Cisco CallManager 4.1 Input Validation Vulnerability


Cisco CallManager 4.1 Input Validation Vulnerability scip AG Vulnerability ID 2977 (03/13/2007) http://www.scip.ch/cgi-bin/smss/showadvf.pl?id=2977 I. INTRODUCTION Cisco CallManager, short CCM, is a professional voice-over-IP solution that tracks active components, including among others phones, gateways, conference bridges, transcoding resources and voicemail boxes. II. DESCRIPTION Marc Ruef and Stefan Friedli found a web-based vulnerability that was identified in Cisco CallManager 4.1 and may affect earlier versions as well. The web interface of the application fails to properly santisize data supplied by the search-form before displaying it back to the user. Though several filters are in place to prevent the injection of <script> Tags or action handlers such as "onclick" or "onmouseover", it is possible to inject html-code including common attributes. This allows the embedding of external references, e.g. images or flash resources. The vulnerability also allows an attacker to use the "style"-attribute on any tag to conduct arbitrary web-based attacks. Example: https://example.com/CCMAdmin/serverlist.asp?findBy=servername&match=begins&pattern=<img%20src='http://www.scip.ch/scip.gif'%20style='border:%201px%20solid%20black;'> IV. IMPACT This vulnerability may be exploited by tricking authenticated users into clicking a crafted link in order to conduct arbitrary web-based attacks. V. DETECTION Detection of web based attacks requires a specialized web proxy and/or intrusion detection system. Patterns for detection of basic attacks are available and easy to implement, though they may possibly fail on more sophisticated attacks. VI. SOLUTION Server-side input validation should be improved to prevent the injection of unauthorized code. Cisco has taken appropriate steps regarding this issue, see vendor response (VII) for details. VII. VENDOR RESPONSE A representative of the Cisco Product Security Incident Response Team (PSIRT) stated, that this kind of exploitation is blocked by improvements to the web application firewall used in CallManager. The Cisco PSIRT team has issued a formal security response available at: http://www.cisco.com/warp/public/707/cisco-sr-20070523-ccm.shtml. 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=2977 IX. DISCLOSURE TIMELINE 03/13/07 Identification of the vulnerabilities 03/13/07 Notification of the vendor 03/14/07 Response from Mark-David McLaughlin [marmclau@cisco.com] of the PSIRT 03/19/07 Status Notification by PSIRT 03/28/07 Status Notification by PSIRT 04/18/07 Status Notification by PSIRT 04/20/07 Status Notification by PSIRT 05/02/07 Status Notification by PSIRT 05/05/07 Coordination of public release 05/16/07 Final Vendor Response received 05/23/07 Public Release IX. CREDITS The vulnerabilities were discovered by Marc Ruef and Stefan Friedli. Marc Ruef, scip AG, Zuerich, Switzerland maru-at-scip.ch http://www.scip.ch Stefan Friedli, scip AG, Zuerich, Switzerland stfr-at-scip.ch http://www.scip.ch Thanks to Mark-David McLaughlin (PSIRT) for cooperating. A2. LEGAL NOTICES Copyright (c) 2007 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.