RHEL 10 must not respond to Internet Control Message Protocol (ICMP) echoes sent to a broadcast address.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-281349 | SRG-OS-000420-GPOS-00186 | RHEL-10-800170 | SV-281349r1167197_rule | 2026-03-11 | 1 |
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
ℹ️ Check
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
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