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[Full-disclosure] Countslide alphanumeric GetPC

From: Berend-Jan Wever <berendjanwever_at_nospam>
Date: Sat Jan 02 2010 - 20:48:40 GMT
To: Full-disclosure <full-disclosure@lists.grok.org.uk>


One limitation of most alphanumeric shellcode decoders, including those in * ALPHA2<http://skypher.com/wiki/index.php/Hacking/Shellcode/Alphanumeric/ALPHA2>
* and the soon-to-be-released

*ALPHA3<http://skypher.com/wiki/index.php/Hacking/Shellcode/Alphanumeric/ALPHA3>
* is that they need to know where they are located in memory in order to
decode themselves and run correctly. This makes using a *nopslide* hard in most circumstances, because you mostly only need a *nopslide* if you do not know exactly where your shellcode is in memory to begin with.

I've developed a way to get around this problem, which I've described in more detail here:
http://skypher.com/index.php/2010/01/02/countslide-alphanumeric-getpc/

ALPHA3 has support for generating working alphanumeric shellcode with nopslides using this technique. I'm currently working on getting the rest of its code into releasable shape.

Cheers,
SkyLined
 <http://skypher.com/index.php/2010/01/02/countslide-alphanumeric-getpc/> Berend-Jan Wever <berendjanwever@gmail.com> http://skypher.com/SkyLined



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