The SUSE operating system must not forward Internet Protocol version 4 (IPv4) source-routed packets by default.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-217289 | SLES-12-030370 | SV-217289r991589_rule | CCI-000366 | medium |
| Description | ||||
| Source-routed packets allow the source of the packet to suggest that 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. | ||||
| STIG | Date | |||
| SUSE Linux Enterprise Server 12 Security Technical Implementation Guide | 2025-05-14 | |||
Details
Check Text (C-217289r991589_chk)
Verify the SUSE operating system does not accept IPv4 source-routed packets by default.
Check the value of the default accept source route variable with the following command:
# sysctl net.ipv4.conf.default.accept_source_route
net.ipv4.conf.default.accept_source_route = 0
If the returned line does not have a value of "0" this is a finding.
Fix Text (F-18515r370024_fix)
Configure the SUSE operating system to the required kernel parameter by adding the following line to "/etc/sysctl.conf" (or modify the line to have the required value):
net.ipv4.conf.default.accept_source_route = 0
Run the following command to apply this value:
# sysctl --system