The Cisco perimeter switch must be configured to drop IPv6 undetermined transport packets.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
|---|---|---|---|---|
| V-237761 | CISC-RT-000392 | SV-237761r856663_rule | Medium |
| Description |
|---|
| One of the fragmentation weaknesses known in IPv6 is the undetermined transport packet. This packet contains an undetermined protocol due to fragmentation. Depending on the length of the IPv6 extension header chain, the initial fragment may not contain the layer four port information of the packet. |
| STIG | Date |
|---|---|
| Cisco IOS Switch RTR Security Technical Implementation Guide | 2022-09-14 |
Details
| Check Text ( C-40976r856253_chk ) |
|---|
| This requirement is not applicable for the DODIN Backbone. Review the switch configuration to determine if it is configured to drop IPv6 undetermined transport packets. Step 1: Verify that an inbound IPv6 ACL has been configured on the external interface. interface gigabitethernet1/0 ipv6 address 2001::1:0:22/64 ipv6 traffic-filter FILTER_IPV6 in Step 2: Verify that the ACL drops undetermined transport packets as shown in the example below. ipv6 access-list FILTER_IPV6 deny ipv6 any any log undetermined-transport permit ipv6 … … … … deny ipv6 any any log If the switch is not configured to drop IPv6 undetermined transport packets, this is a finding. |
| Fix Text (F-40938r856254_fix) |
|---|
| Configure the switch to drop IPv6 undetermined transport packets as shown in the example below. SW1(config)#ipv6 access-list FILTER_IPV6 SW1(config-ipv6-acl)#deny ipv6 any any undetermined-transport log SW1(config-ipv6-acl)#permit ipv6 … … … … SW1(config-ipv6-acl)#deny ipv6 any any log SW1(config-ipv6-acl)#exit SW1(config)#int g1/0 SW1(config-if)#ipv6 traffic-filter FILTER_IPV6 in |