RHEL 9 must not respond to Internet Control Message Protocol (ICMP) echoes sent to a broadcast address.
An XCCDF Rule
Description
<VulnDiscussion>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.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-257966r942995_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
Configure RHEL 9 to not respond to IPv4 ICMP echoes sent to a broadcast address.
Add or edit the following line in a single system configuration file, in the "/etc/sysctl.d/" directory:
net.ipv4.icmp_echo_ignore_broadcasts = 1