The Red Hat Enterprise Linux operating system must not respond to Internet Protocol version 4 (IPv4) 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.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-204613r880809_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
Set the system to the required kernel parameter by adding the following line to "/etc/sysctl.conf" or a configuration file in the /etc/sysctl.d/ directory (or modify the line to have the required value):
net.ipv4.icmp_echo_ignore_broadcasts = 1
Issue the following command to make the changes take effect: