The Cisco perimeter router must be configured to drop IPv6 packets containing the NSAP address option within Destination Option header.
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 from RFC 1888 (OSI NSAPs and IPv6) has been deprecated by RFC 4048.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-230156r855850_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
Configure the router to to drop IPv6 packets containing the NSAP address option within Destination Option header as shown in the example below.
R1(config)#ipv6 access-list FILTER_IPV6
R1(config-ipv6-acl)#deny 60 any any dest-option-type 195 log
R1(config-ipv6-acl)#permit …
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