(s)
file:
path: '{{ item }}'
mode: u-s,g-xwrs,o-xwrt
state: directory
with_items:
- '{{ files_found.stdout_lines }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91300-4
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_cron_hourly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.hourly/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type d -exec chmod u-s,g-xwrs,o-xwrt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on cron.monthly
[ref]rule
To properly set the permissions of /etc/cron.monthly , run the command:
$ sudo chmod 0700 /etc/cron.monthly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the
correct access rights to prevent unauthorized changes. Identifiers:
CCE-91303-8 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.6 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Find /etc/cron.monthly/ file(s)
command: 'find -H /etc/cron.monthly/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type
d '
register: files_found
changed_when: false
failed_when: false
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91303-8
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_cron_monthly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /etc/cron.monthly/ file(s)
file:
path: '{{ item }}'
mode: u-s,g-xwrs,o-xwrt
state: directory
with_items:
- '{{ files_found.stdout_lines }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91303-8
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_cron_monthly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.monthly/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type d -exec chmod u-s,g-xwrs,o-xwrt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on cron.weekly
[ref]rule
To properly set the permissions of /etc/cron.weekly , run the command:
$ sudo chmod 0700 /etc/cron.weekly Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the
correct access rights to prevent unauthorized changes. Identifiers:
CCE-91302-0 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.5 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Find /etc/cron.weekly/ file(s)
command: 'find -H /etc/cron.weekly/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type
d '
register: files_found
changed_when: false
failed_when: false
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91302-0
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_cron_weekly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /etc/cron.weekly/ file(s)
file:
path: '{{ item }}'
mode: u-s,g-xwrs,o-xwrt
state: directory
with_items:
- '{{ files_found.stdout_lines }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91302-0
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_cron_weekly
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/cron.weekly/ -maxdepth 1 -perm /u+s,g+xwrs,o+xwrt -type d -exec chmod u-s,g-xwrs,o-xwrt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on crontab
[ref]rule
To properly set the permissions of /etc/crontab , run the command:
$ sudo chmod 0600 /etc/crontab Rationale:Service configuration files enable or disable features of their respective services that if configured incorrectly
can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the
correct access rights to prevent unauthorized changes. Identifiers:
CCE-91299-8 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.1.2 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/crontab
stat:
path: /etc/crontab
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91299-8
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xwrs,o-xwrt on /etc/crontab
file:
path: /etc/crontab
mode: u-xs,g-xwrs,o-xwrt
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91299-8
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chmod u-xs,g-xwrs,o-xwrt /etc/crontab
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
The Dynamic Host Configuration Protocol (DHCP) allows
systems to request and obtain an IP address and other configuration
parameters from a server.
This guide recommends configuring networking on clients by manually editing
the appropriate files under /etc/sysconfig . Use of DHCP can make client
systems vulnerable to compromise by rogue DHCP servers, and should be avoided
unless necessary. If using DHCP is necessary, however, there are best practices
that should be followed to minimize security risk. |
contains 1 rule |
Disable DHCP Server
[ref]groupThe DHCP server dhcpd is not installed or activated by
default. If the software was installed and activated, but the
system does not need to act as a DHCP server, it should be disabled
and removed. |
contains 1 rule |
Uninstall DHCP Server Package
[ref]ruleIf the system does not need to act as a DHCP server,
the dhcp package can be uninstalled.
The dhcp-server package can be removed with the following command:
$ sudo zypper remove dhcp-server Rationale:Removing the DHCP server ensures that it cannot be easily or
accidentally reactivated and disrupt network operation. Identifiers:
CCE-85759-9 References:
BP28(R1), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 2.2.4, 2.2.5 Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_dhcp-server
class remove_dhcp-server {
package { 'dhcp-server':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure dhcp-server is removed
package:
name: dhcp-server
state: absent
tags:
- CCE-85759-9
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_dhcp_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove dhcp-server
# from the system, and may remove any packages
# that depend on dhcp-server. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "dhcp-server"
|
Mail Server Software
[ref]groupMail servers are used to send and receive email over the network.
Mail is a very common service, and Mail Transfer Agents (MTAs) are obvious
targets of network attack.
Ensure that systems are not running MTAs unnecessarily,
and configure needed MTAs as defensively as possible.
Very few systems at any site should be configured to directly receive email over the
network. Users should instead use mail client programs to retrieve email
from a central server that supports protocols such as IMAP or POP3.
However, it is normal for most systems to be independently capable of sending email,
for instance so that cron jobs can report output to an administrator.
Most MTAs, including Postfix, support a submission-only mode in which mail can be sent from
the local system to a central site MTA (or directly delivered to a local account),
but the system still cannot receive mail directly over a network.
The alternatives program in SUSE Linux Enterprise 15 permits selection of other mail server software
(such as Sendmail), but Postfix is the default and is preferred.
Postfix was coded with security in mind and can also be more effectively contained by
SELinux as its modular design has resulted in separate processes performing specific actions.
More information is available on its website,
http://www.postfix.org. |
contains 1 rule |
Configure SMTP For Mail Clients
[ref]groupThis section discusses settings for Postfix in a submission-only
e-mail configuration. |
contains 1 rule |
Disable Postfix Network Listening
[ref]ruleEdit the file /etc/postfix/main.cf to ensure that only the following
inet_interfaces line appears:
inet_interfaces = loopback-only Rationale:This ensures postfix accepts mail messages
(such as cron job reports) from the local system only,
and not from the network, which protects it from network attack. Identifiers:
CCE-91280-8 References:
BP28(R48), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000382, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, 1.4.2, 2.2.16 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_postfix_inet_interfaces # promote to variable
set_fact:
var_postfix_inet_interfaces: !!str loopback-only
tags:
- always
- name: Gather list of packages
package_facts:
manager: auto
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ''
tags:
- CCE-91280-8
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-1.4.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- postfix_network_listening_disabled
- restrict_strategy
- name: Make changes to Postfix configuration file
lineinfile:
path: /etc/postfix/main.cf
create: false
regexp: ^inet_interfaces\s*=\s.*
line: inet_interfaces = {{ var_postfix_inet_interfaces }}
state: present
insertafter: ^inet_interfaces\s*=\s.*
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"postfix" in ansible_facts.packages'
- '"postfix" in ansible_facts.packages'
tags:
- CCE-91280-8
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-1.4.2
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- postfix_network_listening_disabled
- restrict_strategy
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q postfix; }; then
var_postfix_inet_interfaces='loopback-only'
if [ -e "/etc/postfix/main.cf" ] ; then
LC_ALL=C sed -i "/^\s*inet_interfaces\s\+=\s\+/Id" "/etc/postfix/main.cf"
else
touch "/etc/postfix/main.cf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/postfix/main.cf"
cp "/etc/postfix/main.cf" "/etc/postfix/main.cf.bak"
# Insert at the end of the file
printf '%s\n' "inet_interfaces=$var_postfix_inet_interfaces" >> "/etc/postfix/main.cf"
# Clean up after ourselves.
rm "/etc/postfix/main.cf.bak"
systemctl restart postfix
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
NFS and RPC
[ref]groupThe Network File System is a popular distributed filesystem for
the Unix environment, and is very widely deployed. This section discusses the
circumstances under which it is possible to disable NFS and its dependencies,
and then details steps which should be taken to secure
NFS's configuration. This section is relevant to systems operating as NFS
clients, as well as to those operating as NFS servers. |
contains 1 rule |
Disable All NFS Services if Possible
[ref]groupIf there is not a reason for the system to operate as either an
NFS client or an NFS server, follow all instructions in this section to disable
subsystems required by NFS. Warning:
The steps in this section will prevent a system
from operating as either an NFS client or an NFS server. Only perform these
steps on systems which do not need NFS at all. |
contains 1 rule |
Disable Services Used Only by NFS
[ref]groupIf NFS is not needed, disable the NFS client daemons nfslock, rpcgssd, and rpcidmapd.
All of these daemons run with elevated privileges, and many listen for network
connections. If they are not needed, they should be disabled to improve system
security posture. |
contains 1 rule |
Disable rpcbind Service
[ref]ruleThe rpcbind utility maps RPC services to the ports on which they listen.
RPC processes notify rpcbind when they start, registering the ports they
are listening on and the RPC program numbers they expect to serve. The
rpcbind service redirects the client to the proper port number so it can
communicate with the requested service. If the system does not require RPC
(such as for NFS servers) then this service should be disabled.
