CISC-RT-000394 - The Cisco perimeter router must be configured to drop IPv6 packets containing a Hop-by-Hop header with invalid option type values.

Information

These options are intended to be for the Destination Options 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 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.

Solution

Drop IPv6 packets containing a Hop-by-Hop 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 hbh any any dest-option-type 4 log
RP/0/0/CPU0:R3(config-ipv6-acl)# deny hbh any any dest-option-type 195 log
RP/0/0/CPU0:R3(config-ipv6-acl)# deny hbh any any dest-option-type home-address 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

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Cisco_IOS-XR_Router_Y24M07_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-7(11), CAT|II, CCI|CCI-002403, Rule-ID|SV-230147r856667_rule, STIG-ID|CISC-RT-000394, Vuln-ID|V-230147

Plugin: Cisco

Control ID: fd68fce678fcfc2ec3102c01f96a51099ddaf9f0f59207949bb64072da6cdc67