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
SW1(config)#switch bgp nn
SW1(config-switch)#neighbor x.x.x.x password xxxxxx
EIGRP Example
SW1(config)# router eigrp 1
SW1(config-router)# authentication mode md5
SW1(config-router)# end
or
Authentication for the EIGRP neighbor
SW1(config)# int e2/21
SW1(config-if)# ip authentication mode eigrp 1 md5
SW1(config-if)# end
Note: Interface authentication overrides process authentication.
IS-IS Example
SW1(config)# int e2/20
SW1(config-if)# isis authentication-type md5 level-1
OSPF Example
SW1(config)# int e2/2
SW1(config-if)# ip ospf authentication message-digest
SW1(config-if)# ip ospf message-digest-key 1 md5 xxxxxxxxxxx
RIP Example
SW1(config)# int e2/8
SW1(config-if)# ip rip authentication mode md5