Boastmachine Cross Site Scripting Vulnerability

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Advisory      : Cross Site Scripting in Boastmachine (http://boastology.com/)
Release Date  : 17/05/2005
Last Modified : 17/05/2005
Author        : Yunus Emre Yilmaz ( http://yns.zaxaz.com)
Application   : BoastMachine v3.1 ( maybe older versions)
Risk          : High

Problem : Form action values in admin.php and index.php (maybe other pages) 
isn't properly sanitized before being returned to page.Form action value
is otomatically coming from $_SERVER["PHP_SELF"];.And This is changeable from 
query string.

If I access page like admin.php/XSS $_SERVER["PHP_SELF"] returns as 
admin.php/XSS.So , an attacker basicly inject malicious
HTML/JS codes into page.

Proof Of Concept : admin.php/"><script>alert('xss')</script>

Solution : Edit the source code , and change it $_SERVER["SCRIPT_NAME"] or 
filter it before printing in page.

Original Advisory : http://yns.zaxaz.com/advisories/bostmachine.txt