SV-271866r1092310: OL 9 must log IPv4 packets with impossible addresses. | Oracle Linux 9 STIG SCAP Benchmark

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Assessment Title

Rule Text

OL 9 must log IPv4 packets with impossible addresses.

Description

Discussion Text

The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected.

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:271866
# OL 9 must log IPv4 packets with impossible addresses.
# 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.log_martians setting in kernel set to 1
# sysctl_object (sysctl_test)
test_1() {
  [ "$(cat /proc/sys/net/ipv4/conf/all/log_martians)" -eq 1 ]
}

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:mil.disa.stig.ol9os:def:271866

if ! [ -f /proc/sys/net/ipv4/conf/all/log_martians ]; then
    echo "FAIL"
    exit 1
fi

if [ ! -r /proc/sys/net/ipv4/conf/all/log_martians ]; then
    echo "FAIL"
    exit 1
fi

value=$(cat /proc/sys/net/ipv4/conf/all/log_martians)

if [ "$value" -ne 1 ]; then
    echo "FAIL"
    exit 1
fi

echo "PASS"
exit 0

Remediation

Configure OL 9 to log martian packets on IPv4 interfaces.

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

net.ipv4.conf.all.log_martians=1

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

$ sudo sysctl --system