AlmaLinux OS 9 must not respond to Internet Control Message Protocol (ICMP) echoes sent to a broadcast address.
An XCCDF Rule
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.
- ID
- SV-269248r1050130_rule
- Version
- ALMA-09-019050
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Configure AlmaLinux OS 9 to use reverse path filtering on all IP interfaces.
Create a numbered *.conf file in /etc/sysctl.d/ with the following content:
net.ipv4.icmp_echo_ignore_broadcasts = 1