potential new IETF WG on anonymous IPSec

[Joe Touch]

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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