The rpcbind service can be disabled with the following command:
$ sudo systemctl mask --now rpcbind.service Rationale:If the system does not require rpc based services, it is recommended that
rpcbind be disabled to reduce the attack surface. Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_rpcbind
class disable_rpcbind {
service {'rpcbind':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["rpcbind"]
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Block Disable service rpcbind
block:
- name: Disable service rpcbind
block:
- name: Disable service rpcbind
systemd:
name: rpcbind.service
enabled: 'no'
state: stopped
masked: 'yes'
rescue:
- name: Intentionally ignored previous 'Disable service rpcbind' failure, service
was already disabled
meta: noop
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91312-9
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_rpcbind_disabled
- name: Unit Socket Exists - rpcbind.socket
command: systemctl -q list-unit-files rpcbind.socket
register: socket_file_exists
changed_when: false
failed_when: socket_file_exists.rc not in [0, 1]
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91312-9
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_rpcbind_disabled
- name: Disable socket rpcbind
systemd:
name: rpcbind.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- socket_file_exists.stdout_lines is search("rpcbind.socket",multiline=True)
tags:
- CCE-91312-9
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- service_rpcbind_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'rpcbind.service'
"$SYSTEMCTL_EXEC" disable 'rpcbind.service'
"$SYSTEMCTL_EXEC" mask 'rpcbind.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files rpcbind.socket; then
"$SYSTEMCTL_EXEC" stop 'rpcbind.socket'
"$SYSTEMCTL_EXEC" mask 'rpcbind.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'rpcbind.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Network Time Protocol
[ref]groupThe Network Time Protocol is used to manage the system
clock over a network. Computer clocks are not very accurate, so
time will drift unpredictably on unmanaged systems. Central time
protocols can be used both to ensure that time is consistent among
a network of systems, and that their time is consistent with the
outside world.
If every system on a network reliably reports the same time, then it is much
easier to correlate log messages in case of an attack. In addition, a number of
cryptographic protocols (such as Kerberos) use timestamps to prevent certain
types of attacks. If your network does not have synchronized time, these
protocols may be unreliable or even unusable.
Depending on the specifics of the network, global time accuracy may be just as
important as local synchronization, or not very important at all. If your
network is connected to the Internet, using a public timeserver (or one
provided by your enterprise) provides globally accurate timestamps which may be
essential in investigating or responding to an attack which originated outside
of your network.
A typical network setup involves a small number of internal systems operating
as NTP servers, and the remainder obtaining time information from those
internal servers.
There is a choice between the daemons ntpd and chronyd , which
are available from the repositories in the ntp and chrony
packages respectively.
The default chronyd daemon can work well when external time references
are only intermittently accesible, can perform well even when the network is
congested for longer periods of time, can usually synchronize the clock faster
and with better time accuracy, and quickly adapts to sudden changes in the rate
of the clock, for example, due to changes in the temperature of the crystal
oscillator. Chronyd should be considered for all systems which are
frequently suspended or otherwise intermittently disconnected and reconnected
to a network. Mobile and virtual systems for example.
The ntpd NTP daemon fully supports NTP protocol version 4 (RFC 5905),
including broadcast, multicast, manycast clients and servers, and the orphan
mode. It also supports extra authentication schemes based on public-key
cryptography (RFC 5906). The NTP daemon (ntpd ) should be considered
for systems which are normally kept permanently on. Systems which are required
to use broadcast or multicast IP, or to perform authentication of packets with
the Autokey protocol, should consider using ntpd .
Refer to
https://docs.fedoraproject.org/en-US/fedora/latest/system-administrators-guide/servers/Configuring_NTP_Using_the_chrony_Suite/
for more detailed comparison of features of chronyd
and ntpd daemon features respectively, and for further guidance how to
choose between the two NTP daemons.
The upstream manual pages at
https://chrony-project.org/documentation.html for
chronyd and
http://www.ntp.org for ntpd provide additional
information on the capabilities and configuration of each of the NTP daemons. |
contains 4 rules |
The Chrony package is installed
[ref]ruleSystem time should be synchronized between all systems in an environment. This is
typically done by establishing an authoritative time server or set of servers and having all
systems synchronize their clocks to them.
The chrony package can be installed with the following command:
$ sudo zypper install chrony Rationale:Time synchronization is important to support time sensitive security mechanisms like
Kerberos and also ensures log files have consistent time records across the enterprise,
which aids in forensic investigations. Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include install_chrony
class install_chrony {
package { 'chrony':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "chrony"
version = "*"
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Ensure chrony is installed
package:
name: chrony
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91229-5
- PCI-DSS-Req-10.4
- PCI-DSSv4-10.6.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_chrony_installed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "chrony"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable the NTP Daemon
[ref]rule
Run the following command to determine the current status of the
chronyd service:
$ sudo systemctl is-active chronyd
If the service is running, it should return the following: active
Note: The chronyd daemon is enabled by default.
Run the following command to determine the current status of the
ntpd service:
$ sudo systemctl is-active ntpd
If the service is running, it should return the following: active
Note: The ntpd daemon is not enabled by default. Though as mentioned
in the previous sections in certain environments the ntpd daemon might
be preferred to be used rather than the chronyd one. Refer to:
https://documentation.suse.com/sles/15-SP1/html/SLES-all/cha-ntp.html
for guidance which NTP daemon to choose depending on the environment used.Rationale:Enabling some of chronyd or ntpd services ensures
that the NTP daemon will be running and that the system will synchronize its
time to any servers specified. This is important whether the system is
configured to be a client (and synchronize only its own clock) or it is also
acting as an NTP server to other systems. Synchronizing time is essential for
authentication services such as Kerberos, but it is also important for
maintaining accurate logs and auditing possible security breaches.
The chronyd and ntpd NTP daemons offer all of the
functionality of ntpdate , which is now deprecated. Identifiers:
CCE-85835-7 References:
BP28(R71), 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, 3.3.7, CCI-000160, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, 0988, 1405, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), AU-8(1)(a), AU-12(1), PR.PT-1, Req-10.4.1, 10.6.1, SRG-APP-000116-CTR-000235 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85835-7
- NIST-800-171-3.3.7
- NIST-800-53-AU-12(1)
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.1
- PCI-DSSv4-10.6.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_chronyd_or_ntpd_enabled
- name: Gather the package facts
ansible.builtin.package_facts:
manager: auto
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85835-7
- NIST-800-171-3.3.7
- NIST-800-53-AU-12(1)
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.1
- PCI-DSSv4-10.6.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_chronyd_or_ntpd_enabled
- name: Start ntpd service if ntp installed
systemd:
name: ntpd
enabled: 'yes'
state: started
masked: 'no'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '''ntp'' in ansible_facts.packages'
tags:
- CCE-85835-7
- NIST-800-171-3.3.7
- NIST-800-53-AU-12(1)
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.1
- PCI-DSSv4-10.6.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_chronyd_or_ntpd_enabled
- name: Start chronyd service if chrony or chronyd installed
systemd:
name: chronyd
enabled: 'yes'
state: started
masked: 'no'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ('chrony' in ansible_facts.packages) or ('chronyd' in ansible_facts.packages)
tags:
- CCE-85835-7
- NIST-800-171-3.3.7
- NIST-800-53-AU-12(1)
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.1
- PCI-DSSv4-10.6.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_chronyd_or_ntpd_enabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if rpm --quiet -q "chrony" ; then
if ! /usr/sbin/pidof ntpd ; then
/usr/bin/systemctl enable "chronyd"
/usr/bin/systemctl start "chronyd"
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
if /usr/bin/systemctl --failed | grep -q "chronyd"; then
/usr/bin/systemctl reset-failed "chronyd"
fi
fi
elif rpm --quiet -q "ntp" ; then
/usr/bin/systemctl enable "ntpd"
/usr/bin/systemctl start "ntpd"
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
if /usr/bin/systemctl --failed | grep -q "ntpd"; then
/usr/bin/systemctl reset-failed "ntpd"
fi
else
zypper install -y "chrony"
/usr/bin/systemctl enable "chronyd"
/usr/bin/systemctl start "chronyd"
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
if /usr/bin/systemctl --failed | grep -q "chronyd"; then
/usr/bin/systemctl reset-failed "chronyd"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure that chronyd is running under chrony user account
[ref]rulechrony is a daemon which implements the Network Time Protocol (NTP). It is designed to
synchronize system clocks across a variety of systems and use a source that is highly
accurate. More information on chrony can be found at
http://chrony.tuxfamily.org/.
Chrony can be configured to be a client and/or a server.
