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                         Luigi Auriemma

Application: Crysis
http://www.ea.com/crysis/home.jsp
Versions: <= 1.21 (1.1.1.6156 showed as gamever)
Platforms: Windows
Bug: NULL pointer in the HTTP/XML-RPC service
Exploitation: remote, versus server
Date: 16 Jun 2008
Author: Luigi Auriemma
e-mail: [email protected]
web: aluigi.org

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

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1) Introduction

Crysis is a recent FPS game developed by Crytek (http://www.crytek.com)
and released at November 2007.
This game is well known for being a "computer killer" due to its high
hardware requirements but also for having various problems with
cheaters.

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2) Bug

Crysis has a small internal HTTP/XML-RPC server which must be activated
with the http_startserver command (manually or through server.cfg) and
allows to receive rcon commands.

This service works on port 80 if no port is specified but usually the
admins choose a custom port or just the same of the game (64087, the
service is easily distinguishable due to the "Bad Request" title
visible with a web browser).

If an attacker uses an HTTP request with a total length major than 4096
bytes the server will crash due to a NULL pointer.

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3) The Code

http://aluigi.org/poc/dontcrysis.txt

nc SERVER HTTPPORT -v -v < dontcrysis.txt

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4) Fix

No fix

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Luigi Auriemma
http://aluigi.org