RHEL 9 must not allow interfaces to perform Internet Control Message Protocol (ICMP) redirects by default.
An XCCDF Rule
Description
<VulnDiscussion>ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology. The ability to send ICMP redirects is only appropriate for systems acting as routers.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-257969r991589_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
Configure RHEL 9 to not allow interfaces to perform Internet Protocol version 4 (IPv4) ICMP redirects by default.
Add or edit the following line in a single system configuration file, in the "/etc/sysctl.d/" directory:
net.ipv4.conf.default.send_redirects = 0