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                         Luigi Auriemma

Application: Live for Speed
http://www.lfs.net
Versions: <= 0.5X10
Platforms: Windows
Bugs: A] nickname buffer-overflow
B] partial track buffer-overflow
C] NULL pointer access in internet/hidden S1/S2 servers
D] memcpy() NULL pointer in internet/hidden S1/S2 servers
Exploitation: remote, versus server
A] demo/S1/S2 in-game
B] demo/S1/S2 in-game
C] S1/S2 (internet/hidden)
D] S1/S2 (internet/hidden)
Date: 14 Aug 2007
Author: Luigi Auriemma
e-mail: [email protected]
web: aluigi.org

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

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1) Introduction

Live for Speed (LFS) is one of the most known and cool car racing
simulators available since you can do a lot of things: races,
autocross, drifting, drag races and a parking too.

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2) Bugs

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A] nickname buffer-overflow

A buffer-overflow vulnerability is located in the portion of code which
handles the client's nickname from packets with ID 3.
This packet must contain the following NULL terminated strings:

24 bytes for the nickname
8 bytes for the car's plate
16 bytes for other data
16 bytes for the helmet

For exploiting the bug it's enough to set a nickname longer than its
needed size overwriting the other fields after it in the packet.

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B] partial track buffer-overflow

Another buffer-overflow is exploitable through the packets with ID 10
but this time doesn't seem possible to use it for executing remote
code because the return address is overwritten by a fixed string of the
server.

In short when the user requests a track which is not available on the
host, the server calls:

sprintf(buff, "%s is not enabled on this host", client_track);

using a destination buffer enough big to avoid the controlling of the
return address but not enough for avoiding a crash.

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C] NULL pointer access in internet/hidden S1/S2 servers

The S1 and S2 servers which run in internet (so visible on the master
server) or hidden mode are vulnerable to a crash attack caused by the
access to a NULL pointer.
The problem is exploitable through a packet containing a byte 0x00 at
the data offset 23 of the pre-login packet with ID 3.
demo and LAN servers are not vulnerable.

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D] memcpy() NULL pointer in internet/hidden S1/S2 servers

The S1 and S2 servers which run in internet (so visible on the master
server) or hidden mode are vulnerable to a crash attack caused by the
calling of memcpy() with a NULL source (in reality it's NULL + 12).
The problem seems caused by the absence of one or more needed strings
in the pre-login packet with ID 5.
demo and LAN servers are not vulnerable.

Resuming:
Both the bugs A and B are in-game so the attacker must have access to
the server like knowing its password if it's protected or being not
banned.
Bugs C and D instead work versus any server except demo and LAN servers
and are not in-game so any attacker can crash any server, password
protected too.

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3) The Code

with the following tool the bugs A and B can be tested only versus the
demo server:

http://aluigi.org/fakep/lfsfp.zip

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4) Fix

The only thing that the developers have been able to tell me is that
the bugs will be fixed in Patch Y (yes I have asked for a release date
but they don't know it)… that's really stupid since a quick fix was
the best choice moreover considering the auto-patching system of the
game.

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

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