Detections
Analytics

CISC-RT-000398 - The Cisco perimeter router must be configured to drop IPv6 packets containing a Hop-by-Hop or Destination Option extension header with an undefined option type.

Information

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.

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

Configure the router to drop all inbound IPv6 packets containing an undefined option type value regardless of whether they appear in a Hop-by-Hop or 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 any any dest-option-type 2
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 3
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 6
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 9
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 10
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 11
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 12
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 13
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 14
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 16
 ...
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 34
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 36
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 37
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 39
...
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 47
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 49
...
RP/0/0/CPU0:R3(config-ipv6-acl)# deny any any dest-option-type 255
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_Y24M10_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-7(11), CAT|II, CCI|CCI-002403, Rule-ID|SV-230160r856675_rule, STIG-ID|CISC-RT-000398, Vuln-ID|V-230160

Plugin: Cisco

Control ID: 4def3002a6cc24ef681f7c5915ff55782c54d11b296bb95447b17132339a0479