XSS vulnerability in WebPress

[advisory@xxxxxxxxxxx]

Vulnerability ID: HTB22480
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_webpress_2.html
Product: WebPress
Vendor: YWP ( http://www.goywp.com/ ) 
Vulnerable Version: Current at 01.07.2010 and Probably Prior Versions
Vendor Notification: 01 July 2010 
Vulnerability Type: XSS (Cross Site Scripting)
Status: Not Fixed, Vendor Alerted, Awaiting Vendor Response
Risk level: Medium 
Credit: High-Tech Bridge SA - Ethical Hacking & Penetration Testing 
(http://www.htbridge.ch/) 

Vulnerability Details:
User can execute arbitrary JavaScript code within the vulnerable application.

The vulnerability exists due to failure in the 
"admin_page_sidemenu_blocks_action.php" script to properly sanitize 
user-supplied input in "id_num_mod" variable. Successful exploitation of this 
vulnerability could result in a compromise of the application, theft of 
cookie-based authentication credentials, disclosure or modification of 
sensitive data.

An attacker can use browser to exploit this vulnerability. The following PoC is 
available:


http://host/path/_system/menus/sidemenu_blocks/_pages/admin_page_sidemenu_blocks_action.php?id_num_mod=1%27%22%3E%3Cscript%3Ealert%28document.cookie%29%3C/script%3Edcf&submit_action=Edit