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Group-Office 4.0.71 Cleartext Credentials Stored in Cookies


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:
  • Vendor notified: 19/07/2012
  • Vendor fixed: 25/07/2012
  • Credit: Chris Cooper and Joseph Sheridan of Reaction Information Security

About ReactionIS

Reaction Information Security is a leading independent pen test consultancy specialising in delivering the highest quality services including network pen testing and web application security testing. As a CESG CHECK Service Provider we are authorised to carry out penetration testing on classified government networks.

Affected Products

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


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.


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.


Upgrade to Group-Office community 4.0.73.


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 current page for any updates.

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