Barracuda Cloud Series - Filter Bypass Vulnerability (ID 731)

[Vulnerability Lab <research () vulnerability-lab com>]

Document Title:
===============
Barracuda Cloud Series - Filter Bypass Vulnerability (ID 731)


References (Source):
====================
http://www.vulnerability-lab.com/get_content.php?id=754

Barracuda Networks Security ID (BNSEC): 731


Release Date:
=============
2015-01-19


Vulnerability Laboratory ID (VL-ID):
====================================
754


Common Vulnerability Scoring System:
====================================
4.1


Abstract Advisory Information:
==============================
The Vulnerability Laboratory Research Team discovered a filter bypass vulnerability in the official Barracuda Cloud 
Series Products.


Vulnerability Disclosure Timeline:
==================================
2015-01-19:     Public Disclosure (Vulnerability Laboratory)


Discovery Status:
=================
Published


Affected Product(s):
====================
Barracuda Networks
Product: Cloud Control Center 2014 Q2


Exploitation Technique:
=======================
Remote


Severity Level:
===============
Medium


Technical Details & Description:
================================
A filter bypass vulnerability has been discovered in the official Barracuda Networks Cloud Series Appliance 
Applications 2014-Q1.
The filter bypass issue allows an attacker to bypass the secure filter validation of the service to execute malicious 
script codes. 

The barracuda filter blocks for example standard iframes, scripts and other invalid code context: The cloud service has 
a own exception-handling 
to parse or encode malicious injected web context. The mechanism filters the first request and sanitizes the output in 
every input field.

During a pentest we injected a standard iframe to check and provoke the validation. The frame got blocked! In the next 
step the attacker splits (%20%20%20) 
the request and injects at the end an onload frame to an external malicious source. The second iframe with the onload 
alert executes the script codes after 
the validation encoded only the first script code tag. The second script code tag can bypass the applicance filter 
mechanism and executes in the web context 
of affected modules. The secure validation does not recognize a splitted request which results in client-side and 
application-side script code execution in 
the cloud series products.

The security risk of the filter bypass vulnerability is estimated as medium and the cvss (common vulnerability scoring 
system) count is 4.1 (medium). 
Exploitation of the filter bypass vulnerability requires a low privileged application user account with restricted 
access and low user interaction. 
Successful exploitation of the vulnerability results in session hijacking, persistent phishing, persistent external 
redirects and persistent manipulation 
of affected or connected module context.

Vulnerable Request Method(s):
                                [+] POST & GET


Proof of Concept (PoC):
=======================
The filter bypass web vulnerability can be exploited by local privileged user accounts and remote attackers with low or 
medium user interaction. 
For security demonstration or to reproduce the security vulnerability follow the provided information and steps below 
to continue.

PoC: 
<iframe src=a>%20%20%20%20\"><iframe src=http://vuln-lab.com onload=alert("VL") <

PoC: 
<script 
language=JavaScript>m='%3Ciframe%20src%3Da%3E%2520%2520%2520%2520%5C%22%3E%3Ciframe%20src%3Dhttp%3A//vuln-lab.com%20onload%3Dalert%28%22VL%22%29%20%3C';d=unescape(m);document.write(d);</script>


Solution - Fix & Patch:
=======================
The issue can be patched by a secure validation of the full message input body context of any input or request method 
attempt.
Ensure that the validaton does not only encode the first injected script code since a empty char arrives. Filter all 
web context 
that runs through the requesting procedure and parse separatly to prevent script code injection attacks.

Note: Barracuda Networks patched the vulnerability and acknowledged the researcher. Updates are available in Barracuda 
Labs and the Customer Service.


Security Risk:
==============
The security risk of the filter bypass web vulnerability in the barracuda cloud product series is estimated as medium. 
(CVSS 4.1)


Credits & Authors:
==================
Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri (bkm () evolution-sec com) [www.vulnerability-lab.com]


Disclaimer & Information:
=========================
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. We do not approve or encourage anybody 
to break any vendor licenses, 
policies, deface websites, hack into databases or trade with fraud/stolen material.

Domains:    www.vulnerability-lab.com           - www.vuln-lab.com                                      - 
www.evolution-sec.com
Contact:    admin () vulnerability-lab com      - research () vulnerability-lab com                     - admin () 
evolution-sec com
Section:    magazine.vulnerability-db.com       - vulnerability-lab.com/contact.php                     - 
evolution-sec.com/contact
Social:     twitter.com/#!/vuln_lab             - facebook.com/VulnerabilityLab                         - 
youtube.com/user/vulnerability0lab
Feeds:      vulnerability-lab.com/rss/rss.php   - vulnerability-lab.com/rss/rss_upcoming.php            - 
vulnerability-lab.com/rss/rss_news.php
Programs:   vulnerability-lab.com/submit.php    - vulnerability-lab.com/list-of-bug-bounty-programs.php - 
vulnerability-lab.com/register/

Any modified copy or reproduction, including partially usages, of this file requires authorization from Vulnerability 
Laboratory. 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 Research Team or its suppliers. All pictures, texts, advisories, source code, videos and other 
information on this website 
is trademark of vulnerability-lab team & the specific authors or managers. To record, list (feed), modify, use or edit 
our material contact 
(admin () vulnerability-lab com or research () vulnerability-lab com) to get a permission.

                                Copyright © 2015 | Vulnerability Laboratory - [Evolution Security GmbH]™

-- 
VULNERABILITY LABORATORY - RESEARCH TEAM
SERVICE: www.vulnerability-lab.com
CONTACT: research () vulnerability-lab com
PGP KEY: http://www.vulnerability-lab.com/keys/admin () vulnerability-lab com%280x198E9928%29.txt



_______________________________________________
Sent through the Full Disclosure mailing list
https://nmap.org/mailman/listinfo/fulldisclosure
Web Archives & RSS: http://seclists.org/fulldisclosure/