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                             Luigi Auriemma

Application:  Asura engine (network SDK)
              http://www.rebellion.co.uk
Games:        Rogue Trooper                                      <= 1.0
              Prism: Guard Shield                            <= 1.1.1.0
              ...possibly others...
Platforms:    Windows
Bug:          challenge buffer-overflow
Exploitation: remote, versus server (in-game)
Date:         22 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
===============


Asura is a game engine written by Rebellion and used in their games.
Rogue Trooper and Prism are the only two games (as far as I know) which
use the new network protocol which leads to the vulnerability reported
in this advisory, the older games were based on DirectPlay (Judge
Dredd) and Gamespy SDK (Sniper Elite).


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======
2) Bug
======


A buffer-overflow vulnerability is located in the function which
handles the 0xf007 packet used for the challenge B query.
In this function the data passed by the client is copied (without
checks on its length) to a stack buffer of 256 bytes used for sending
the data back to the client, something similar to a ping.


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


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


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


No fix.
Rebellion is one of those vendors which have never replied to my past
mails.


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