MegaSWF Cross Site Scripting

`Title:  
======  
MegaSWF - Persistant Cross Site Scripting Vulnerability  
  
  
Date:  
=====  
2012-01-12  
  
  
References:  
===========  
http://www.vulnerability-lab.com/get_content.php?id=368  
  
  
VL-ID:  
=====  
368  
  
  
Introduction:  
=============  
Do you create Flash games, Flash animations, or any other type of content saved in the .SWF extension? MegaSWF  
offers you a free, stable .SWF file repository on our high-speed servers.  
  
To take advantage of our service, simply click the Upload button. You can also create an account with MegaSWF  
for more capacity and more functionality. We are always adding new features based on the feedback we get from  
our users.  
  
(Copy of the Vendor Homepage: http://megaswf.com/about)  
  
  
Abstract:  
=========  
A Vulnerability-Lab Reseacher discovered a persistent cross site scripting vulnerability on the MegaSWF website.  
  
  
Report-Timeline:  
================  
2011-12-03: Vendor Notification  
2012-01-12: Public or Non-Public Disclosure  
  
  
Status:  
========  
Published  
  
  
Exploitation-Technique:  
=======================  
Remote  
  
  
Severity:  
=========  
Medium  
  
  
Details:  
========  
A persistent cross site scripting vulnerability is detected on the MegaSwf website service.  
The vulnerability allows an remote attacker with required user inter action to hijack customer sessions via persistent cross site scripting.  
Successful exploitation can result in account steal, client side exploitation or phishing & session hijacking.  
The bug is located on the serve module in-/output of the megaswf service web application.  
  
Vulnerbale Module(s):  
[+] serve  
  
Picture(s):  
../1.png  
  
  
Proof of Concept:  
=================  
The vulnerability can be exploited by remote attacker with required user inter action.  
For demonstration or reproduce ...  
  
PoC:  
[1] Create an URLRequest-Object with a JS-Code like : var alert:URLRequest = new URLRequest("javascript:alert('xss')");  
[2] Publishing the swf in megaswf.com will exploit a persistent xss-vulnerability and run your JS code.  
  
Full code-example that can be used on a frame as actionscript :  
  
import flash.net.URLRequest;  
var alert:URLRequest = new URLRequest("javascript:alert('xss')");  
navigateToURL(alert, "_self");  
  
  
Reference(s) :  
http://megaswf.com/serve/1471214  
  
  
Risk:  
=====  
The security risk of the persistant cross site scripting vulnerability is estimated as medium(+).  
  
  
Credits:  
========  
Vulnerability Research Laboratory - Sebastian Lüdtke (yak0n)  
  
  
Disclaimer:  
===========  
The information provided in this advisory is provided as it is without any warranty. Vulnerability-Lab disclaims all warranties,   
either expressed or implied, including the warranties of merchantability and capability for a particular purpose. Vulnerability-  
Lab or its suppliers are not liable in any case of damage, including direct, indirect, incidental, consequential loss of business   
profits or special damages, even if Vulnerability-Lab or its suppliers have been advised of the possibility of such damages. Some   
states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation   
may not apply. Any modified copy or reproduction, including partially usages, of this file requires authorization from Vulnerability-  
Lab. Permission to electronically redistribute this alert in its unmodified form is granted. All other rights, including the use of   
other media, are reserved by Vulnerability-Lab or its suppliers.  
  
Copyright © 2011|Vulnerability-Lab  
  
--   
Website: www.vulnerability-lab.com ; vuln-lab.com or vuln-db.com  
Contact: [email protected] or [email protected]  
  
`