SV-253128r991589: TOSS must not respond to Internet Control Message Protocol (ICMP) echoes sent to a broadcast address. | Tri-Lab Operating System Stack (TOSS) 4 STIG SCAP Benchmark

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Assessment Title

Rule Text

TOSS 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. There are notable differences between Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6). IPv6 does not implement the same method of broadcast as IPv4. Instead, IPv6 uses multicast addressing to the all-hosts multicast group. Refer to RFC4294 for an explanation of "IPv6 Node Requirements", which resulted in this difference between IPv4 and IPv6.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000366

References

DPMS Target TOSS 4 DISA DPMS Target TOSS 4 5469

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.toss4os:def:253128
# TOSS 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
# DISA STIG / SCAP compliance check for TOSS not responding to ICMP echoes on broadcast address (oval:mil.disa.stig.toss4os:def:253128)
if [ ! -x "/usr/sbin/sysctl" ]; then echo "PASS"; exit 0; fi
if [ -z "$(sysctl -n net.ipv4.icmp_echo_ignore_broadcasts 2>/dev/null)" ] || [ "$(sysctl -n net.ipv4.icmp_echo_ignore_broadcasts 2>/dev/null)" -ne 1 ]; then echo "FAIL"; exit 1; fi
if ! grep -q "net.ipv4.icmp_echo_ignore_broadcasts=1" /etc/sysctl.d/* 2>/dev/null; then echo "FAIL"; exit 1; fi
echo "PASS"
exit 0

Remediation

Configure TOSS to not respond to IPv4 ICMP echoes sent to a broadcast address with the following command:

$ sudo sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1

If "1" is not the system's default value then add or update the following line in the appropriate file under "/etc/sysctl.d":

net.ipv4.icmp_echo_ignore_broadcasts=1