Detections
Analytics

6.2.3.13 Ensure events that modify /etc/shadow and /etc/gshadow are collected

Information

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

 - /etc/gshadow - encrypted password for each group
 - /etc/shadow - system user passwords

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/gshadow -p wa -k identity
-w /etc/shadow -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/26891

Item Details

Category: AUDIT AND ACCOUNTABILITY

References: 800-53|AU-3, 800-53|AU-3(1), 800-53|AU-7, 800-53|AU-12, 800-53|AU-12a., CSCv7|4.8, Rule-ID|SV-230404r1017210_rule, Rule-ID|SV-230407r1017213_rule, Rule-ID|SV-258228r991572_rule, Rule-ID|SV-258231r1069375_rule, Rule-ID|SV-260629r958368_rule, Rule-ID|SV-260632r958368_rule, Rule-ID|SV-269131r1050013_rule, Rule-ID|SV-269134r1050016_rule, Rule-ID|SV-270686r1066547_rule, Rule-ID|SV-270687r1066550_rule

Plugin: Unix

Control ID: 3057f8d7694df97f404a51f821163c79282188c34000c4242e24d44a0b9ebb29