Has BGP routing security failed (yet)?
▼ In the thorough style we've come to expect from him, Geoff Huston tries to answer the question Is Secured Routing a Market Failure? Please read about the market aspect (and the limitations imposed on the IETF by big router vendors) in that article. His final conclusion is broader, through:
But mostly it's a failure because it does not deliver. Security solutions that offer only a thin veneer of the appearance of improvement while offering little in the way of improved defence against determined attack are perhaps worse than a placebo.
20 years ago I went to my first IETF meeting and there I learned about S-BGP and soBGP. It would take another almost ten years for RPKI to be standardized and fifteen years for the BGPSEC specification (which is largely S-BGP with the RPKI functionality removed) to be published. RPKI is gaining some traction but hasn't been able to stop at least some determined attackers. There are no production level implementations of BGPSEC after five years.
So why is that? True, if people would be prepared to pay extra for secure routing, we'd have it by now.
But I think the bigger issue is failure to understand the problem.
Looking at the valley-free model, we can observe that the right hand part of the network hierarchy is trusted by the sender of the routing updates / receiver of the packets, while the left hand side is trusted by the receiver of the routing updates / sender of the packets.
This hierarchy is pretty flat, so there's usually only a handful of networks on each side. So telling the world that those are networks you trust should be something we can do reasonably efficiently. Then, the only thing is to make sure that there are no network hops in the path that aren't trusted by either side.
Earlier this year, RFC 9234 "Route Leak Prevention and Detection Using Roles in UPDATE and OPEN Messages" was published. This adds some information to BGP that lets it detect paths that aren't valley-free. The nice thing about this mechanism is that it protects two networks that implement the mechanism against mistakes made by networks that don't implement the mechanism.
We still need better mechanisms to thwart determined, purposeful attackers, but the good news is that we've made life a lot harder for those already. So even though we're not there yet when it comes to secured routing, it's not so much that we've failed, but that we are taking too much time to succeed.
Permalink - posted 2022-12-13