The Cisco perimeter switch must be configured to drop IPv6 packets containing an extension header with the Endpoint Identification option.
An XCCDF Rule
Description
<VulnDiscussion>The optional and extensible natures of the IPv6 extension headers require higher scrutiny since many implementations do not always drop packets with headers that it cannot recognize, and hence could cause a Denial-of-Service on the target device. In addition, the type, length, value (TLV) formatting provides the ability for headers to be very large. This option type is associated with the Nimrod Routing system and has no defining RFC document.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-237773r856671_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
Configure the switch to drop IPv6 packets containing an option type values of 0x8A (Endpoint Identification) regardless of whether it appears in a Hop-by-Hop or Destination Option header as shown in the example below.
SW1(config)#ipv6 access-list FILTER_IPV6
SW1(config-ipv6-acl)#deny any any dest-option-type 138 log
SW1(config-ipv6-acl)#permit ipv6 …
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