Rule ID
SV-45719r1_rule
Version
V1R12
CCIs
Source-routed packets allow the source of the packet to suggest 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.
Verify the system does not accept source-routed IPv4 packets. Procedure: # grep [01] /proc/sys/net/ipv4/conf/*/accept_source_route|egrep "default|all" If all of the returned lines do not end with 0, this is a finding. Note: The same setting is used by Linux for both the local acceptance and forwarding of source-routed IPv4 packets.
Configure the system to not accept source-routed IPv4 packets. Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.accept_source_route=0" and "net.ipv4.conf.default.accept_source_route=0". Reload the sysctls. Procedure: # sysctl -p