XSS vulnerability in CompuCMS

[advisory () htbridge ch]

Vulnerability ID: HTB22581
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_compucms_1.html
Product: CompuCMS  
Vendor: CompuSoft A/S ( http://www.compusoft.dk/ ) 
Vulnerable Version: Current at 06.08.2010 and Probably Prior Versions
Vendor Notification: 09 August 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 "index.asp" script to properly sanitize user-supplied input in "sprog" 
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/index.asp?mode=for!forside!gb&sprog=gb'";><script>alert(document.cookie)</script>