RHEL 10 must not respond to Internet Control Message Protocol (ICMP) echoes sent to a broadcast address.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-281349 | RHEL-10-800170 | SV-281349r1167197_rule | CCI-002385 | medium |
| Description | ||||
| 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 | ||||
| STIG | Date | |||
| Red Hat Enterprise Linux 10 Security Technical Implementation Guide | 2026-03-11 | |||
Details
Check Text (C-281349r1167197_chk)
Verify RHEL 10 ignores ICMP echoes sent to a broadcast address.
Check the value of the "net.ipv4.icmp_echo_ignore_broadcasts" variable with the following command:
$ sudo sysctl net.ipv4.icmp_echo_ignore_broadcasts
net.ipv4.icmp_echo_ignore_broadcasts = 1
If "net.ipv4.icmp_echo_ignore_broadcasts" is not set to "1" or is missing, this is a finding.
Fix Text (F-85815r1167196_fix)
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