TOSS must not forward IPv4 source-routed packets.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-253125 | TOSS-04-040840 | SV-253125r991589_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 forwarding is enabled and the system is functioning as a router. | ||||
| STIG | Date | |||
| Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide | 2025-05-08 | |||
Details
Check Text (C-253125r991589_chk)
Verify TOSS does not accept IPv4 source-routed packets.
Note: If IPv4 is disabled on the system, this requirement is Not Applicable.
Check the value of the accept source route variable with the following command:
$ sudo 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-56528r825046_fix)
Configure TOSS to not forward IPv4 source-routed packets with the following command:
$ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0
If "0" is not the system's all value then add or update the following line in the appropriate file under "/etc/sysctl.d":
net.ipv4.conf.all.accept_source_route=0