The perimeter router must be configured to block all packets with any IP options.
An XCCDF Rule
Description
<VulnDiscussion>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.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-256060r945859_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
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
!