Title:
======
Barracuda Web Filter 910 5.0.015 - Multiple Vulnerabilities


Date:
=====
2012-08-02


References:
===========
http://www.vulnerability-lab.com/get_content.php?id=570

Barracuda Networks Security ID: BNSEC-279/BNYF-5533


VL-ID:
=====
570


Common Vulnerability Scoring System:
====================================
4.5


Introduction:
=============
The Barracuda Web Filter is an integrated content filtering, application blocking and malware protection 
solution that is powerful, easy to use and affordable for businesses of all sizes. It enforces Internet 
usage policies by blocking access to Web sites and Internet applications that are not related to business, 
and it easily and completely eliminates spyware and other forms of malware from your organization. No more 
productivity loss trying to repair computers or make computers usable again.

Blocks access to Web sites based on domain, URL pattern, or content category
Blocks downloads based on file type
Blocks applications that access the Internet, including IM, music services, and software update utilities
Integrates with  safe search  filters built into popular images search engines
Provides integrated gateway and desktop spyware protection
Uses Barracuda Web Security Agents compatible with Windows PC’s and Macs to enforce Internet policies on off-network computers

The Barracuda Web Filter combines preventative, reactive, and proactive measures to form a complete Web 
filtering solution. Designed for the enterprise, the Barracuda Web Filter enables you to set up custom policies 
for particular users and groups across customizable time ranges. The Barracuda Web Filter integrates with popular 
LDAP directory servers, such as Microsoft Active Directory, for both authentication and group membership 
information on which to apply custom policies. Sample uses of group policies include:

Restricting access to job board Web sites to only the Human Resources group
Defining separate policies for teachers and students at a school
Enabling compliance officers unrestricted access to the Web for investigation
Providing external instant messaging (e.g., AIM) access only to specific users or groups
Restricting personal Web browsing to non-working hours

For organizations that do not utilize directory servers, policies can be defined for unauthenticated users as a whole, 
locally defined users and groups, or network IP address ranges.

(Copy of the Vendor Homepage: http://www.barracudanetworks.com/ns/products/web-filter-overview.php )


Abstract:
=========
The Vulnerability Lab Research Team discovered multiple Web Vulnerabilities in Barracudas Web Filter Application v5.0.0.015 Appliance Model 910.


Report-Timeline:
================
2012-05-01:  Researcher Notification & Coordination
2012-05-08:  Vendor Notification
2012-06-13:  Vendor Response/Feedback
2012-07-25:  Vendor Fix/Patch
2012-08-02:  Public or Non-Public Disclosure


Status:
========
Published


Affected Products:
==================
Barracuda Networks
Product: Barracuda Web Filter Appliance 910 v5.0.0.015


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


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


Details:
========
Multiple persistent input validation vulnerabilities are detected in the Barracudas Web Filter Application v5.0.0.015 Appliance Model 910. 
The bugs allow remote attackers to implement/inject malicious script code on the application side (persistent). Successful exploitation 
of the vulnerability can lead to session hijacking (manager/admin) or stable (persistent) context manipulation. Exploitation requires 
low user inter action. The vulnerability is located in the NTLM Edit - Host & Domain Name which is bound to the affected vulnerable 
Existing Authentication Services listing.  Another vulnerability is located on the upload key tab in combination with the 
unsanitized short domain name input field + output listing.


Vulnerable Module(s):
        [+] Authentification > New Authentication Service
           [-] NTLM - Server Hostname & Domain Name - Existing Authentication Services

        [+] Authentification > Kerberos > Advanced Settings
           [-] Upload Key Tab File in combination with alternative Short Domain Name

Picture(s):
        ../1.png
        ../2.png


Proof of Concept:
=================
The persistent web vulnerabilities can be exploited by remote attackers with high[-](medium+) user inter action or via 
local low privileged user account with low require user inter action. For demonstration or reproduce ...

