The Cisco perimeter router must be configured to drop IPv6 packets containing a Destination Option header with invalid option type values.
An XCCDF Rule
Description
<VulnDiscussion>These options are intended to be for the Hop-by-Hop header only. 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. Hence, this 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.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-230151r856669_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
Configure the router to drop IPv6 packets containing a Destination Option header with option type values of 0x05 (Router Alert) or 0xC2 (Jumbo Payload) as shown in the example below.
RP/0/0/CPU0:R3(config)# ipv6 access-list FILTER_IPV6
RP/0/0/CPU0:R3(config-ipv6-acl)# deny 60 any any dest-option-type 5 log
RP/0/0/CPU0:R3(config-ipv6-acl)# deny 60 any any dest-option-type 194 log
RP/0/0/CPU0:R3(config-ipv6-acl)# permit ipv6 …