Listen and Whisper: Security Mechanisms for BGP

BGP, the current inter-domain routing protocol, assumes that the routing information propagated by authenticated routers is correct. This assumption renders the current infrastructure vulnerable to both accidental misconfigurations and deliberate attacks. To reduce this vulnerability, we present a combination of two mechanisms: Listen and Whisper. Listen passively probes the data plane and checks whether the underlying routes to different destinations work. Whisper uses cryptographic functions along with routing redundancy to detect bogus route advertisements in the control plane. These mechanisms are easily deployable, and do not rely on either a public key infrastructure or a central authority like ICANN.

The combination of Listen and Whisper eliminates a large number of problems due to router misconfigurations, and restricts (though not eliminates) the damage that deliberate attackers can cause. Moreover, these mechanisms can detect and contain isolated adversaries that propagate even a few invalid route announcements. Colluding adversaries pose a more stringent challenge, and we propose simple changes to the BGP policy mechanism to limit the damage colluding adversaries can cause. We demonstrate the utility of Listen and Whisper through real-world deployment, measurements and empirical analysis. For example, a randomly placed isolated adversary, in the worst case can affect reachability to only 10% of the nodes.