The SUSE operating system must not forward Internet Protocol version 4 (IPv4) source-routed packets.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-217287 | SRG-OS-000480-GPOS-00227 | SLES-12-030360 | SV-217287r991589_rule | 2025-11-24 | 3 |
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.
ℹ️ Check
Verify the SUSE operating system does not accept IPv4 source-routed packets.
Check the value of the accept source route variable 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" this is a finding.
✔️ 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.all.accept_source_route = 0
Run the following command to apply this value:
# sysctl --system