MODx Installation File XSS Vulnerability

[Andrei Rimsa <rimsa () live com>]

Title: MODx Installation File XSS Vulnerability
Vendor: MODx
Product: MODx CMF
Tested Versions: 1.0.3, 1.0.4
Threat Class: XSS
Severity: Medium
Remote: yes
Local: no
Discovered By: Andrei Rimsa Alvares

===== Description =====

MODx CMF is prone to a XSS vulnerability caused by unsanitized user input data. The bug occurs in a file used in the 
installation process. A description of the affected file is shown below:

--- install/connection.collation.php ----
01: ...
06: $database_collation = $_POST['database_collation'];
...
08: $output = '09: '.$database_collation.'';
...
23: echo $output;
24: ?>
--- install/connection.collation.php ----

The variable $database_collation (line 6) receives user data via http post request and gets propagated to variable 
$output (line 9) without proper sanitization. Later the $output variable is outputted to the page in every program path 
causing the bug (line 23).

===== Impact =====

Malicious java script code can be executed in the context of the affected web site.

===== Proof of Concept =====









===== Workaround =====

Remove all installation files after MODx is successfully installed.

===== Disclosure Timeline =====

June, 16 2010 - Vendor notification.
July, 07 2010 - No vendor reply. Public disclosure.

===== References =====

http://modxcms.com                                        
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