Bill Stewart wrote:
At 02:17 PM 9/16/2004, Joe Touch wrote:
Ian Grigg wrote:
On the backbone, between BGP peers, one would have thought that there are relatively few attackers, as the staff are highly trusted and the wires are hard to access - hence no active attacks going on and only some passive eavesdropping attacks. Also, anyone setting up BGP routing knows the other party, so there is a prior relationship.
My understanding of the attacks this past spring is that: a) they were indeed on the backbone BGP peers b) that those peers had avoided setting up preshared keys or getting mutually-authenticatable certificates because of the configuration overhead (small on a per-pair basis, but may be large in aggregate)
The interesting attacks were a sequence-number guessing attack using forged TCP RST packets, which tell the TCP session to tear down, therefore dropping the BGP connection (typically between two ISPs). The attackers didn't need to be trusted backbone routers - they could be randoms anywhere on the Internet. BGP authentication doesn't actually help this problem, because the attack simply kills the connection at a TCP layer rather than lying to the BGP application.
FWIW, the other system we were referring to - TCP-MD5 - works at the TCP layer. It rejects packets within TCP, before any further TCP processing, that don't match the MD5 hash. It isn't BGP authentication.
This is why I refer to it as TCP-MD5 rather than BGP-MD5, even though the latter is more common.
Joe
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