====================================================================== Secunia Research 01/08/2012 - Citrix Access Gateway Plug-in for Windows - - "nsepacom" ActiveX Integer Overflow Vulnerability - ====================================================================== Table of Contents Affected Software....................................................1 Severity.............................................................2 Vendor's Description of Software.....................................3 Description of Vulnerability.........................................4 Solution.............................................................5 Time Table...........................................................6 Credits..............................................................7 References...........................................................8 About Secunia........................................................9 Verification........................................................10 ====================================================================== 1) Affected Software * Citrix Access Gateway Plug-in for Windows version 9.3.49.5. NOTE: Other versions may also be affected. ====================================================================== 2) Severity Rating: Highly critical Impact: System access Where: From remote ====================================================================== 3) Vendor's Description of Software "Citrix Access Gateway Plug-in is client software for Windows XP and Windows Vista (32-bit) that enables secure connectivity through Access Gateway, Enterprise Edition." Product Link: http://www.citrix.com/site/ss/downloads/details.asp?downloadId= 1535878&productId=15005 ====================================================================== 4) Description of Vulnerability Secunia Research has discovered a vulnerability in Citrix Access Gateway Plug-in for Windows, which can be exploited by malicious people to compromise a user's system. The vulnerability is caused by an integer overflow error in the nsepacom ActiveX control (nsepa.exe) when processing HTTP responses based on the request via the "StartEpa()" method. This can be exploited to cause a heap-based buffer overflow via a specially crafted "Content-Length" HTTP response header. Successful exploitation may allow execution of arbitrary code. ====================================================================== 5) Solution No official solution is currently available. ====================================================================== 6) Time Table 19/07/2011 - Vendor notified. 21/07/2011 - Vendor response. 20/01/2012 - Requested status update. 08/02/2012 - Vendor response, fix not scheduled. 09/05/2012 - Requested status update. 09/05/2012 - Vendor response, fix scheduled for June. 03/07/2012 - Requested status update. 21/07/2012 - Vendor response, fix delayed. 01/08/2012 - Public disclosure. ====================================================================== 7) Credits Discovered by Dmitriy Pletnev, Secunia Research. ====================================================================== 8) References The Common Vulnerabilities and Exposures (CVE) project has assigned CVE-2011-2593 for the vulnerability. ====================================================================== 9) About Secunia Secunia offers vulnerability management solutions to corporate customers with verified and reliable vulnerability intelligence relevant to their specific system configuration: http://secunia.com/advisories/business_solutions/ Secunia also provides a publicly accessible and comprehensive advisory database as a service to the security community and private individuals, who are interested in or concerned about IT-security. http://secunia.com/advisories/ Secunia believes that it is important to support the community and to do active vulnerability research in order to aid improving the security and reliability of software in general: http://secunia.com/secunia_research/ Secunia regularly hires new skilled team members. Check the URL below to see currently vacant positions: http://secunia.com/corporate/jobs/ Secunia offers a FREE mailing list called Secunia Security Advisories: http://secunia.com/advisories/mailing_lists/ ====================================================================== 10) Verification Please verify this advisory by visiting the Secunia website: http://secunia.com/secunia_research/2012-26/ Complete list of vulnerability reports published by Secunia Research: http://secunia.com/secunia_research/ ======================================================================