From: Crispin Cowan (crispinimmunix.com)
Date: Fri Aug 15 2003 - 13:00:04 CDT

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Florian Weimer wrote:

>Crispin Cowan <crispinimmunix.com> writes:
>
>
>>Thanks to Snax and the Shmoo for a better tag line: It's not the Size
>>of the Buffer, it's the Address of the Pointer
>>
>>
>This is not true. There are buffer overflow exploits which do not
>modify pointers, but other objects. The most prominent example is
>probably the "c c c c c..." exploit for the Solaris /bin/login
>vulnerability.
>
Please address technical commentary to the paper (which addresses this
point) and not to the cute tag line.

WRT this point: correct, PointGuard does not stop all buffer overflows.
IMHO it *nearly* stops all shell code. To bypass PointGuard, you have to
corrupt the logic of the program itself to get its own code to do what
you want; you can't readily generate a jump to arbitrary code.

Caveat: I can't prove the above, and someone may generate a bypass. But
I don't know of one.

Crispin

--
Crispin Cowan, Ph.D. http://immunix.com/~crispin/
Chief Scientist, Immunix http://immunix.com
            http://www.immunix.com/shop/

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