SEC Consult Vulnerability Lab Security Advisory < 20130417-0 >
=======================================================================
              title: Multiple vulnerabilities in Sosci Survey
            product: Sosci Survey
 vulnerable version: <2.3.04a
      fixed version: 2.3.04a
             impact: Critical
           homepage: https://www.soscisurvey.de
              found: 2012-06-18
                 by: T. Lazauninkas, V. Paulikas
                     SEC Consult Vulnerability Lab
                     https://www.sec-consult.com
=======================================================================

Vendor description:
-------------------
SoSci Survey provides a non-comercial survey service, letting anyone to create and
share surveys for collecting data in a purpose of scientific research. It is a
flexible and efficient tool as it lets you to create a very customizable survey,
including active content (javascript) and PHP code.

https://www.soscisurvey.de/


Vulnerability overview/description:
-----------------------------------
1) Authorization Issues
   The web application fails to validate authorization for
   certain requests. This allows unauthorized users to access private messages
   that belong to other users.

2) Cross-Site Scripting
   The web application is prone to persistent and reflected Cross-Site Scripting
   attacks. The vulnerability can be used to include HTML or JavaScript
   code to the affected web page. The code is executed in the browser of
   users if they visit the manipulated site. The vulnerability can be used
   to change the contents of the displayed site, redirect to other sites
   or steal user credentials. Additionally, Portal users are potential
   victims of browser exploits and JavaScript Trojans.

3) Remote command execution
   Due to insufficient input validation, the web application fails to properly
   filter dangerous PHP code passed from the user side. This leads to OS command
   execution with the privileges of the web server. By exploiting this
   vulnerability, an attacker can read/write files, open connections, etc. posing
   a critical security risk.


Proof of concept:
-----------------

1) In the user profile, users are able to send and receive private messages to
   each other. This also includes the administrative users. By modifying one of the
   vulnerable script's parameters an attacker can read the messages of other users.
   A proof of concept is provided below:

   https://www.example.com/admin/index.php?o=account&a=message.reply&id=[msg_id]

   By iterating between the integer parameter's id value, an attacker is able to exploit
   this vulnerability.

2) If an invalid id value is passed to the receiver.edit module, which is handled by
   the index.php script, its contents is reflected to the user without proper filtering.
   This leads to javascript execution in the web browser. This issue can be easily exploited
   by navigating to the folowing URL:


https://www.example.com/admin/index.php?o=panel&a=receiver.edit&id=<script>alert(document.cookie)</script>

   An alert with the user's session cookie will be shown.

   Persistent Cross-Site scripting was identified in the private messaging module. It was
   discovered, that [subject, title, firstName, surname, content] parameters are
   vulnerable to persistent Cross-Site scripting as they are saved and later shown
   without proper filtering. A sample request is provided below:

    POST /admin/index.php HTTP/1.1
    Host: www.example.com
    [...]
    rec-name=some_name&subject=%3Cscript%3Ealert%28document.cookie%29%3C%2Fscript%3E
    &message=asd%3Cscript%3Ealert%28document.cookie%29%3C%2Fscript%3E&o=account
    &a=message.send&reference=

   Many parameters are vulnerable to reflected Cross-Site Scripting vulnerabilities:

   URL:
        https://www.example.com/admin/index.php

        Parameters:
            replace[0-24]
            search[0-24]
            id
            O
            Referer (header)

   URL:
        https://www.example.com/admin/ajax.feedback.php

        Parameters:
            dat_type

3) When creating a new survey it is possible to include PHP code. Despite that the web
   application is filtering most of the dangerous PHP functions, that would allow to execute OS
   commands, it is still possible to execute arbitrary commands by using the provided code below:

   print `id`;

   The above code, when executed, prints out the system id of the current user. This could be further
   exploited by an attacker for accessing the local file system, creating malicious files, opening
   remote conections, etc.


Vulnerable / tested versions:
-----------------------------
Pre-installed version of SoSci Survey, hosted on www.soscisurvey.de domain, was
tested. It was not possible to determine an exact version of the installed software.


Vendor contact timeline:
------------------------
2013-01-29: Contacted vendor through info@soscisurvey.de
2013-01-29: Initial vendor response - issues will be verified
2013-03-29: Status request sent
2013-03-29: Vendor response: Security update 2.3.04a is available
2013-04-17: SEC Consult releases coordinated security advisory


Solution:
---------
Update to version 2.3.04a.


Workaround:
-----------


Advisory URL:
-------------
https://www.sec-consult.com/en/Vulnerability-Lab/Advisories.htm


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EOF T. Lazauninkas, V. Paulikas / @2013