The Cisco PE router must be configured to ignore or drop all packets with any IP options.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-217001	CISC-RT-000750	SV-217001r855844_rule		Medium

Description

Packets with IP options are not fast-switched and therefore 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 XE Router RTR Security Technical Implementation Guide	2023-09-13

Details

Check Text ( C-18231r288165_chk )
Review the router configuration to determine if it will ignore or drop all packets with IP options as shown in the examples below: ip options drop or ip options ignore If the router is not configured to drop or block all packets with IP options, this is a finding.

Fix Text (F-18229r288166_fix)
Configure the router to ignore or drop all packets with IP options as shown in the examples below: R4(config)#ip options ignore or R4(config)#ip options drop