SV-281356r1167218: RHEL 10 must not forward Internet Protocol version 6 (IPv6) source-routed packets. | Red Hat Enterprise Linux 10 STIG SCAP Benchmark

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Assessment Title

Rule Text

RHEL 10 must not forward Internet Protocol version 6 (IPv6) source-routed packets.

Description

Discussion Text

Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when forwarding is enabled and the system is functioning as a router. Satisfies: SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00087

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

IA Controls

NIST SP 800-53

Not mappedCCI-002385Not mappedCCI-001111

References

DPMS Target Red Hat Enterprise Linux 10 DISA DPMS Target Red Hat Enterprise Linux 10 5733

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.rhel10os:def:281356
# RHEL 10 must not forward Internet Protocol version 6 (IPv6) source-routed packets.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# net.ipv6.conf.all.accept_source_route setting in kernel is 0
# sysctl_object (sysctl_test)
test_1() {
  [ "$(cat /proc/sys/net/ipv6/conf/all/accept_source_route)" -eq 0 ]
}

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.stig.rhel10os:def:281356

if ! command -v sysctl >/dev/null 2>&1; then
    echo "FAIL"
    exit 1
fi

if [ ! -f /etc/sysctl.d/ipv6_accept_source_route.conf ]; then
    echo "PASS"
    exit 0
fi

if grep -qF "net.ipv6.conf.all.accept_source_route = 0" /etc/sysctl.d/ipv6_accept_source_route.conf; then
    echo "PASS"
    exit 0
fi

echo "FAIL"
exit 1

Remediation

Configure RHEL 10 to not accept IPv6 source-routed packets.

Create a configuration file if it does not already exist:

$ sudo vi /etc/sysctl.d/ipv6_accept_source_route.conf

Add the following line to the file:

net.ipv6.conf.all.accept_source_route = 0

Reload settings from all system configuration files with the following command:

$ sudo sysctl --system