The perimeter router must be configured to block all packets with any IP options.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-256060	SRG-NET-000205-RTR-000015	ARST-RT-000830	SV-256060r945859_rule	2025-02-20	2

Description
Packets with IP options are not fast routered and henceforth must be punted to the router processor. Hackers who initiate denial-of-service (DoS) attacks on routers commonly send large streams of packets with IP options. Dropping the packets with IP options reduces the load of IP options packets on the router. The end result is a reduction in the effects of the DoS attack on the router and on downstream routers.

Description

Packets with IP options are not fast routered and henceforth must be punted to the router processor. Hackers who initiate denial-of-service (DoS) attacks on routers commonly send large streams of packets with IP options. Dropping the packets with IP options reduces the load of IP options packets on the router. The end result is a reduction in the effects of the DoS attack on the router and on downstream routers.

ℹ️ Check
Verify the perimeter router is configured to block all packets with any IP options with the following command: router#show run \| section IP_Option_ACL IP Access List IP_Option_ACL 10 deny ip any any ip-length gt 5 20 deny any log ! interface Ethernet25 description STIG_IP_Option_ACL ip access-group IP_Option_ACL in ! If the perimeter router is not configured to block packets with IP options, this is a finding.

ℹ️ Check

Verify the perimeter router is configured to block all packets with any IP options with the following command: router#show run | section IP_Option_ACL IP Access List IP_Option_ACL 10 deny ip any any ip-length gt 5 20 deny any log ! interface Ethernet25 description STIG_IP_Option_ACL ip access-group IP_Option_ACL in ! If the perimeter router is not configured to block packets with IP options, this is a finding.

✔️ Fix
Configure the perimeter router to block packets with IP options with the following commands: router#config router(config)# ip access-list IP_Option_ACL 10 deny ip any any ip-length gt 5 ! router(config)#interface Ethernet25 ip access-group IP_Option_ACL in !