SV-27072r1: All GIDs referenced in the /etc/passwd file must be defined in the /etc/group file. | Red Hat Enterprise Linux 5 Security Technical Implementation Guide

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Assessment Title

Rule Text

All GIDs referenced in the /etc/passwd file must be defined in the /etc/group file.

Description

Discussion Text

If a user is assigned the GID of a group not existing on the system, and a group with the GID is subsequently created, the user may have unintended rights to the group.

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-000366

Additional Details

Responsibility

System Administrator

IA Controls

ECSC-1

References

DPMS Target Red Hat 5 DISA DPMS Target Red Hat 5 2154

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

#!/bin/bash
# Reconstructed from oval:mil.disa.fso.rhel11:def:43
# All GIDs referenced in the /etc/passwd file must be defined in the /etc/group file.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# groupids in /etc/passwd must exist in /etc/group
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  [ "$(sed -En 's/^[^:]+:[^:]+:[^:]+:([0-9]+)/\1/p' '/etc/passwd')" = "$(sed -En 's/^[^:]*:[^:]*:([0-9]+):/\1/p' '/etc/group')" ]
}

if test_1; then
  echo "PASS"
else
  echo "FAIL"
fi

Assessment Script Powered by AISandbox-executed

A standalone Shell script to assess this control automatically. Review before running it in your environment.

Syntax-checked and actually executed in an isolated sandbox (not the real system this checks) — confirmed to run without errors.

#!/bin/sh
# OVAL Definition: oval:mil.disa.fso.rhel11:def:43


if [ ! -f "/etc/passwd" ] || [ ! -f "/etc/group" ]; then echo "PASS"; exit 0; fi

gids_in_passwd=$(grep -oP '^[^:]+:[^:]+:[^:]+:[0-9]+' /etc/passwd | sort | uniq)

gids_in_group=$(grep -oP '^[^:]+:[^:]+:([0-9]+)' /etc/group | sort | uniq)

missing_gids=$(comm -23 <(echo "$gids_in_passwd") <(echo "$gids_in_group") | tr '\t' '\n')

if [ -z "$missing_gids" ]; then echo "PASS"; exit 0; fi

echo "FAIL"; exit 1

Remediation

Add a group to the system for each GID referenced without a corresponding group.