Secunia Research: Citrix Access Gateway Plug-in for Windows nsepacom ActiveX Control Buffer Overflow

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                 Secunia Research 01/08/2012

         - Citrix Access Gateway Plug-in for Windows -
     - "nsepacom" ActiveX Buffer Overflow Vulnerability -

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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

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1) Affected Software

• Citrix Access Gateway Plug-in for Windows version 9.3.49.5.

NOTE: Other versions may also be affected.

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2) Severity

Rating: Highly critical
Impact: System access
Where: From remote

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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

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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 a boundary 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 an overly long "CSEC" HTTP
response header.

Successful exploitation allows execution of arbitrary code.

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5) Solution

No official solution is currently available.

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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.

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7) Credits

Discovered by Dmitriy Pletnev, Secunia Research.

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8) References

The Common Vulnerabilities and Exposures (CVE) project has assigned
CVE-2011-2592 for the vulnerability.

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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
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http://secunia.com/corporate/jobs/

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http://secunia.com/advisories/mailing_lists/

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10) Verification

Please verify this advisory by visiting the Secunia website:
http://secunia.com/secunia_research/2012-27/

Complete list of vulnerability reports published by Secunia Research:
http://secunia.com/secunia_research/

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