Remote crash of Chaser game <= 1.50

From: Luigi Auriemma (aluigi_at_altervista.org)
Date: 02/03/04

  • Next message: Larry Seltzer: "Hysterical first technical alert from US-CERT"
    Date: Tue, 3 Feb 2004 21:22:51 +0000
    To: bugtraq@securityfocus.com
    
    

    #######################################################################

                                 Luigi Auriemma

    Application: Chaser
                  http://www.chasergame.com
    Versions: <= 1.50
    Platforms: Windows
    Bug: crash (reading of unallocated memory)
    Risk: high
    Exploitation: remote, both server and client are vulnerables
    Date: 03 Feb 2004
    Author: Luigi Auriemma
                  e-mail: aluigi@altervista.org
                  web: http://aluigi.altervista.org

    #######################################################################

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

    #######################################################################

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

    Chaser is a first person shooter developed by Cauldron
    (http://www.cauldron.sk) using the CloakNT game engine.

    #######################################################################

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

    The structure of a Chaser packet is like the following:

    00 00 00 00 00 ff 00 00
       | |
       | size of the data starting at offset 14
       16 bit checksum
       http://aluigi.altervista.org/papers/chaser_crc.h

    The problem is just in the value specifying the size of the data in
    fact if it is too big the game will read all the amount of data
    specified and will reach an unallocated memory zone that will cause an
    exception.
    The following is the instruction that causes the crash in the dedicated
    server 1.50:

    :0050C89F F3A5 rep movsd

    #######################################################################

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

    To test the Chaser server:

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

    The vulnerability affects also the client but naturally the
    dangerousness is really minimale, I have released a proof-of-concept
    also to test this case:

    http://aluigi.altervista.org/poc/chaser-client.zip

    #######################################################################

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

    No fix.
    Cauldron has not replied to my mails.

    #######################################################################

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


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