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                             Luigi Auriemma

Application:  Raknet network library
              http://www.rakkarsoft.com
Versions:     <= 2.33 (before 30 May 2005)
              the bug has been introduced in some recent updates but
              is not known what is the exact first vulnerable version
Platforms:    Windows and Unix
Bug:          server termination and endless loop
Exploitation: remote, versus server
Date:         05 June 2005
Author:       Luigi Auriemma
              e-mail: aluigi@autistici.org
              web:    http://aluigi.altervista.org


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


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


Raknet is a multi-license (GPL, shareware and commercial) network
library for games developed by Rakkarsoft.
It has been used in many open and closed source games like those
developed by nFusion (http://www.n-fusion.com).
Just the recent game of this software house, Elite Warriors: Vietnam
(http://www.n-fusion.com/nFusion/ewvstory.html), released in March 2005
is one of the vulnerable games (versions <= 1.03).
Anyway the older games developed by nFusion are not vulnerable since
they use older versions of the library that don't contain the bug.


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


An UDP packet of 0 bytes is able to freeze the game server.
The problem is that when an empty packet is received the server should
close the socket and return to the main menu (the first bug) but before
doing that it enters in an endless loop that executes Sleep(10) until
the main thread is active (but never terminates).


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


http://aluigi.altervista.org/poc/rakzero.zip


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4) Fix
======


Version 2.33 (05/30/2005).
The version number has not been changed so be sure to have the patched
version released the 30 May 2005 or later.


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