V-221894

Discussion

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 IPv6 forwarding is enabled and the system is functioning as a router.

Check Content

If IPv6 is not enabled, the key will not exist, and this is Not Applicable.

Verify the system does not accept IPv6 source-routed packets.

     # grep -r net.ipv6.conf.all.accept_source_route /run/sysctl.d/* /etc/sysctl.d/* /usr/local/lib/sysctl.d/* /usr/lib/sysctl.d/* /lib/sysctl.d/* /etc/sysctl.conf 2> /dev/null
     net.ipv6.conf.all.accept_source_route = 0

If "net.ipv6.conf.all.accept_source_route" is not configured in the /etc/sysctl.conf file or in any of the other sysctl.d directories, is commented out or does not have a value of "0", this is a finding.

Check that the operating system implements the accept source route variable with the following command:

     # /sbin/sysctl -a | grep net.ipv6.conf.all.accept_source_route
     net.ipv6.conf.all.accept_source_route = 0

If the returned lines do not have a value of "0", this is a finding.

If conflicting results are returned, this is a finding.