SV-281349r1167197: RHEL 10 must not respond to Internet Control Message Protocol (ICMP) echoes sent to a broadcast address. | Red Hat Enterprise Linux 10 STIG SCAP Benchmark

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Assessment Title

Rule Text

RHEL 10 must not respond to Internet Control Message Protocol (ICMP) echoes sent to a broadcast address.

Description

Discussion Text

Responding to broadcast (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks. Ignoring ICMP echo requests (pings) sent to broadcast or multicast addresses makes the system slightly more difficult to enumerate on the network. Satisfies: SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00080

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

IA Controls

NIST SP 800-53

Not mappedCCI-002385Not mappedCCI-001104

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:281349
# RHEL 10 must not respond to Internet Control Message Protocol (ICMP) echoes sent to a broadcast address.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# net.ipv4.icmp_echo_ignore_broadcasts is set to 1 in kernel
# sysctl_object (sysctl_test)
test_1() {
  [ "$(cat /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts)" -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 Definition: oval:mil.disa.stig.rhel10os:def:281349

if [ ! -f "/etc/sysctl.d/ipv4_icmp_echo_ignore_broadcasts.conf" ]; then
    echo "FAIL"
    exit 1
fi

if [ ! -s "/etc/sysctl.d/ipv4_icmp_echo_ignore_broadcasts.conf" ]; then
    echo "FAIL"
    exit 1
fi

if grep -qF "net.ipv4.icmp_echo_ignore_broadcasts = 1" /etc/sysctl.d/ipv4_icmp_echo_ignore_broadcasts.conf; then
    echo "PASS"
    exit 0
else
    echo "FAIL"
    exit 1
fi

Remediation

Configure RHEL 10 to ignore Internet Protocol version 4 (IPv4) ICMP echoes sent to a broadcast address.

Create a configuration file if it does not already exist:

$ sudo vi /etc/sysctl.d/ipv4_icmp_echo_ignore_broadcasts.conf

Add the following line to the file:

net.ipv4.icmp_echo_ignore_broadcasts = 1

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

$ sudo sysctl --system