SV-37400r1: Crontab files must be group-owned by root, cron, or the crontab creator's primary group. | Red Hat Enterprise Linux 5 Security Technical Implementation Guide

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Assessment Title

Rule Text

Crontab files must be group-owned by root, cron, or the crontab creator's primary group.

Description

Discussion Text

To protect the integrity of scheduled system jobs and prevent malicious modification to these jobs, crontab files must be secured.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000225

Additional Details

Responsibility

System Administrator

IA Controls

ECLP-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:195
# Crontab files must be group-owned by root, cron, or the crontab creator's primary group.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.
#
# MANUAL REVIEW REQUIRED -- the module(s) below could not be reconstructed
# into working code from curated SCC reference data, and are excluded from
# the automated result:
#   - file_object (file_test) -- check /var/spool/cron is is group-owned by root: no extractor for field "group_id"
#   - file_object (file_test) -- check /etc/cron.d is group-owned by root: no extractor for field "group_id"
#   - file_object (file_test) -- check /etc/cron.daily is group-owned by root: no extractor for field "group_id"
#   - file_object (file_test) -- check /etc/cron.hourly is group-owned by root: no extractor for field "group_id"
#   - file_object (file_test) -- check /etc/cron.monthly is group-owned by root: no extractor for field "group_id"
#   - file_object (file_test) -- check /etc/cron.weekly is group-owned by root: no extractor for field "group_id"

# check /etc/crontab is group-owned by root
# file_object (file_test)
test_3() {
  [ "$(stat -c '%g' '/etc/crontab')" -eq 0 ]
}

if test_3; then
  echo "PASS (automated portion only -- MANUAL REVIEW still required, see notes above)"
else
  echo "FAIL (or see MANUAL REVIEW note above)"
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:195
if [ ! -d "/var/spool/cron" ]; then echo "PASS"; exit 0; fi
for file in /var/spool/cron/*; do [ -f "$file" ] && [ $(stat -c "%G" "$file") = "root" ] && echo "PASS" && exit 0; done
echo "FAIL"; exit 1
if [ ! -d "/etc/cron.d" ]; then echo "PASS"; exit 0; fi
for file in /etc/cron.d/*; do [ -f "$file" ] && [ $(stat -c "%G" "$file") = "root" ] && echo "PASS" && exit 0; done
echo "FAIL"; exit 1
if [ ! -f "/etc/crontab" ]; then echo "PASS"; exit 0; fi
[ $(stat -c "%G" "/etc/crontab") = "root" ] && echo "PASS" && exit 0
echo "FAIL"; exit 1
if [ ! -d "/etc/cron.daily" ]; then echo "PASS"; exit 0; fi
for file in /etc/cron.daily/*; do [ -f "$file" ] && [ $(stat -c "%G" "$file") = "root" ] && echo "PASS" && exit 0; done
echo "FAIL"; exit 1
if [ ! -d "/etc/cron.hourly" ]; then echo "PASS"; exit 0; fi
for file in /etc/cron.hourly/*; do [ -f "$file" ] && [ $(stat -c "%G" "$file") = "root" ] && echo "PASS" && exit 0; done
echo "FAIL"; exit 1
if [ ! -d "/etc/cron.monthly" ]; then echo "PASS"; exit 0; fi
for file in /etc/cron.monthly/*; do [ -f "$file" ] && [ $(stat -c "%G" "$file") = "root" ] && echo "PASS" && exit 0; done
echo "FAIL"; exit 1

Remediation

Change the group owner of the crontab file to root, cron, or the crontab's primary group.
Procedure:
# chgrp root [crontab file]