Messages in this thread | | | Date | Thu, 22 Apr 2004 11:27:05 -0400 (EDT) | From | alex@pilosoft ... | Subject | Re: tcp vulnerability? haven't seen anything on it here... |
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> > > Unless i misunderstood: You need someone/thing to see about 64K > > > packets within a single flow to make the predicition so the attack > > > is succesful. Sure to have access to such capability is to be in a > > > hostile path, no? ;-> > > No, you do not need to see any packet. > > > > Ok, so i misunderstood then. How do you predict the sequences without > seeing any packet? Is there any URL to mentioned paper? You don't - just brute-force the tcp 4-tuple and sequence number. The attack relies on the fact that you don't have to match sequence number exactly, which cuts down on the search-space. (If total search space is 2^32, rwin is 16k, effective attack search space is 2^32/16k). Multiplied by number of ephemeral ports, it becomes *feasible* but still not very likely.
> > Inter-provider BGP is long-lived with close to fixed ports, which is > > why it has caused quite a stir. > > Makes sense. What would be the overall effect though? Route flaps? Yep.
> > Nevertheless, number of packets to kill the session is still *large* > > (under "best-case" for attacker, you need to send 2^30 packets)...
-alex
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