SLEM 5 must not forward Internet Protocol version 6 (IPv6) source-routed packets.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-261321SLEM-05-254010SV-261321r996433_ruleCCI-000366medium
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.
STIGDate
SUSE Linux Enterprise Micro (SLEM) 5 Security Technical Implementation Guide2025-05-08

Details

Check Text (C-261321r996433_chk)

Verify SLEM 5 does not accept IPv6 source-routed packets with the following command: > sudo sysctl net.ipv6.conf.all.accept_source_route net.ipv6.conf.all.accept_source_route = 0 If the network parameter "ipv6.conf.all.accept_source_route" is not equal to "0" or nothing is returned, this is a finding.

Fix Text (F-64958r996432_fix)

Configure SLEM 5 to disable IPv6 source routing by running the following command as an administrator: > sudo sysctl -w net.ipv6.conf.all.accept_source_route=0 If "0" is not the system's default value, add or update the following line in "/etc/sysctl.d/99-stig.conf": > sudo sh -c 'echo "net.ipv6.conf.all.accept_source_route=0" >> /etc/sysctl.d/99-stig.conf' > sudo sysctl --system