Citrix Presentation Server 4.0 IMA Service Invalid Name Length DoS
Vulnerability

iDefense Security Advisory 11.08.06
http://labs.idefense.com/intelligence/vulnerabilities/
Nov 08, 2006

I. BACKGROUND

Citrix Presentation Server is a product designed to allow remote access to
applications over a network.  More information can be found at the Citrix's
web site:
http://www.citrix.com/English/ps2/products/product.asp?contentID=186.

II. DESCRIPTION

Remote exploitation of an input validation error in Citrix Systems Inc.'s
Metaframe Presentation Server 4.0 IMA service may allow an attacker to
cause a denial of service (DoS) condition.

The IMA (Independent Management Architecture) server component Citrix's
Presentation Server (previously known as Metaframe) contains an input
validation error in the handling of certain packet types. By constructing a
specific packet, it is possible to cause the service to reference an
unmapped memory address. This causes an unhandled exception, which in turn
causes the service to exit, resulting in a DoS condition.

III. ANALYSIS

Successful exploitation of this vulnerability would allow a remote attacker
to cause the IMA server component of the Citrix Presentation Server to
crash, preventing access to the resources being shared on the server.

IV. DETECTION

This vulnerability has been confirmed to affect Citrix Presentation Server
4.0.  Previous versions may also be affected.

V. WORKAROUND

iDefense is unaware of any effective workarounds for this vulnerability.

VI. VENDOR RESPONSE

The vendor has released the following advisory to address this issue:

http://support.citrix.com/article/CTX111186

VII. CVE INFORMATION

A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not
been assigned yet.

VIII. DISCLOSURE TIMELINE

07/03/2006  Initial vendor notification
07/05/2006  Initial vendor response
11/09/2006  Coordinated public disclosure

IX. CREDIT

This vulnerability was reported to iDefense by Eric Detoisien.

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X. LEGAL NOTICES

Copyright © 2006 iDefense, Inc.

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Disclaimer: The information in the advisory is believed to be accurate at
the time of publishing based on currently available information. Use of
the information constitutes acceptance for use in an AS IS condition.
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 arising from use of, or reliance on, this
information.