Review: NTLM Edit & Listing

<td colspan="2" style="" valign="top" width="285"><input autocomplete="off" id="UPDATE_ntlm_server_hostname:
md5UBwQ8iCjrc1egk1wTV8SEg" name="UPDATE_ntlm_server_hostname:md5UBwQ8iCjrc1egk1wTV8SEg" size="30" value=""
><[PERSISTENT SCRIPT CODE EXECUTION!] <" type="text"><br><div nowrap="" id="host2" style="height: 20px;"> </div></td>

... &

<td colspan="2" style="" valign="top" width="285"><input autocomplete="off" id="UPDATE_ntlm_server_hostname:
md5UBwQ8iCjrc1egk1wTV8SEg" name="UPDATE_ntlm_server_hostname:md5UBwQ8iCjrc1egk1wTV8SEg" size="30" value=""
><[PERSISTENT SCRIPT CODE EXECUTION!]") <" type="text"><br><div nowrap="" id="host2" style="height: 20px;"> </div></td>

Affected:
        [+] Existing Authentication Services via NTLM Edit


Review: Kerberos > Advanced Settings  > Upload Key Tab File in combination with alternative Short Domain Name (Input)

<td style="" valign="top" width="150">Upload keytab:</td>
<td style="" valign="top" width="260">
<div style="position: relative; height: 25px; padding-top: 0px;">
<input disabled="disabled" id="upload_keytab" name="upload_keytab" onchange=" $('tmp_upload_keytab').value=this.value;" 
size="17" style="z-index: 2; opacity: 0; position: absolute; cursor: pointer; text-align: left;" type="file">
<div style="position: absolute; z-index: 1; height: 25px;"><input size="20" id="tmp_upload_keytab">
<input class="new_button disabled_button" disabled="disabled" id="Datei auswählen..." name="Datei auswählen..." 
style="cursor: pointer;" value="Datei auswählen..." type="button"></div></div></td>
      <td style="" valign="top" width="50"><br><div nowrap="" id="kerberos_keytab" style=""> </div></td>
      <td style="" valign="top" width="400"><div id="helpbox"><b class="outlinetop">
          <b class="outline1"></b>
          <b class="outline2"></b>
          <b class="outline3"></b>
          <b class="outline4"></b></b>
          <div id="contents"><div>This keytab file is generated by running the <b>ktpass.exe</b> program from your Windows command line.</div></div>
             <b class="outlinebottom"><b class="outline4"></b><b class="outline3"></b><b class="outline2"></b><b class="outline1"></b></b>
             </div></td>
      <td style="" valign="top" width="10"> </td>
    </tr>
    <tr class="config_module_tr" id="config_module_row_kerberos__8">
      <td valign="top" width="15"> </td>
      <td style="" valign="top" width="150">Short Domain Name:</td>

... &

      <td valign="top" width="15"> </td>
      <td style="" valign="top" width="150">Short Domain Name:</td>
      <td style="" valign="top" width="260"><input autocomplete="off" 
id="UPDATE_new_kerberos_server_short_domain_name" 
name="UPDATE_new_kerberos_server_short_domain_name" 
size="30" type="text"></td>


Affected:
        [+] Kerberos - Existing Authentication Services via Kerberos Advanced Edit - Upload & Short Domain Name


Solution:
=========
Barracuda Networks solved this issue in the Barracuda Networks Webfilter firmware 6.0.0 and up. 
This release is generally available (to all our customers) July 25th, 2012.

The persistent vulnerabilities can be patched by a char restriction of the vulnerable input fields & by parsing the input/output.
Secure the input preview listing of edit ntlm and the output listing in Existing Authentication Services to secure the complete function.


Risk:
=====
The security risk of the both persistent input validation vulnerabilities at the same location are estimated as medium(+).


Credits:
========
Vulnerability Laboratory [Research Team]  -    Benjamin Kunz Mejri (bkm@vulnerability-lab.com)


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===========
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