SV-258232r1184335: RHEL 9 IP tunnels must use FIPS 140-3 approved cryptographic algorithms. | Red Hat Enterprise Linux 9 STIG SCAP Benchmark

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Assessment Title

Rule Text

RHEL 9 IP tunnels must use FIPS 140-3 approved cryptographic algorithms.

Description

Discussion Text

Overriding the system crypto policy makes the behavior of the Libreswan service violate expectations, and makes system configuration more fragmented.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000068

References

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

Checks

DISA STIG (Manual Reference)

Verify that the IPsec service uses the system crypto policy with the following command:

Note: If the ipsec service is not installed, this requirement is Not Applicable.

$ sudo grep include /etc/ipsec.conf /etc/ipsec.d/*.conf

/etc/ipsec.conf:include /etc/crypto-policies/back-ends/libreswan.config

If the ipsec configuration file does not contain "include /etc/crypto-policies/back-ends/libreswan.config", this is a finding.

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:258232
# RHEL 9 IP tunnels must use FIPS 140-3 approved cryptographic algorithms.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# ipsec.conf includes crypto-policy
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  (sed -En 's/^\s*include\s+(.*)\s*$/\1/p' '/etc/ipsec.conf') | grep -qxF '/etc/crypto-policies/back-ends/libreswan.config'
}
# ipsec.conf includes /etc/ipsec.d/*.conf
# textfilecontent54_object (textfilecontent54_test)
test_2() {
  (sed -En 's/^\s*include\s+(.*)\s*$/\1/p' '/etc/ipsec.conf') | grep -qxF '/etc/ipsec.d/*.conf'
}
# /etc/ipsec.d/*.conf includes crypto-policy
# textfilecontent54_object (textfilecontent54_test)
test_3() {
  (grep -rhP --include='*.conf' '^\s*include\s+(.*)\s*$' '/etc/ipsec.d' | sed -En 's/^\s*include\s+(.*)\s*$/\1/p') | grep -qxF '/etc/crypto-policies/back-ends/libreswan.config'
}

if ( test_1 || ( test_2 && test_3 ) ); 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.stig.rhel9os:def:258232

ipsec_conf=$(cat /etc/ipsec.conf)
if echo "$ipsec_conf" | grep -q "^\\s*include\\s+/etc/crypto-policies/back-ends/libreswan.config\\s*$"; then
  echo "PASS"
  exit 0
fi

if [ ! -f "/etc/ipsec.d" ]; then
  echo "PASS"
  exit 0
fi

for file in /etc/ipsec.d/*.conf; do
  if [ -f "$file" ]; then
    conf_content=$(cat "$file")
    if echo "$conf_content" | grep -q "^\\s*include\\s+/etc/crypto-policies/back-ends/libreswan.config\\s*$"; then
      echo "PASS"
      exit 0
    fi
  fi
done

echo "FAIL"
exit 1

Remediation

Configure Libreswan to use the system cryptographic policy.

Add the following line to "/etc/ipsec.conf":

include /etc/crypto-policies/back-ends/libreswan.config