Penetration Testing mailing list archives

Re: [PEN-TEST] IP fragmentation attack


From: "Mitchell, Edward" <ed () THE7THBEER COM>
Date: Sat, 21 Oct 2000 07:25:04 -0700

Packet reassembly is "hard"(apparently some FW and sec. software makers
have different meanings of "hard").  NFR reassembles just fine for
complete inspection, so code to do it is, within a certain set of
parameters, trivial.  Of course, when you have to deal with people like
CheckPoint and Nokia(with IPSO under FW1), the answers range from "Oh, you
don't really NEED to reassemble packets" to "Yes, we can do it at the rate
of 321Mbytes of packets/sec(lame).


I know there are much better qualified
people than me here to
explain > why firewall manufactures are unable to block this kind of thing
effectively, let them do it, thats what they are payed for :)


CF
 - Army of the Twelve Monkeys
 - Agent of a hostile power - John Austin (Detective Chief Inspector
   SO 6 New Scotland Yard, 1996)

--
'Cold Fire, Britains most notorious hacker' Observer, July 1997
'The most recent conviction was that of [Cold Fire] whose On-line
escapades spanned from hacking into educational sites to more
sinister activities such as tapping into industrial and United
States military sites.' DC Paul Cox, SO6 Scotland Yard CCU



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