SV-257868r958804: RHEL 9 must mount /tmp with the nosuid option. | Red Hat Enterprise Linux 9 STIG SCAP Benchmark

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Assessment Title

Rule Text

RHEL 9 must mount /tmp with the nosuid option.

Description

Discussion Text

The "nosuid" mount option causes the system to not execute "setuid" and "setgid" files with owner privileges. This option must be used for mounting any file system not containing approved "setuid" and "setguid" files. Executing files from untrusted file systems increases the opportunity for nonprivileged users to attain unauthorized administrative access.

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

IA Controls

NIST SP 800-53

Not mappedCCI-001764

References

DPMS Target Red Hat Enterprise Linux 9 DISA DPMS Target Red Hat Enterprise Linux 9 5551

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.stig.rhel9os:def:257868
# RHEL 9 must mount /tmp with the nosuid option.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# partition_object (partition_test)
test_1() {
  (findmnt -n -o OPTIONS '/tmp' | tr ',' '\n') | grep -qxF 'nosuid'
}
# textfilecontent54_object (textfilecontent54_test)
test_2() {
  (sed -En 's/^\s*[^#\s]+\s+\/tmp\s+\S+\s+(\S+)\s+\S+\s+\S+\s*$/\1/p' '/etc/fstab') | grep -Pq '^.*nosuid.*$'
}

if ( test_1 && test_2 ); 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:mil.disa.stig.rhel9os:def:257868

if grep -q "^/tmp.*nosuid" /etc/fstab && grep -q "^\\s*/tmp.*nosuid.*" /etc/fstab >/dev/null; then
    echo "PASS"
    exit 0
else
    echo "FAIL"
    exit 1
fi

Remediation

Modify "/etc/fstab" to use the "nosuid" option on the "/tmp" directory.