cis-ubuntu1204-v110-13-11

name	cis-ubuntu1204-v110-13-11
description	Check Groups in /etc/passwd
category	cis-os-hardening
version	1.1.0
author	cyberstrike-official
tags	["cis","ubuntu",12.04,"linux","user-management","groups","passwd","consistency"]
cis_id	13.11
cis_benchmark	CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

13.11 Check Groups in /etc/passwd (Scored)

Profile Applicability

• Level 1

Description

Over time, system administration errors and changes can lead to groups being defined in /etc/passwd but not in /etc/group.

Rationale

Groups defined in the /etc/passwd file but not in the /etc/group file pose a threat to system security since group permissions are not properly managed.

Audit Procedure

Using Command Line

Create a script as shown below and run it:

#!/bin/bash
for i in $(cut -s -d: -f4 /etc/passwd | sort -u ); do
grep -q -P "^.*?:[^:]*:$i:" /etc/group
if [ $? -ne 0 ]; then
echo "Group $i is referenced by /etc/passwd but does not exist in /etc/group"
fi
done

Expected Result

No output should be returned. Any output indicates groups referenced in /etc/passwd that do not exist in /etc/group.

Remediation

Using Command Line

Analyze the output of the Audit step above and perform the appropriate action to correct any discrepancies found.

Default Value

All default system groups are properly defined in both /etc/passwd and /etc/group.

References

• CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0

Profile

Level 1 - Scored