The Cisco ACI must be configured to use encryption for routing protocol authentication.

A rogue router could send a fictitious routing update to convince a site's perimeter router 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 router 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 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.

To configure a Cisco ACI to use encryption for routing protocol authentication, set up a "pre-shared key" (PSK) on the APIC, which will then be used to generate encryption keys for the routing protocol authentication process, essentially encrypting the authentication messages exchanged between switches within the fabric. This feature is typically referred to as "CloudSec Encryption" within the ACI platform.