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                             Luigi Auriemma

Application:  Skulltag
              http://www.skulltag.com
Versions:     <= 0.97d-beta4.1
Platforms:    Windows and Linux
Bug:          heap-overflow
Exploitation: remote, versus server
Date:         23 Aug 2007
Author:       Luigi Auriemma
              e-mail: aluigi@autistici.org
              web:    aluigi.org


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1) Introduction
2) Bug
3) The Code
4) Fix


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===============
1) Introduction
===============


Skulltag is a well known and played Doom engine mainly based on Zdoom
(but not open source as it) and focused on online gaming.


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2) Bug
======


The game is vulnerable to a heap overflow located in the function which
performs the huffman decompression of the incoming packets, allowing
possible malicious code execution through a single UDP packet.


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===========
3) The Code
===========


http://aluigi.org/poc/skulltaghof.zip


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======
4) Fix
======


No fix.
Developers have not been contacted since one year ago the format string
vulnerability I reported to them was handled as a normal bug and the
patch was released some months after my advisory.


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--- 
Luigi Auriemma
http://aluigi.org
http://mirror.aluigi.org