To ensure that chronyd is running under chrony user account,
add or edit the
OPTIONS variable in /etc/sysconfig/chronyd to include -u chrony :
OPTIONS="-u chrony"
This recommendation only applies if chrony is in use on the system.Rationale:If chrony is in use on the system proper configuration is vital to ensuring time synchronization
is working properly. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q chrony; }; then
if grep -q 'OPTIONS=.*' /etc/sysconfig/chronyd; then
# trying to solve cases where the parameter after OPTIONS
#may or may not be enclosed in quotes
sed -i -E -e 's/\s*-u\s*\w+\s*/ /' -e 's/^([\s]*OPTIONS=["]?[^"]*)("?)/\1 -u chrony\2/' /etc/sysconfig/chronyd
else
echo 'OPTIONS="-u chrony"' >> /etc/sysconfig/chronyd
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
A remote time server for Chrony is configured
[ref]ruleChrony is a daemon which implements the Network Time Protocol (NTP). It is designed to
synchronize system clocks across a variety of systems and use a source that is highly
accurate. More information on chrony can be found at
http://chrony.tuxfamily.org/.
Chrony can be configured to be a client and/or a server.
Add or edit server or pool lines to /etc/chrony.conf as appropriate:
server <remote-server>
Multiple servers may be configured.Rationale:If chrony is in use on the system proper configuration is vital to ensuring time
synchronization is working properly. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85833-2
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.3
- PCI-DSSv4-10.6.2
- chronyd_specify_remote_server
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: XCCDF Value var_multiple_time_servers # promote to variable
set_fact:
var_multiple_time_servers: !!str 0.suse.pool.ntp.org,1.suse.pool.ntp.org,2.suse.pool.ntp.org,3.suse.pool.ntp.org
tags:
- always
- name: Detect if chrony is already configured with pools or servers
find:
path: /etc
patterns: chrony.conf
contains: ^[\s]*(?:server|pool)[\s]+[\w]+
register: chrony_servers
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages'
tags:
- CCE-85833-2
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.3
- PCI-DSSv4-10.6.2
- chronyd_specify_remote_server
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Configure remote time servers
lineinfile:
path: /etc/chrony.conf
line: server {{ item }}
state: present
create: true
loop: '{{ var_multiple_time_servers.split(",") }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages'
- chrony_servers.matched == 0
tags:
- CCE-85833-2
- NIST-800-53-AU-8(1)(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.4.3
- PCI-DSSv4-10.6.2
- chronyd_specify_remote_server
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q chrony; }; then
var_multiple_time_servers='0.suse.pool.ntp.org,1.suse.pool.ntp.org,2.suse.pool.ntp.org,3.suse.pool.ntp.org'
config_file="/etc/chrony.conf"
if ! grep -q '^[[:space:]]*\(server\|pool\)[[:space:]]\+[[:graph:]]\+' "$config_file" ; then
if ! grep -q '#[[:space:]]*server' "$config_file" ; then
for server in $(echo "$var_multiple_time_servers" | tr ',' '\n') ; do
printf '\nserver %s' "$server" >> "$config_file"
done
else
sed -i 's/#[ \t]*server/server/g' "$config_file"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Obsolete Services
[ref]groupThis section discusses a number of network-visible
services which have historically caused problems for system
security, and for which disabling or severely limiting the service
has been the best available guidance for some time. As a result of
this, many of these services are not installed as part of SUSE Linux Enterprise 15
by default.
Organizations which are running these services should
switch to more secure equivalents as soon as possible.
If it remains absolutely necessary to run one of
these services for legacy reasons, care should be taken to restrict
the service as much as possible, for instance by configuring host
firewall software such as iptables to restrict access to the
vulnerable service to only those remote hosts which have a known
need to use it. |
contains 12 rules |
Xinetd
[ref]groupThe xinetd service acts as a dedicated listener for some
network services (mostly, obsolete ones) and can be used to provide access
controls and perform some logging. It has been largely obsoleted by other
features, and it is not installed by default. The older Inetd service
is not even available as part of SUSE Linux Enterprise 15. |
contains 1 rule |
Uninstall xinetd Package
[ref]ruleThe xinetd package can be removed with the following command:
$ sudo zypper remove xinetd Rationale:Removing the xinetd package decreases the risk of the
xinetd service's accidental (or intentional) activation. Identifiers:
CCE-91436-6 References:
BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000305, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, 2.2.4, 2.1.1 Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_xinetd
class remove_xinetd {
package { 'xinetd':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure xinetd is removed
package:
name: xinetd
state: absent
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91436-6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_xinetd_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# CAUTION: This remediation script will remove xinetd
# from the system, and may remove any packages
# that depend on xinetd. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "xinetd"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
The Network Information Service (NIS), also known as 'Yellow
Pages' (YP), and its successor NIS+ have been made obsolete by
Kerberos, LDAP, and other modern centralized authentication
services. NIS should not be used because it suffers from security
problems inherent in its design, such as inadequate protection of
important authentication information. |
contains 2 rules |
Remove NIS Client
[ref]ruleThe Network Information Service (NIS), formerly known as Yellow Pages,
is a client-server directory service protocol used to distribute system configuration
files. The NIS client (ypbind ) was used to bind a system to an NIS server
and receive the distributed configuration files. Rationale:The NIS service is inherently an insecure system that has been vulnerable
to DOS attacks, buffer overflows and has poor authentication for querying
NIS maps. NIS generally has been replaced by such protocols as Lightweight
Directory Access Protocol (LDAP). It is recommended that the service be
removed. Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_ypbind
class remove_ypbind {
package { 'ypbind':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure ypbind is removed
package:
name: ypbind
state: absent
tags:
- CCE-91159-4
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- package_ypbind_removed
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove ypbind
# from the system, and may remove any packages
# that depend on ypbind. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "ypbind"
|
Uninstall ypserv Package
[ref]ruleThe ypserv package can be removed with the following command:
$ sudo zypper remove ypserv Rationale:The NIS service provides an unencrypted authentication service which does
not provide for the confidentiality and integrity of user passwords or the
remote session.
Removing the ypserv package decreases the risk of the accidental
(or intentional) activation of NIS or NIS+ services. Identifiers:
CCE-91160-2 References:
BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, Req-2.2.2, 2.2.4, SRG-OS-000095-GPOS-00049, 2.2.18 Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_ypserv
class remove_ypserv {
package { 'ypserv':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure ypserv is removed
package:
name: ypserv
state: absent
tags:
- CCE-91160-2
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-IA-5(1)(c)
- PCI-DSS-Req-2.2.2
- PCI-DSSv4-2.2.4
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- package_ypserv_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove ypserv
# from the system, and may remove any packages
# that depend on ypserv. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "ypserv"
|
Rlogin, Rsh, and Rexec
[ref]groupThe Berkeley r-commands are legacy services which
allow cleartext remote access and have an insecure trust
model. |
contains 2 rules |
Uninstall rsh-server Package
[ref]ruleThe rsh-server package can be removed with the following command:
$ sudo zypper remove rsh-server Rationale:The rsh-server service provides unencrypted remote access service which does not
provide for the confidentiality and integrity of user passwords or the remote session and has very weak
authentication. If a privileged user were to login using this service, the privileged user password
could be compromised. The rsh-server package provides several obsolete and insecure
network services. Removing it decreases the risk of those services' accidental (or intentional)
activation. Identifiers:
CCE-91425-9 References:
BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, 2.2.4, SRG-OS-000095-GPOS-00049 Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_rsh-server
class remove_rsh-server {
package { 'rsh-server':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure rsh-server is removed
package:
name: rsh-server
state: absent
tags:
- CCE-91425-9
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-IA-5(1)(c)
- PCI-DSSv4-2.2.4
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- package_rsh-server_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove rsh-server
# from the system, and may remove any packages
# that depend on rsh-server. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "rsh-server"
|
Uninstall rsh Package
[ref]rule
The rsh package contains the client commands
for the rsh services Rationale:These legacy clients contain numerous security exposures and have
been replaced with the more secure SSH package. Even if the server is removed,
it is best to ensure the clients are also removed to prevent users from
inadvertently attempting to use these commands and therefore exposing
their credentials. Note that removing the rsh package removes
the clients for rsh ,rcp , and rlogin . Identifiers:
CCE-85760-7 References:
BP28(R1), 3.1.13, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), A.8.2.3, A.13.1.1, A.13.2.1, A.13.2.3, A.14.1.2, A.14.1.3, 2.2.4, 2.3.2 Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_rsh
class remove_rsh {
package { 'rsh':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure rsh is removed
package:
name: rsh
state: absent
tags:
- CCE-85760-7
- NIST-800-171-3.1.13
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- package_rsh_removed
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove rsh
# from the system, and may remove any packages
# that depend on rsh. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "rsh"
|
Chat/Messaging Services
[ref]groupThe talk software makes it possible for users to send and receive messages
across systems through a terminal session. |
contains 2 rules |
Uninstall talk-server Package
[ref]ruleThe talk-server package can be removed with the following command: $ sudo zypper remove talk-server Rationale:The talk software presents a security risk as it uses unencrypted protocols
for communications. Removing the talk-server package decreases the
risk of the accidental (or intentional) activation of talk services. Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_talk-server
class remove_talk-server {
package { 'talk-server':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure talk-server is removed
package:
name: talk-server
state: absent
tags:
- CCE-91433-3
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_talk-server_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove talk-server
# from the system, and may remove any packages
# that depend on talk-server. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "talk-server"
|
Uninstall talk Package
[ref]ruleThe talk package contains the client program for the
Internet talk protocol, which allows the user to chat with other users on
different systems. Talk is a communication program which copies lines from one
terminal to the terminal of another user.
