OL 9 must not forward Internet Protocol version 4 (IPv4) source-routed packets.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-271865 | OL09-00-006021 | SV-271865r1092307_rule | Medium |
| 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-routed 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. |
| STIG | Date |
| Oracle Linux 9 Security Technical Implementation Guide | 2025-05-08 |
Details
| Check Text (C-75915r1092305_chk) |
| Verify that OL 9 will not accept IPv4 source-routed packets. Check the value of the all "accept_source_route" variables with the following command: $ sysctl net.ipv4.conf.all.accept_source_route net.ipv4.conf.all.accept_source_route = 0 If the returned line does not have a value of "0", a line is not returned, or the line is commented out, this is a finding. |
| Fix Text (F-75822r1092306_fix) |
| Configure OL 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 Load settings from all system configuration files with the following command: $ sudo sysctl --system |