The Cisco perimeter switch must be configured to block all packets with any IP options.
An XCCDF Rule
Description
<VulnDiscussion>Packets with IP options are not fast switched and henceforth must be punted to the switch processor. Hackers who initiate denial-of-service (DoS) attacks on switches commonly send large streams of packets with IP options. Dropping the packets with IP options reduces the load of IP options packets on the switch. The end result is a reduction in the effects of the DoS attack on the switch and on downstream switches.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-221015r856410_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
Configure the switch to drop all packets with IP options.
SW1(config)#ip access-list extended EXTERNAL_ACL
SW1(config-ext-nacl)#15 deny ip any any option any-options