CISC-RT-000040 - The Cisco switch must be configured to use encryption for routing protocol authentication.

Information

A rogue switch could send a fictitious routing update to convince a site's perimeter switch to send traffic to an incorrect or even a rogue destination. This diverted traffic could be analyzed to learn confidential information about the site's network or used to disrupt the network's ability to communicate with other networks. This is known as a 'traffic attraction attack' and is prevented by configuring neighbor switch authentication for routing updates. However, using clear-text authentication provides little benefit since an attacker can intercept traffic and view the authentication key. This would allow the attacker to use the authentication key in an attack.

This requirement applies to all IPv4 and IPv6 protocols that are used to exchange routing or packet forwarding information; this includes all Interior Gateway Protocols (such as OSPF, EIGRP, and IS-IS) and Exterior Gateway Protocols (such as BGP), MPLS-related protocols (such as LDP), and multicast-related protocols.

Solution

Configure all routing protocol authentications to encrypt the authentication key.

BGP Example:

Step 1: Configure a keychain for TCP-AO.

key chain <KEY-CHAIN-NAME> tcp
key <KEY-ID>
send-id <ID>
recv-id <ID>
cryptographic-algorithm hmac-sha-1
key-string <KEY>
accept-lifetime 00:00:00 Jan 1 2022 duration 180
send-lifetime 00:00:00 Jan 1 2022 duration 180
!

Step 2: Configure BGP autonomous system.

router bgp <ASN>
no synchronization
bgp log-neighbor-changes
neighbor x.x.x.x remote-as <ASN>
neighbor x.x.x.x ao <KEY-CHAIN-NAME>

EIGRP Example:

SW2(config)#int g0/1
SW2(config-if)#ip authentication mode eigrp 1 md5
SW2(config-if)#ip authentication key-chain eigrp 1 EIGRP_KEY_CHAIN

IS-IS Example:

SW1(config)#int g0/1
SW1(config-if)#isis authentication mode md5
SW1(config-if)#isis authentication key-chain ISIS_KEY_CHAIN

OSPF Example:

SW1(config)#key chain OSPF_KEY_CHAIN
SW1(config-keychain)#key 1
SW1(config-keychain-key)#key-string xxxxxx
SW1(config-keychain-key)#cryptographic-algorithm hmac-sha-256
SW1(config-keychain-key)#exit
SW1(config-keychain-key)#end
SW1(config)#interface GigabitEthernet0/2
SW1(config-if)#ip ospf authentication key-chain OSPF_KEY_CHAIN

RIP Example:

SW2(config)#int g1/0
SW2(config-if)#ip rip authentication mode md5
SW2(config-if)#ip rip authentication key-chain RIP_KEY_CHAIN

Item Details

Audit Name: DISA STIG Cisco IOS XE Switch RTR v2r4

Plugin: Cisco

Control ID: 412ab1672646442834253ec0a477a4ff4c826b7f3d7064a04221b5051a8d5d88

Detections

Analytics

CISC-RT-000040 - The Cisco switch must be configured to use encryption for routing protocol authentication.

Information

Solution

See Also

Item Details