Horde Framework and Horde IMP /index.php cross site referencing scip AG Vulnerability ID 2456 (08/16/2006) http://www.scip.ch/cgi-bin/smss/showadvf.pl?id=2456 I. INTRODUCTION Horde is an open-source web application framework based on PHP. It offers popular applications, such as the Horde IMP mail client, a groupware and wiki solution. More information is available on the official Horde product web site at the following URL: http://www.horde.org/ II. DESCRIPTION Marc Ruef found several web-based vulnerabilities that were identified in Horde 3.0.4 and verified for all versions prior to 3.1.2 and IMP prior to 4.1.3. Horde is using a frameset to present the output to the user. The top frame has the name horde_menu and the bottom frame has the name horde_main. The main file index.php allows the definition of a source by using the PHP variable $_GET['url']. An attacker might be able to do a cross referencing and inserting malicous web site ressources. This is very useful within technical supported phishing attacks. The legitimate user might not be able to determine the real source of the presentation. And therefore the attacker might be able to intercept the communication and fetch some sensitive data. III. EXPLOITATION Classic script injection techniques within a browser session can be used to exploit this vulnerabilities. [1, 2] A plugin for our open-source exploiting framework "Attack Tool Kit" (ATK) will be published in the near future. [3] IV. IMPACT Because non-authenticated parts of the software are affected too, this vulnerabilities are serious for every secure environment. Non-authenticated users might be able to exploit this flaw to gain elevated privileges (e.g. extracting sensitive cookie information or launch a buffer overflow attack against another web browser). The other parts are affecting authenticated parts. This requires a legitimate user to exploit the vulnerabilities. However, because cross site scripting attacks could be launched from external attackers, these vulnerabilities still become a high risk rating. V. DETECTION Detection of web based attacks requires a specialized web proxy and/or intrusion detection system. Patterns for such a detection are available and easy to implement. VI. SOLUTION The cross site scripting vulnerability (4) has been fixed in CVS HEAD (Juli 2006) and FRAMEWORK_3. The other vulnerabilities were addressed in the current release 3.1.2 and IMP 4.1.3. VII. VENDOR RESPONSE The Horde team has been informed at 07/04/2006 via email to security-at-horde.org. A first response came back on the same day. Several email messages were exchanged to discuss the vulnerabilities and to co-ordinate the disclosure of this advisory. VIII. SOURCES scip AG - Security Consulting Information Process (german) http://www.scip.ch scip AG Vulnerability Database (german) http://www.scip.ch/cgi-bin/smss/showadvf.pl?id=2456 http://www.scip.ch/cgi-bin/smss/showadvf.pl?id=2457 computec.ch document data base (german) http://www.computec.ch/download.php IX. DISCLOSURE TIMELINE 05/15/06 Identification of the vulnerabilities 07/04/06 Informing the Horde team 07/04/06 First reply of the Horde team 08/16/06 Public advisory IX. CREDITS The vulnerabilities were discovered by Marc Ruef. Marc Ruef, scip AG, Zuerich, Switzerland maru-at-scip.ch http://www.scip.ch A1. BIBLIOGRAPHY [1] http://www.computec.ch/download.php?view.812 [2] http://www.computec.ch/download.php?view.808 [3] http://www.computec.ch/projekte/atk/ A2. LEGAL NOTICES Copyright (c) 2006 scip AG, Switzerland. Permission is granted for the re-distribution of this alert. It may not be edited in any way without permission of scip AG. The information in the advisory is believed to be accurate at the time of publishing based on currently available information. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect or consequential loss or damage from use of or reliance on this advisory.