The talk package can be removed with the following command:
$ sudo zypper remove talk Rationale:The talk software presents a security risk as it uses unencrypted protocols
for communications. Removing the talk package decreases the
risk of the accidental (or intentional) activation of talk client program. Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_talk
class remove_talk {
package { 'talk':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure talk is removed
package:
name: talk
state: absent
tags:
- CCE-91432-5
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_talk_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove talk
# from the system, and may remove any packages
# that depend on talk. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "talk"
|
Telnet
[ref]groupThe telnet protocol does not provide confidentiality or integrity
for information transmitted on the network. This includes authentication
information such as passwords. Organizations which use telnet should be
actively working to migrate to a more secure protocol. |
contains 2 rules |
Uninstall telnet-server Package
[ref]ruleThe telnet-server package can be removed with the following command:
$ sudo zypper remove telnet-server Rationale:It is detrimental for operating systems to provide, or install by default,
functionality exceeding requirements or mission objectives. These
unnecessary capabilities are often overlooked and therefore may remain
unsecure. They increase the risk to the platform by providing additional
attack vectors.
The telnet service provides an unencrypted remote access service which does
not provide for the confidentiality and integrity of user passwords or the
remote session. If a privileged user were to login using this service, the
privileged user password could be compromised.
Removing the telnet-server package decreases the risk of the
telnet service's accidental (or intentional) activation. Identifiers:
CCE-83273-3 References:
BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, Req-2.2.2, 2.2.4, SRG-OS-000095-GPOS-00049, SLES-15-010180, 2.2.19, SV-234818r877396_rule Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_telnet-server
class remove_telnet-server {
package { 'telnet-server':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure telnet-server is removed
package:
name: telnet-server
state: absent
tags:
- CCE-83273-3
- DISA-STIG-SLES-15-010180
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSS-Req-2.2.2
- PCI-DSSv4-2.2.4
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- package_telnet-server_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove telnet-server
# from the system, and may remove any packages
# that depend on telnet-server. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "telnet-server"
|
Remove telnet Clients
[ref]ruleThe telnet client allows users to start connections to other systems via
the telnet protocol. Rationale:The telnet protocol is insecure and unencrypted. The use
of an unencrypted transmission medium could allow an unauthorized user
to steal credentials. The ssh package provides an
encrypted session and stronger security and is included in SUSE Linux Enterprise 15. Identifiers:
CCE-91434-1 References:
BP28(R1), 3.1.13, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), A.8.2.3, A.13.1.1, A.13.2.1, A.13.2.3, A.14.1.2, A.14.1.3, 2.2.4, 2.3.4 Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_telnet
class remove_telnet {
package { 'telnet':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure telnet is removed
package:
name: telnet
state: absent
tags:
- CCE-91434-1
- NIST-800-171-3.1.13
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_telnet_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove telnet
# from the system, and may remove any packages
# that depend on telnet. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "telnet"
|
TFTP Server
[ref]groupTFTP is a lightweight version of the FTP protocol which has
traditionally been used to configure networking equipment. However,
TFTP provides little security, and modern versions of networking
operating systems frequently support configuration via SSH or other
more secure protocols. A TFTP server should be run only if no more
secure method of supporting existing equipment can be
found. |
contains 2 rules |
Uninstall tftp-server Package
[ref]ruleThe tftp-server package can be removed with the following command: $ sudo zypper remove tftp-server Rationale:Removing the tftp-server package decreases the risk of the accidental
(or intentional) activation of tftp services.
If TFTP is required for operational support (such as transmission of router
configurations), its use must be documented with the Information Systems
Securty Manager (ISSM), restricted to only authorized personnel, and have
access control rules established. Identifiers:
CCE-91227-9 References:
BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000318, CCI-000366, CCI-000368, CCI-001812, CCI-001813, CCI-001814, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, 2.2.4, SRG-OS-000480-GPOS-00227 Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_tftp-server
class remove_tftp-server {
package { 'tftp-server':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure tftp-server is removed
package:
name: tftp-server
state: absent
tags:
- CCE-91227-9
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-2.2.4
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- package_tftp-server_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove tftp-server
# from the system, and may remove any packages
# that depend on tftp-server. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "tftp-server"
|
Remove tftp Daemon
[ref]ruleTrivial File Transfer Protocol (TFTP) is a simple file transfer protocol,
typically used to automatically transfer configuration or boot files between systems.
TFTP does not support authentication and can be easily hacked. The package
tftp is a client program that allows for connections to a tftp server. Rationale:It is recommended that TFTP be removed, unless there is a specific need
for TFTP (such as a boot server). In that case, use extreme caution when configuring
the services. Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_tftp
class remove_tftp {
package { 'tftp':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure tftp is removed
package:
name: tftp
state: absent
tags:
- CCE-91158-6
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- package_tftp_removed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove tftp
# from the system, and may remove any packages
# that depend on tftp. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "tftp"
|
Ensure rsyncd service is disabled
[ref]rule
The rsyncd service can be disabled with the following command:
$ sudo systemctl mask --now rsyncd.service Rationale:The rsyncd service presents a security risk as it uses unencrypted protocols for
communication. Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | enable |
---|
include disable_rsyncd
class disable_rsyncd {
service {'rsyncd':
enable => false,
ensure => 'stopped',
}
}
Remediation script: (show)
[customizations.services]
disabled = ["rsyncd"]
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Block Disable service rsyncd
block:
- name: Disable service rsyncd
block:
- name: Disable service rsyncd
systemd:
name: rsyncd.service
enabled: 'no'
state: stopped
masked: 'yes'
rescue:
- name: Intentionally ignored previous 'Disable service rsyncd' failure, service
was already disabled
meta: noop
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91305-3
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_rsyncd_disabled
- name: Unit Socket Exists - rsyncd.socket
command: systemctl -q list-unit-files rsyncd.socket
register: socket_file_exists
changed_when: false
failed_when: socket_file_exists.rc not in [0, 1]
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91305-3
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_rsyncd_disabled
- name: Disable socket rsyncd
systemd:
name: rsyncd.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- socket_file_exists.stdout_lines is search("rsyncd.socket",multiline=True)
tags:
- CCE-91305-3
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_rsyncd_disabled
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'rsyncd.service'
"$SYSTEMCTL_EXEC" disable 'rsyncd.service'
"$SYSTEMCTL_EXEC" mask 'rsyncd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files rsyncd.socket; then
"$SYSTEMCTL_EXEC" stop 'rsyncd.socket'
"$SYSTEMCTL_EXEC" mask 'rsyncd.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'rsyncd.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
SNMP Server
[ref]groupThe Simple Network Management Protocol allows
administrators to monitor the state of network devices, including
computers. Older versions of SNMP were well-known for weak
security, such as plaintext transmission of the community string
(used for authentication) and usage of easily-guessable
choices for the community string. |
contains 1 rule |
Disable SNMP Server if Possible
[ref]groupThe system includes an SNMP daemon that allows for its remote
monitoring, though it not installed by default. If it was installed and
activated but is not needed, the software should be disabled and removed. |
contains 1 rule |
Uninstall net-snmp Package
[ref]rule
The net-snmp package provides the snmpd service.
