OSEC

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Re: A new TCP/IP blind data injection technique?

From: Michal Zalewski (lcamtufghettot.org)
Date: Fri Dec 12 2003 - 11:24:00 CST

> I suspect that in these cases the RSTs may be coming from firewalls
> rather than end-hosts. It would be more impressive and surprising if
> one ever got a SYN-ACK in response.

Not really. A variant of the same test addressed to common ports such as
139 resulted in four SYN+ACKs coming back, compared to 50 SYN+ACKs when
the checksum was correct - which is roughly similar to the previous
figure. Quite surprisingly, some of this comes from what seems to be
Windows XP SP1 - but maybe an intermediate device rewrites the packet
instead.

--
------------------------- bash$ :(){ :|:&};: --
 Michal Zalewski * [http://lcamtuf.coredump.cx]
    Did you know that clones never use mirrors?
--------------------------- 2003-12-12 18:18 --

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