/------------------------------------------------------\
| Group-Office Cleartext Credentials Stored in Cookies |
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Summary
=======

Group-Office 4.0.71 was found to display a behaviour that could potentially
expose a user's username and cleartext password to third-parties. Under
certain circumstances the application would return two cookies, one
containing the user's username and the other their cleartext password. These
cookies would then be returned to the server with each request to the
application.

CVE number: CVE-2012-4239
Impact: Medium
Vendor homepage: http://www.group-office.com/
Vendor notified: 19/07/2012
Vendor fixed: 25/07/2012
Credit: Chris Cooper and Joseph Sheridan of Reaction Information Security
(http://www.reactionpenetrationtesting.co.uk/)

This advisory is posted at:

http://www.reactionpenetrationtesting.co.uk/group-office-cookies.html


Affected Products
======== ========

Confirmed in Group-Office community 4.0.71. Other versions may also be
affected.


Details
=======

When logging into the application, if a user ticks the 'Remember my login on
this computer until I press logout' box, and then successfully logs into the
application, two cookies ('GO_UN' and 'GO_PW') are returned. These cookies
contain the user's username and cleartext password respectively.

The cookies are set with the 'HttpOnly' flag which would significantly
reduce the chances of their disclosure during a cross-site scripting attack.
However, the application does not enforce a secure channel by default, and
the offending cookies are not set with the 'Secure' flag.


Impact
======

Once these cookies are stored, the user's username and password could be
transferred over an insecure HTTP connection, increasing the liklihood that
an attacker might be able to intercept the credentials and access the
application.

Furthermore, the cleartext credentials will be stored on the computer which
makes them more easily accessible to an attacker with access to the machine.
This significantly lowers the difficulty of exploitation.


Solution
========

Upgrade to Group-Office community 4.0.73.


Distribution
============

In addition to posting on the website, a text version of this notice has
been posted to the following e-mail and Usenet news recipients.

* bugtraq () securityfocus com
* full-disclosure () lists grok org uk

Future updates of this advisory, if any, will be placed on the ReactionIS
corporate website, but may or may not be actively announced on mailing lists
or newsgroups. Users concerned about this problem are encouraged to check
the URL below for any updates:



http://www.reactionpenetrationtesting.co.uk/group-office-cookies.html

============================================================================
==

Reaction Information Security 
Lombard House Business Centre,
Suite 117,
12-17 Upper Bridge Street,
Canterbury, Kent, CT1 2NF

Phone: +44 (0)1227 785050
Email: research () reactionis {dot} co {dot} uk
Web: http://www.reactionpenetrationtesting.co.uk