Rule ID
SV-230151r1132534_rule
Version
V3R3
CCIs
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.
This requirement is not applicable for the DODIN Backbone. Review the router configuration to determine if it is compliant with this requirement. Step 1: Verify that an inbound IPv6 ACL has been configured on the external interface. interface interface gigabitethernet 0/2/0/2 ipv6 address 2001::1:0:22/64 ipv6 access-group FILTER_IPV6 ingress Step 2: Verify that the ACL drops 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. ipv6 access-list FILTER_IPV6 10 deny 60 any any dest-option log 20 permit ipv6 … … … … 90 deny ipv6 any any log Note: Cisco has deprecated the dest-option-type command used to filter by option type within the Destination Option header. Therefore, all packets with the Destination Option header must be dropped. If the router is not configured to drop IPv6 packets containing a Destination Option header, this is a finding.
Configure the router to drop IPv6 packets containing a Destination Option header 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 log RP/0/0/CPU0:R3(config-ipv6-acl)# permit ipv6 … … … … RP/0/0/CPU0:R3(config-ipv6-acl)# deny ipv6 any any log RP/0/0/CPU0:R3(config-ipv6-acl)# exit RP/0/0/CPU0:R3(config)# interface gigabitethernet 0/2/0/2 RP/0/0/CPU0:R3(config-if)# ipv6 access-group FILTER_IPV6 ingress RP/0/0/CPU0:R3(config-if)# end