The net-snmp package can be removed with the following command:
$ sudo zypper remove net-snmp Rationale:If there is no need to run SNMP server software,
removing the package provides a safeguard against its
activation. Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
include remove_net-snmp
class remove_net-snmp {
package { 'net-snmp':
ensure => 'purged',
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
- name: Ensure net-snmp is removed
package:
name: net-snmp
state: absent
tags:
- CCE-91288-1
- PCI-DSSv4-2.2.4
- disable_strategy
- low_complexity
- low_disruption
- no_reboot_needed
- package_net-snmp_removed
- unknown_severity
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove net-snmp
# from the system, and may remove any packages
# that depend on net-snmp. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "net-snmp"
|
SSH Server
[ref]groupThe SSH protocol is recommended for remote login and
remote file transfer. SSH provides confidentiality and integrity
for data exchanged between two systems, as well as server
authentication, through the use of public key cryptography. The
implementation included with the system is called OpenSSH, and more
detailed documentation is available from its website,
https://www.openssh.com.
Its server program is called sshd and provided by the RPM package
openssh-server . |
contains 22 rules |
Configure OpenSSH Server if Necessary
[ref]groupIf the system needs to act as an SSH server, then
certain changes should be made to the OpenSSH daemon configuration
file /etc/ssh/sshd_config . The following recommendations can be
applied to this file. See the sshd_config(5) man page for more
detailed information. |
contains 19 rules |
Set SSH Client Alive Count Max
[ref]ruleThe SSH server sends at most ClientAliveCountMax messages
during a SSH session and waits for a response from the SSH client.
The option ClientAliveInterval configures timeout after
each ClientAliveCountMax message. If the SSH server does not
receive a response from the client, then the connection is considered unresponsive
and terminated.
For SSH earlier than v8.2, a ClientAliveCountMax value of 0
causes a timeout precisely when the ClientAliveInterval is set.
Starting with v8.2, a value of 0 disables the timeout functionality
completely. If the option is set to a number greater than 0 , then
the session will be disconnected after
ClientAliveInterval * ClientAliveCountMax seconds without receiving
a keep alive message. Rationale:This ensures a user login will be terminated as soon as the ClientAliveInterval
is reached. Identifiers:
CCE-91228-7 References:
BP28(R32), 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, Req-8.1.8, 8.2.8, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, SLES-15-010320, 5.2.16, SV-234830r854190_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_sshd_set_keepalive # promote to variable
set_fact:
var_sshd_set_keepalive: !!str 0
tags:
- always
- name: Set SSH Client Alive Count Max
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*ClientAliveCountMax\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*ClientAliveCountMax\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*ClientAliveCountMax\s+
line: ClientAliveCountMax {{ var_sshd_set_keepalive }}
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91228-7
- CJIS-5.5.6
- DISA-STIG-SLES-15-010320
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_keepalive
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_sshd_set_keepalive='0'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*ClientAliveCountMax\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "ClientAliveCountMax $var_sshd_set_keepalive" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set SSH Client Alive Interval
[ref]ruleSSH allows administrators to set a network responsiveness timeout interval.
After this interval has passed, the unresponsive client will be automatically logged out.
To set this timeout interval, edit the following line in /etc/ssh/sshd_config as
follows:
ClientAliveInterval 900
The timeout interval is given in seconds. For example, have a timeout
of 10 minutes, set interval to 600.
If a shorter timeout has already been set for the login shell, that value will
preempt any SSH setting made in /etc/ssh/sshd_config . Keep in mind that
some processes may stop SSH from correctly detecting that the user is idle.Warning:
SSH disconnecting unresponsive clients will not have desired effect without also
configuring ClientAliveCountMax in the SSH service configuration. Warning:
Following conditions may prevent the SSH session to time out:
- Remote processes on the remote machine generates output. As the output has to be transferred over the network to the client, the timeout is reset every time such transfer happens.
- Any
scp or sftp activity by the same user to the host resets the timeout.
Rationale:Terminating an idle ssh session within a short time period reduces the window of
opportunity for unauthorized personnel to take control of a management session
enabled on the console or console port that has been let unattended. Identifiers:
CCE-83281-6 References:
BP28(R29), 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CM-6(a), AC-17(a), AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, Req-8.1.8, 8.2.8, SRG-OS-000126-GPOS-00066, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, SRG-OS-000395-GPOS-00175, SLES-15-010280, 5.2.16, SV-234827r854189_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value sshd_idle_timeout_value # promote to variable
set_fact:
sshd_idle_timeout_value: !!str 900
tags:
- always
- name: Set SSH Client Alive Interval
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*ClientAliveInterval\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*ClientAliveInterval\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*ClientAliveInterval\s+
line: ClientAliveInterval {{ sshd_idle_timeout_value }}
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83281-6
- CJIS-5.5.6
- DISA-STIG-SLES-15-010280
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSS-Req-8.1.8
- PCI-DSSv4-8.2.8
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_idle_timeout
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
sshd_idle_timeout_value='900'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*ClientAliveInterval\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "ClientAliveInterval $sshd_idle_timeout_value" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable Host-Based Authentication
[ref]ruleSSH's cryptographic host-based authentication is
more secure than .rhosts authentication. However, it is
not recommended that hosts unilaterally trust one another, even
within an organization.
The default SSH configuration disables host-based authentication. The appropriate
configuration is used if no value is set for HostbasedAuthentication .
To explicitly disable host-based authentication, add or correct the
following line in
/etc/ssh/sshd_config :
HostbasedAuthentication no Rationale:SSH trust relationships mean a compromise on one host
can allow an attacker to move trivially to other hosts. Identifiers:
CCE-91439-0 References:
11, 12, 14, 15, 16, 18, 3, 5, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-3, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.IP-1, PR.PT-3, FIA_UAU.1, 8.3.1, SRG-OS-000480-GPOS-00229, 5.2.9 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable Host-Based Authentication
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*HostbasedAuthentication\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*HostbasedAuthentication\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*HostbasedAuthentication\s+
line: HostbasedAuthentication no
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91439-0
- CJIS-5.5.6
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-3
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-8.3.1
- disable_host_auth
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*HostbasedAuthentication\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "HostbasedAuthentication no" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable SSH Access via Empty Passwords
[ref]ruleDisallow SSH login with empty passwords.
The default SSH configuration disables logins with empty passwords. The appropriate
configuration is used if no value is set for PermitEmptyPasswords .
To explicitly disallow SSH login from accounts with empty passwords,
add or correct the following line in
/etc/ssh/sshd_config :
PermitEmptyPasswords no
Any accounts with empty passwords should be disabled immediately, and PAM configuration
should prevent users from being able to assign themselves empty passwords.Rationale:Configuring this setting for the SSH daemon provides additional assurance
that remote login via SSH will require a password, even in the event of
misconfiguration elsewhere. Identifiers:
CCE-85667-4 References:
NT007(R17), 11, 12, 13, 14, 15, 16, 18, 3, 5, 9, 5.5.6, APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, 3.1.1, 3.1.5, CCI-000366, CCI-000766, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(b), CM-6.1(iv), PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3, FIA_UAU.1, Req-2.2.4, 2.2.6, SRG-OS-000106-GPOS-00053, SRG-OS-000480-GPOS-00229, SRG-OS-000480-GPOS-00227, SLES-15-040440, 5.2.11, SV-235032r877377_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable SSH Access via Empty Passwords
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitEmptyPasswords\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitEmptyPasswords\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitEmptyPasswords\s+
line: PermitEmptyPasswords no
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85667-4
- CJIS-5.5.6
- DISA-STIG-SLES-15-040440
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
- sshd_disable_empty_passwords
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*PermitEmptyPasswords\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "PermitEmptyPasswords no" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable SSH Support for .rhosts Files
[ref]ruleSSH can emulate the behavior of the obsolete rsh
command in allowing users to enable insecure access to their
accounts via .rhosts files.
The default SSH configuration disables support for .rhosts . The appropriate
configuration is used if no value is set for IgnoreRhosts .
To explicitly disable support for .rhosts files, add or correct the following line in
/etc/ssh/sshd_config :
IgnoreRhosts yes Rationale:SSH trust relationships mean a compromise on one host
can allow an attacker to move trivially to other hosts. Identifiers:
CCE-91307-9 References:
11, 12, 14, 15, 16, 18, 3, 5, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.1.12, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.IP-1, PR.PT-3, FIA_UAU.1, 2.2.6, SRG-OS-000480-GPOS-00227, 5.2.8 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable SSH Support for .rhosts Files
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*IgnoreRhosts\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*IgnoreRhosts\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*IgnoreRhosts\s+
line: IgnoreRhosts yes
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91307-9
- CJIS-5.5.6
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_rhosts
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*IgnoreRhosts\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "IgnoreRhosts yes" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable SSH Root Login
[ref]ruleThe root user should never be allowed to login to a
system directly over a network.
