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CIS Ubuntu 14.04 LTS - 4.1.5 Ensure events that modify user/group information are collected

DevOps & Security
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Collect audit events for modifications to user and group identity files

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_14.04_LTS_Benchmark_v2.1.0/cis-ubuntu1404-v210-4-1-5/SKILL.md

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4.1.5 Ensure events that modify user/group information are collected (Scored)

Profile Applicability

  • Level 2 - Server
  • Level 2 - Workstation

Description

Record events affecting the group, passwd (user IDs), shadow and gshadow (passwords) or /etc/security/opasswd (old passwords, based on remember parameter in the PAM configuration) files. 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.

Rationale

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.

Audit Procedure

Run the following commands:

grep identity /etc/audit/audit.rules
auditctl -l | grep identity

Expected Result

Verify output of both matches:

-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

Remediation

Add the following lines to the /etc/audit/audit.rules file:

-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

Notes: Reloading the auditd config to set active settings may require a system reboot.

Default Value

Not configured by default.

References

  1. CIS Controls v6.1 - 5.4 Log Administrative User Addition And Removal

Profile

  • Level 2 - Server
  • Level 2 - Workstation