RHEL 9 must not forward Internet Protocol version 4 (IPv4) source-routed packets.
An XCCDF Rule
Description
Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv4 forwarding is enabled and the system is functioning as a router. Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It must be disabled unless it is absolutely required.
- ID
- SV-257959r991589_rule
- Version
- RHEL-09-253020
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Configure RHEL 9 to ignore IPv4 source-routed packets.
Add or edit the following line in a single system configuration file, in the "/etc/sysctl.d/" directory:
net.ipv4.conf.all.accept_source_route = 0