SV-37624r1: Proxy Address Resolution Protocol (Proxy ARP) must not be enabled on the system. | Red Hat Enterprise Linux 5 Security Technical Implementation Guide

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Assessment Title

Rule Text

Proxy Address Resolution Protocol (Proxy ARP) must not be enabled on the system.

Description

Discussion Text

Proxy ARP allows a system to respond to ARP requests on one interface on behalf of hosts connected to another interface. If this function is enabled when not required, addressing information may be leaked between the attached network segments.

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

IA Controls

NIST SP 800-53

Not mappedCCI-001551

Additional Details

Responsibility

System Administrator

IA Controls

ECSC-1

References

DPMS Target Red Hat 5 DISA DPMS Target Red Hat 5 2154

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.fso.rhel11:def:241
# Proxy Address Resolution Protocol (Proxy ARP) must not be enabled on the system.
# 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.proxy_arp = 0
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  (sed -En 's/^([0-9]+)$/\1/p' '/proc/sys/net/ipv4/conf/all/proxy_arp') | grep -qxF '0'
}
# net.ipv4.conf.default.proxy_arp = 0
# textfilecontent54_object (textfilecontent54_test)
test_2() {
  (sed -En 's/^([0-9]+)$/\1/p' '/proc/sys/net/ipv4/conf/default/proxy_arp') | grep -qxF '0'
}

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 Definition: oval:mil.disa.fso.rhel11:def:241
if [ ! -f "/etc/sysctl.conf" ]; then echo "PASS"; exit 0; fi
if grep -q "^net.ipv4.conf.all.proxy_arp=0$" /etc/sysctl.conf && grep -q "^net.ipv4.conf.default.proxy_arp=0$" /etc/sysctl.conf; then echo "PASS"; exit 0; else echo "FAIL"; exit 1; fi

Remediation

Configure the system to not use proxy ARP.
Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.proxy_arp=0" and "net.ipv4.conf.default.proxy_arp=0".
# sysctl -p