Citrix Access Gateway Plug-in for Windows nsepacom ActiveX Control Vulnerabilities

SA45299

CVE-2011-2592, CVE-2011-2593

01 Aug 2012

10 Aug 2012

Highly Critical

Vendor Patch

Citrix Access Gateway Plug-in for Windows 9.x
Citrix nsepacom ActiveX Control 9.x

From remote

System access

This covers vulnerabilities where malicious people are able to gain system access and execute arbitrary code with the privileges of a local user.

Secunia Research has discovered two vulnerabilities in Citrix Access Gateway Plug-in for Windows, which can be exploited by malicious people to compromise a user's system.

1) A boundary error in the nsepacom ActiveX control (nsepa.exe) when processing HTTP responses based on the request via the "StartEpa()" method can be exploited to cause a heap-based buffer overflow via an overly long "CSEC" HTTP response header.

2) An integer overflow error in the nsepacom ActiveX control (nsepa.exe) when processing HTTP responses based on the request via the "StartEpa()" method can be exploited to cause a heap-based buffer overflow via a specially crafted "Content-Length" HTTP response header.

Successful exploitation of the vulnerabilities allows execution of arbitrary code.

The vulnerabilities are confirmed in version 9.3.49.5 and reportedly affect the following versions:
* 10.0 prior to 10.0-69.4
* 9.3 prior to 9.3-57.5
* 9.2 (all versions)
* 9.1 (all versions)
* 9.0 (all versions)

Update to version 10.0-69.4 or 9.3-57.5.
https://www.citrix.com/English/ss/downloads/results.asp?productID=15005

Dmitriy Pletnev, Secunia Research.

Secunia Research:
http://secunia.com/secunia_research/2012-26/
http://secunia.com/secunia_research/2012-27/

Citrix:
http://support.citrix.com/article/CTX134303