SV-271872r1092328: OL 9 must not enable IPv4 packet forwarding unless the system is a router. | Oracle Linux 9 STIG SCAP Benchmark

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Assessment Title

Rule Text

OL 9 must not enable IPv4 packet forwarding unless the system is a router.

Description

Discussion Text

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this capability is used when not required, system network information may be unnecessarily transmitted across the network.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000366

References

DPMS Target Oracle Linux 9 DISA DPMS Target Oracle Linux 9 5680

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.ol9os:def:271872
# OL 9 must not enable IPv4 packet forwarding unless the system is a router.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# net.ipv4.conf.all.forwarding setting in kernel is 0
# sysctl_object (sysctl_test)
test_1() {
  [ "$(cat /proc/sys/net/ipv4/conf/all/forwarding)" -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.ol9os:def:271872

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

if [ ! -f /etc/sysctl.d/99-sysctl.conf ]; then
  echo "PASS"
  exit 0
fi

FORWARDING=$(sysctl -n net.ipv4.conf.all.forwarding 2>/dev/null || echo "unknown")
if [ "$FORWARDING" = "0" ]; then
  echo "PASS"
  exit 0
fi

echo "FAIL"
exit 1

Remediation

Configure OL 9 to not allow IPv4 packet forwarding unless the system is a router.

Add or edit the following line in a single system configuration file in the "/etc/sysctl.d/" directory:

net.ipv4.conf.all.forwarding = 0

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

$ sudo sysctl --system