To disable root login via SSH, add or correct the following line in
/etc/ssh/sshd_config :
PermitRootLogin no Rationale:Even though the communications channel may be encrypted, an additional layer of
security is gained by extending the policy of not logging directly on as root.
In addition, logging in with a user-specific account provides individual
accountability of actions performed on the system and also helps to minimize
direct attack attempts on root's password. Identifiers:
CCE-85557-7 References:
BP28(R19), NT007(R21), 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.6, APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10, 3.1.1, 3.1.5, CCI-000366, CCI-000770, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-6(2), AC-17(a), IA-2, IA-2(5), CM-7(a), CM-7(b), CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3, FAU_GEN.1, Req-2.2.4, 2.2.6, SRG-OS-000109-GPOS-00056, SRG-OS-000480-GPOS-00227, SRG-APP-000148-CTR-000335, SRG-APP-000190-CTR-000500, SLES-15-020040, 5.2.10, SV-234870r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable SSH Root Login
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitRootLogin\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitRootLogin\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitRootLogin\s+
line: PermitRootLogin no
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85557-7
- CJIS-5.5.6
- DISA-STIG-SLES-15-020040
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(2)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-IA-2
- NIST-800-53-IA-2(5)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_root_login
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*PermitRootLogin\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "PermitRootLogin no" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable SSH TCP Forwarding
[ref]ruleThe AllowTcpForwarding parameter specifies whether TCP forwarding is permitted.
To disable TCP forwarding, add or correct the following line in
/etc/ssh/sshd_config :
AllowTcpForwarding no Rationale:Leaving port forwarding enabled can expose the organization to security risks and back-doors. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable SSH TCP Forwarding
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*AllowTcpForwarding\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*AllowTcpForwarding\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*AllowTcpForwarding\s+
line: AllowTcpForwarding no
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91334-3
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_tcp_forwarding
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*AllowTcpForwarding\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "AllowTcpForwarding no" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Disable X11 Forwarding
[ref]ruleThe X11Forwarding parameter provides the ability to tunnel X11 traffic
through the connection to enable remote graphic connections.
SSH has the capability to encrypt remote X11 connections when SSH's
X11Forwarding option is enabled.
The default SSH configuration disables X11Forwarding. The appropriate
configuration is used if no value is set for X11Forwarding .
To explicitly disable X11 Forwarding, add or correct the following line in
/etc/ssh/sshd_config :
X11Forwarding no Rationale:Disable X11 forwarding unless there is an operational requirement to use X11
applications directly. There is a small risk that the remote X11 servers of
users who are logged in via SSH with X11 forwarding could be compromised by
other users on the X11 server. Note that even if X11 forwarding is disabled,
users can always install their own forwarders. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Disable X11 Forwarding
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*X11Forwarding\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*X11Forwarding\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*X11Forwarding\s+
line: X11Forwarding no
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85707-8
- DISA-STIG-SLES-15-040290
- NIST-800-53-CM-6.1(iv)
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_x11_forwarding
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*X11Forwarding\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "X11Forwarding no" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Do Not Allow SSH Environment Options
[ref]ruleEnsure that users are not able to override environment variables of the SSH daemon.
The default SSH configuration disables environment processing. The appropriate
configuration is used if no value is set for PermitUserEnvironment .
To explicitly disable Environment options, add or correct the following
/etc/ssh/sshd_config :
PermitUserEnvironment no Rationale:SSH environment options potentially allow users to bypass
access restriction in some configurations. Identifiers:
CCE-85666-6 References:
11, 3, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-6(b), CM-6.1(iv), PR.IP-1, Req-2.2.4, 2.2.6, SRG-OS-000480-GPOS-00229, SLES-15-040440, 5.2.12, SV-235032r877377_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Do Not Allow SSH Environment Options
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitUserEnvironment\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitUserEnvironment\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitUserEnvironment\s+
line: PermitUserEnvironment no
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85666-6
- CJIS-5.5.6
- DISA-STIG-SLES-15-040440
- NIST-800-171-3.1.12
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_do_not_permit_user_env
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*PermitUserEnvironment\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "PermitUserEnvironment no" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Enable PAM
[ref]ruleUsePAM Enables the Pluggable Authentication Module interface. If set to “yes” this will
enable PAM authentication using ChallengeResponseAuthentication and
PasswordAuthentication in addition to PAM account and session module processing for all
authentication types.
To enable PAM authentication, add or correct the following line in
/etc/ssh/sshd_config :
UsePAM yes Rationale:When UsePAM is set to yes, PAM runs through account and session types properly. This is
important if you want to restrict access to services based off of IP, time or other factors of
the account. Additionally, you can make sure users inherit certain environment variables
on login or disallow access to the server. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Enable PAM
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*UsePAM\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*UsePAM\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*UsePAM\s+
line: UsePAM yes
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91333-5
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_enable_pam
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*UsePAM\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "UsePAM yes" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Limit Users' SSH Access
[ref]ruleBy default, the SSH configuration allows any user with an account
to access the system. There are several options available to limit
which users and group can access the system via SSH. It is
recommended that at least one of the following options be leveraged:
- AllowUsers variable gives the system administrator the option of
allowing specific users to ssh into the system. The list consists of
space separated user names. Numeric user IDs are not recognized with
this variable. If a system administrator wants to restrict user
access further by specifically allowing a user's access only from a
particular host, the entry can be specified in the form of user@host.
- AllowGroups variable gives the system administrator the option of
allowing specific groups of users to ssh into the system. The list
consists of space separated group names. Numeric group IDs are not
recognized with this variable.
- DenyUsers variable gives the system administrator the option of
denying specific users to ssh into the system. The list consists of
space separated user names. Numeric user IDs are not recognized with
this variable. If a system administrator wants to restrict user
access further by specifically denying a user's access from a
particular host, the entry can be specified in the form of user@host.
- DenyGroups variable gives the system administrator the option of
denying specific groups of users to ssh into the system. The list
consists of space separated group names. Numeric group IDs are not
recognized with this variable. Rationale:Specifying which accounts are allowed SSH access into the system reduces the
possibility of unauthorized access to the system. Identifiers:
CCE-91343-4 References:
11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.1.12, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-3, CM-6(a), PR.AC-4, PR.AC-6, PR.PT-3, Req-2.2.4, 2.2.6, 5.2.4 |
Ensure SSH LoginGraceTime is configured
[ref]ruleThe LoginGraceTime parameter to the SSH server specifies the time allowed for successful authentication to
the SSH server. The longer the Grace period is the more open unauthenticated connections
can exist. Like other session controls in this session the Grace Period should be limited to
appropriate limits to ensure the service is available for needed access. Rationale:Setting the LoginGraceTime parameter to a low number will minimize the risk of successful
brute force attacks to the SSH server. It will also limit the number of concurrent
unauthenticated connections. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_sshd_set_login_grace_time # promote to variable
set_fact:
var_sshd_set_login_grace_time: !!str 60
tags:
- always
- name: Ensure SSH LoginGraceTime is configured
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*LoginGraceTime\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*LoginGraceTime\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*LoginGraceTime\s+
line: LoginGraceTime {{ var_sshd_set_login_grace_time }}
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91397-0
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_login_grace_time
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_sshd_set_login_grace_time='60'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*LoginGraceTime\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "LoginGraceTime $var_sshd_set_login_grace_time" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set SSH Daemon LogLevel to VERBOSE
[ref]ruleThe VERBOSE parameter configures the SSH daemon to record login and logout activity.
