Citrix Access Gateway Plug-in for Windows ActiveX Control StartEPA() Method HTTP Response Header Parsing Overflows (CTX134303)

This script is Copyright (C) 2012-2013 Tenable Network Security, Inc.


Synopsis :

The remote Windows host has an ActiveX control that is affected by
multiple buffer overflow vulnerabilities.

Description :

The Citrix Access Gateway ActiveX control for Citrix Access Gateway
Enterprise Edition is installed on the remote Windows host. It is the
ActiveX component of the Citrix Access Gateway Plug-in for Windows and
provides an SSL-based VPN via a web browser.

The installed version of this control (nsepa.exe) is affected by the
following vulnerabilities involving the 'StartEPA()' method that could
lead to arbitrary code execution :

- A boundary error exists that can be exploited to cause
a heap-based buffer overflow when processing overly
long 'CSEC' HTTP response headers. (CVE-2011-2592)

- An integer overflow exists that can be exploited to
cause a heap-based buffer overflow when processing
specially crafted 'Content-Length' HTTP response
headers. (CVE-2011-2593)

See also :

http://www.securityfocus.com/archive/1/523728/30/0/threaded
http://www.securityfocus.com/archive/1/523729/30/0/threaded
http://support.citrix.com/article/CTX134303

Solution :

Update to version 9.3-57.5 / 10.0-69.4 or set the kill bit for the
control.

Risk factor :

High / CVSS Base Score : 9.3
(CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C)
CVSS Temporal Score : 6.9
(CVSS2#E:U/RL:OF/RC:ND)
Public Exploit Available : false

Family: Windows

Nessus Plugin ID: 62777 ()

Bugtraq ID: 54754

CVE ID: CVE-2011-2592
CVE-2011-2593

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