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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-216990	CISC-RT-000350	SV-216990r856207_rule		Medium

Description

Packets with IP options are not fast switched 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.

STIG	Date
Cisco IOS Router RTR Security Technical Implementation Guide	2022-09-14

Details

Check Text ( C-18220r287298_chk )
This requirement is not applicable for the DODIN Backbone. Review the router configuration to determine if it will block all packets with IP options. ip access-list extended EXTERNAL_ACL permit tcp any any established deny ip any any option any-options permit … … … … deny ip any any log-input If the router is not configured to drop all packets with IP options, this is a finding.

Fix Text (F-18218r287299_fix)
This requirement is not applicable for the DODIN Backbone. Configure the router to drop all packets with IP options. R1(config)#ip access-list extended EXTERNAL_ACL R1(config-ext-nacl)#15 deny ip any any option any-options