To specify the log level in
SSH, add or correct the following line in
/etc/ssh/sshd_config :
LogLevel VERBOSE Rationale:SSH provides several logging levels with varying amounts of verbosity. DEBUG is specifically
not recommended other than strictly for debugging SSH communications since it provides
so much data that it is difficult to identify important security information. INFO or
VERBOSE level is the basic level that only records login activity of SSH users. In many
situations, such as Incident Response, it is important to determine when a particular user was active
on a system. The logout record can eliminate those users who disconnected, which helps narrow the
field. Identifiers:
CCE-83270-9 References:
CCI-000067, CIP-007-3 R7.1, AC-17(a), AC-17(1), CM-6(a), Req-2.2.4, 2.2.6, SRG-OS-000032-GPOS-00013, SLES-15-010150, 5.2.5, SV-234815r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: Set SSH Daemon LogLevel to VERBOSE
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*LogLevel\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*LogLevel\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*LogLevel\s+
line: LogLevel VERBOSE
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83270-9
- DISA-STIG-SLES-15-010150
- NIST-800-53-AC-17(1)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_loglevel_verbose
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*LogLevel\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "LogLevel VERBOSE" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set SSH authentication attempt limit
[ref]ruleThe MaxAuthTries parameter specifies the maximum number of authentication attempts
permitted per connection. Once the number of failures reaches half this value, additional failures are logged.
to set MaxAUthTries edit /etc/ssh/sshd_config as follows:
MaxAuthTries 4 Rationale:Setting the MaxAuthTries parameter to a low number will minimize the risk of successful
brute force attacks to the SSH server. Identifiers:
CCE-91332-7 References:
0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, 2.2.6, 5.2.7 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value sshd_max_auth_tries_value # promote to variable
set_fact:
sshd_max_auth_tries_value: !!str 4
tags:
- always
- name: Set SSH authentication attempt limit
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxAuthTries\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxAuthTries\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxAuthTries\s+
line: MaxAuthTries {{ sshd_max_auth_tries_value }}
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91332-7
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_max_auth_tries
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
sshd_max_auth_tries_value='4'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*MaxAuthTries\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "MaxAuthTries $sshd_max_auth_tries_value" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Set SSH MaxSessions limit
[ref]ruleThe MaxSessions parameter specifies the maximum number of open sessions permitted
from a given connection. To set MaxSessions edit
/etc/ssh/sshd_config as follows: MaxSessions 10 Rationale:To protect a system from denial of service due to a large number of concurrent
sessions, use the rate limiting function of MaxSessions to protect availability
of sshd logins and prevent overwhelming the daemon. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: XCCDF Value var_sshd_max_sessions # promote to variable
set_fact:
var_sshd_max_sessions: !!str 10
tags:
- always
- name: Set SSH MaxSessions limit
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxSessions\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxSessions\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxSessions\s+
line: MaxSessions {{ var_sshd_max_sessions }}
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91309-5
- PCI-DSSv4-2.2.6
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- sshd_set_max_sessions
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_sshd_max_sessions='10'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*MaxSessions\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "MaxSessions $var_sshd_max_sessions" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure SSH MaxStartups is configured
[ref]ruleThe MaxStartups parameter specifies the maximum number of concurrent
unauthenticated connections to the SSH daemon. Additional connections will be
dropped until authentication succeeds or the LoginGraceTime expires for a
connection. To confgure MaxStartups, you should add or correct the following
line in the
/etc/ssh/sshd_config file:
MaxStartups 10:30:100
CIS recommends a MaxStartups value of '10:30:60', or more restrictive where
dictated by site policy.Rationale:To protect a system from denial of service due to a large number of pending
authentication connection attempts, use the rate limiting function of MaxStartups
to protect availability of sshd logins and prevent overwhelming the daemon. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_sshd_set_maxstartups # promote to variable
set_fact:
var_sshd_set_maxstartups: !!str 10:30:100
tags:
- always
- name: Ensure SSH MaxStartups is configured
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxStartups\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxStartups\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MaxStartups\s+
line: MaxStartups {{ var_sshd_set_maxstartups }}
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91308-7
- PCI-DSSv4-2.2.6
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_maxstartups
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_sshd_set_maxstartups='10:30:100'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*MaxStartups\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "MaxStartups $var_sshd_set_maxstartups" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Use Only FIPS 140-2 Validated Ciphers
[ref]ruleLimit the ciphers to those algorithms which are FIPS-approved.
Counter (CTR) mode is also preferred over cipher-block chaining (CBC) mode.
The following line in /etc/ssh/sshd_config
demonstrates use of FIPS-approved ciphers:
Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc
The man page sshd_config(5) contains a list of supported ciphers.
The rule is parametrized to use the following ciphers: chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr .Warning:
The system needs to be rebooted for these changes to take effect. Warning:
System Crypto Modules must be provided by a vendor that undergoes
FIPS-140 certifications.
FIPS-140 is applicable to all Federal agencies that use
cryptographic-based security systems to protect sensitive information
in computer and telecommunication systems (including voice systems) as
defined in Section 5131 of the Information Technology Management Reform
Act of 1996, Public Law 104-106. This standard shall be used in
designing and implementing cryptographic modules that Federal
departments and agencies operate or are operated for them under
contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf
To meet this, the system has to have cryptographic software provided by
a vendor that has undergone this certification. This means providing
documentation, test results, design information, and independent third
party review by an accredited lab. While open source software is
capable of meeting this, it does not meet FIPS-140 unless the vendor
submits to this process. Rationale:Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore
cannot be relied upon to provide confidentiality or integrity, and system data may be compromised.
Operating systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to
cryptographic modules.
FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules
utilize authentication that meets industry and government requirements. For government systems, this allows
Security Levels 1, 2, 3, or 4 for use on SUSE Linux Enterprise 15. Identifiers:
CCE-91337-6 References:
1, 11, 12, 14, 15, 16, 18, 3, 5, 6, 8, 9, 5.5.6, APO11.04, APO13.01, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, MEA02.01, 3.1.13, 3.13.11, 3.13.8, CCI-000068, CCI-000366, CCI-000803, CCI-000877, CCI-002890, CCI-003123, 164.308(b)(1), 164.308(b)(2), 164.312(e)(1), 164.312(e)(2)(i), 164.312(e)(2)(ii), 164.314(b)(2)(i), 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-6(a), AC-17(a), AC-17(2), SC-13, MA-4(6), IA-5(1)(c), SC-12(2), SC-12(3), PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-1, PR.PT-1, PR.PT-3, PR.PT-4, 2.2.7, SRG-OS-000033-GPOS-00014, SRG-OS-000120-GPOS-00061, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SLES-15-010160, 5.2.13, SV-234816r877398_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value sshd_approved_ciphers # promote to variable
set_fact:
sshd_approved_ciphers: !!str chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr
tags:
- always
- name: Use Only FIPS 140-2 Validated Ciphers
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*Ciphers\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*Ciphers\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*Ciphers\s+
line: Ciphers {{ sshd_approved_ciphers }}
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91337-6
- CJIS-5.5.6
- DISA-STIG-SLES-15-010160
- NIST-800-171-3.1.13
- NIST-800-171-3.13.11
- NIST-800-171-3.13.8
- NIST-800-53-AC-17(2)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-MA-4(6)
- NIST-800-53-SC-12(2)
- NIST-800-53-SC-12(3)
- NIST-800-53-SC-13
- PCI-DSSv4-2.2.7
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_use_approved_ciphers
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
sshd_approved_ciphers='chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr'
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^Ciphers")
# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "$sshd_approved_ciphers"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^Ciphers\\>" "/etc/ssh/sshd_config"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^Ciphers\\>.*/$escaped_formatted_output/gi" "/etc/ssh/sshd_config"
else
if [[ -s "/etc/ssh/sshd_config" ]] && [[ -n "$(tail -c 1 -- "/etc/ssh/sshd_config" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/ssh/sshd_config"
fi
cce="CCE-91337-6"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "/etc/ssh/sshd_config" >> "/etc/ssh/sshd_config"
printf '%s\n' "$formatted_output" >> "/etc/ssh/sshd_config"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Use Only FIPS 140-2 Validated MACs
[ref]ruleLimit the MACs to those hash algorithms which are FIPS-approved.
The following line in /etc/ssh/sshd_config
demonstrates use of FIPS-approved MACs:
MACs hmac-sha2-512,hmac-sha2-256
The man page sshd_config(5) contains a list of supported MACs.
The rule is parametrized to use the following MACs: hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256 .Warning:
The system needs to be rebooted for these changes to take effect. Warning:
System Crypto Modules must be provided by a vendor that undergoes
FIPS-140 certifications.
