Detections
Analytics

6.2.3.8 Ensure events that modify user/group information are collected

Information

Record events affecting the modification of user or group information, including that of passwords and old passwords if in use.

 - /etc/group - system groups
 - /etc/passwd - system users
 - /etc/gshadow - encrypted password for each group
 - /etc/shadow - system user passwords
 - /etc/security/opasswd - storage of old passwords if the relevant PAM module is in use
 - /etc/nsswitch.conf - file configures how the system uses various databases and name resolution mechanisms
 - /etc/pam.conf - file determines the authentication services to be used, and the order in which the services are used.
 - /etc/pam.d - directory contains the PAM configuration files for each PAM-aware application.

The parameters in this section will watch the files to see if they have been opened for write or have had attribute changes (e.g. permissions) and tag them with the identifier "identity" in the audit log file.

Unexpected changes to these files could be an indication that the system has been compromised and that an unauthorized user is attempting to hide their activities or compromise additional accounts.

Satisfies: SRG-OS-000062-GPOS-00031, 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-000476-GPOS-00221

Solution

Edit or create a file in the /etc/audit/rules.d/ directory, ending in .rules extension, with the relevant rules to monitor events that modify user/group information.

Example:

# printf "
-w /etc/group -p wa -k identity
-w /etc/passwd -p wa -k identity
-w /etc/gshadow -p wa -k identity
-w /etc/shadow -p wa -k identity
-w /etc/security/opasswd -p wa -k identity
-w /etc/nsswitch.conf -p wa -k identity
-w /etc/pam.conf -p wa -k identity
-w /etc/pam.d -p wa -k identity
" >> /etc/audit/rules.d/50-identity.rules

Merge and load the rules into active configuration:

# augenrules --load

Check if reboot is required.

# if [[ $(auditctl -s | grep "enabled") =~ "2" ]]; then printf "Reboot required to load rules\n"; fi

See Also

https://workbench.cisecurity.org/benchmarks/25279

Item Details

Category: AUDIT AND ACCOUNTABILITY

References: 800-53|AU-12a., CSCv7|4.8, Rule-ID|SV-230404r627750_rule, Rule-ID|SV-230405r627750_rule, Rule-ID|SV-230406r627750_rule, Rule-ID|SV-230407r627750_rule, Rule-ID|SV-230408r627750_rule, Vuln-ID|V-230404, Vuln-ID|V-230405, Vuln-ID|V-230406, Vuln-ID|V-230407, Vuln-ID|V-230408

Plugin: Unix

Control ID: e8937f031ed4cdc9975e0c411592ab24227942069eeb9f60c2d9cc495ca51c1d