RHEL 9 must use a reverse-path filter for IPv4 network traffic when possible by default.
An XCCDF Rule
Description
<VulnDiscussion>Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface on which they were received. It must not be used on systems that are routers for complicated networks, but is helpful for end hosts and routers serving small networks.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-257965r925882_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
Configure RHEL 9 to use reverse path filtering on IPv4 interfaces by default.
Add or edit the following line in a single system configuration file, in the "/etc/sysctl.d/" directory:
net.ipv4.conf.default.rp_filter = 1