FIPS-140 is applicable to all Federal agencies that use
cryptographic-based security systems to protect sensitive information
in computer and telecommunication systems (including voice systems) as
defined in Section 5131 of the Information Technology Management Reform
Act of 1996, Public Law 104-106. This standard shall be used in
designing and implementing cryptographic modules that Federal
departments and agencies operate or are operated for them under
contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf
To meet this, the system has to have cryptographic software provided by
a vendor that has undergone this certification. This means providing
documentation, test results, design information, and independent third
party review by an accredited lab. While open source software is
capable of meeting this, it does not meet FIPS-140 unless the vendor
submits to this process. Rationale:DoD Information Systems are required to use FIPS-approved cryptographic hash
functions. The only SSHv2 hash algorithms meeting this requirement is SHA2. Identifiers:
CCE-91338-4 References:
1, 12, 13, 15, 16, 5, 8, APO01.06, APO13.01, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.07, DSS06.02, DSS06.03, 3.1.13, 3.13.11, 3.13.8, CCI-000068, CCI-000803, CCI-000877, CCI-001453, CCI-003123, 164.308(b)(1), 164.308(b)(2), 164.312(e)(1), 164.312(e)(2)(i), 164.312(e)(2)(ii), 164.314(b)(2)(i), 4.3.3.5.1, 4.3.3.6.6, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.6, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.11.2.6, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-6(a), AC-17(a), AC-17(2), SC-13, MA-4(6), SC-12(2), SC-12(3), PR.AC-1, PR.AC-3, PR.DS-5, PR.PT-4, 2.2.7, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000394-GPOS-00174, SLES-15-010270, 5.2.14, SV-234826r877395_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value sshd_approved_macs # promote to variable
set_fact:
sshd_approved_macs: !!str hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256
tags:
- always
- name: Use Only FIPS 140-2 Validated MACs
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MACs\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MACs\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*MACs\s+
line: MACs {{ sshd_approved_macs }}
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91338-4
- DISA-STIG-SLES-15-010270
- NIST-800-171-3.1.13
- NIST-800-171-3.13.11
- NIST-800-171-3.13.8
- NIST-800-53-AC-17(2)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(6)
- NIST-800-53-SC-12(2)
- NIST-800-53-SC-12(3)
- NIST-800-53-SC-13
- PCI-DSSv4-2.2.7
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_use_approved_macs
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
sshd_approved_macs='hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512,hmac-sha2-256'
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^MACs")
# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "$sshd_approved_macs"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^MACs\\>" "/etc/ssh/sshd_config"; then
escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
LC_ALL=C sed -i --follow-symlinks "s/^MACs\\>.*/$escaped_formatted_output/gi" "/etc/ssh/sshd_config"
else
if [[ -s "/etc/ssh/sshd_config" ]] && [[ -n "$(tail -c 1 -- "/etc/ssh/sshd_config" || true)" ]]; then
LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/ssh/sshd_config"
fi
cce="CCE-91338-4"
printf '# Per %s: Set %s in %s\n' "${cce}" "${formatted_output}" "/etc/ssh/sshd_config" >> "/etc/ssh/sshd_config"
printf '%s\n' "$formatted_output" >> "/etc/ssh/sshd_config"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Use Only Strong Key Exchange algorithms
[ref]ruleLimit the Key Exchange to strong algorithms.
The following line in /etc/ssh/sshd_config demonstrates use
of those:
KexAlgorithms ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256 Rationale:Key exchange is any method in cryptography by which cryptographic keys are exchanged
between two parties, allowing use of a cryptographic algorithm. If the sender and receiver
wish to exchange encrypted messages, each must be equipped to encrypt messages to be
sent and decrypt messages received Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
- name: XCCDF Value sshd_strong_kex # promote to variable
set_fact:
sshd_strong_kex: !!str ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256
tags:
- always
- name: Use Only Strong Key Exchange algorithms
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*KexAlgorithms\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*KexAlgorithms\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*KexAlgorithms\s+
line: KexAlgorithms {{ sshd_strong_kex }}
state: present
insertbefore: BOF
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-92626-1
- PCI-DSS-Req-2.3
- PCI-DSSv4-2.2.7
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_use_strong_kex
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
sshd_strong_kex='ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256'
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*KexAlgorithms\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "KexAlgorithms $sshd_strong_kex" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on SSH Server config file
[ref]rule
To properly set the permissions of /etc/ssh/sshd_config , run the command:
$ sudo chmod 0600 /etc/ssh/sshd_config Rationale:Service configuration files enable or disable features of their respective
services that if configured incorrectly can lead to insecure and vulnerable
configurations. Therefore, service configuration files should be owned by the
correct group to prevent unauthorized changes. Identifiers:
CCE-91306-1 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-17(a), CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, 5.2.1 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Test for existence /etc/ssh/sshd_config
stat:
path: /etc/ssh/sshd_config
register: file_exists
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-91306-1
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_sshd_config
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure permission u-xs,g-xwrs,o-xwrt on /etc/ssh/sshd_config
file:
path: /etc/ssh/sshd_config
mode: u-xs,g-xwrs,o-xwrt
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- file_exists.stat is defined and file_exists.stat.exists
tags:
- CCE-91306-1
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_sshd_config
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
chmod u-xs,g-xwrs,o-xwrt /etc/ssh/sshd_config
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on SSH Server Private *_key Key Files
[ref]ruleSSH server private keys - files that match the /etc/ssh/*_key glob, have to have restricted permissions.
If those files are owned by the root user and the root group, they have to have the 0640 permission or stricter. Rationale:If an unauthorized user obtains the private SSH host key file, the host could be
impersonated. Identifiers:
CCE-85644-3 References:
BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.13, 3.13.10, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-17(a), CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-2.2.4, 2.2.6, SRG-OS-000480-GPOS-00227, SLES-15-040250, 5.2.2, SV-235009r880958_rule Remediation Puppet snippet: (show)
include ssh_private_key_perms
class ssh_private_key_perms {
exec { 'sshd_priv_key':
command => "chmod 0640 /etc/ssh/*_key",
path => '/bin:/usr/bin'
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Find root:root-owned keys
ansible.builtin.command: find -H /etc/ssh/ -maxdepth 1 -user root -regex ".*_key$"
-type f -group root -perm /u+xs,g+xws,o+xwrt
register: root_owned_keys
changed_when: false
failed_when: false
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85644-3
- DISA-STIG-SLES-15-040250
- NIST-800-171-3.1.13
- NIST-800-171-3.13.10
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_sshd_private_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for root:root-owned keys
ansible.builtin.file:
path: '{{ item }}'
mode: u-xs,g-xws,o-xwrt
state: file
with_items:
- '{{ root_owned_keys.stdout_lines }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85644-3
- DISA-STIG-SLES-15-040250
- NIST-800-171-3.1.13
- NIST-800-171-3.13.10
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_sshd_private_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
for keyfile in /etc/ssh/*_key; do
test -f "$keyfile" || continue
if test root:root = "$(stat -c "%U:%G" "$keyfile")"; then
chmod u-xs,g-xws,o-xwrt "$keyfile"
else
echo "Key-like file '$keyfile' is owned by an unexpected user:group combination"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Verify Permissions on SSH Server Public *.pub Key Files
[ref]rule To properly set the permissions of /etc/ssh/*.pub , run the command: $ sudo chmod 0644 /etc/ssh/*.pub Rationale:If a public host key file is modified by an unauthorized user, the SSH service
may be compromised. Identifiers:
CCE-85643-5 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.13, 3.13.10, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-17(a), CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-2.2.4, 2.2.6, SRG-OS-000480-GPOS-00227, SLES-15-040240, 5.2.3, SV-235008r622137_rule Remediation Puppet snippet: (show)
include ssh_public_key_perms
class ssh_public_key_perms {
exec { 'sshd_pub_key':
command => "chmod 0644 /etc/ssh/*.pub",
path => '/bin:/usr/bin'
}
}
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
- name: Find /etc/ssh/ file(s)
command: find -H /etc/ssh/ -maxdepth 1 -perm /u+xs,g+xws,o+xwt -type f -regex "^.*\.pub$"
register: files_found
changed_when: false
failed_when: false
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85643-5
- DISA-STIG-SLES-15-040240
- NIST-800-171-3.1.13
- NIST-800-171-3.13.10
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_sshd_pub_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /etc/ssh/ file(s)
file:
path: '{{ item }}'
mode: u-xs,g-xws,o-xwt
state: file
with_items:
- '{{ files_found.stdout_lines }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85643-5
- DISA-STIG-SLES-15-040240
- NIST-800-171-3.1.13
- NIST-800-171-3.13.10
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-2.2.4
- PCI-DSSv4-2.2.6
- configure_strategy
- file_permissions_sshd_pub_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | false |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
find -H /etc/ssh/ -maxdepth 1 -perm /u+xs,g+xws,o+xwt -type f -regex '^.*\.pub$' -exec chmod u-xs,g-xws,o-xwt {} \;
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
|
Ensure nonessential services are removed or masked
[ref]ruleA network port is identified by its number, the associated IP address,
and the type of the communication protocol such as TCP or UDP.
A listening port is a network port on which an application or process
listens on, acting as a communication endpoint.
Each listening port can be open or closed (filtered) using a firewall.
In general terms, an open port is a network port that accepts
incoming packets from remote locations. Rationale:Services listening on the system pose a potential risk as an attack vector. These services should be reviewed, and if not required, the service should be stopped, and the package containing the service should be removed. If required packages have a dependency, the service should be stopped and masked to reduce the attack surface of the system. Identifiers:
CCE-92463-9 References:
2.2.4, 2.4 |