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AUSCERT External Security Bulletin Redistribution
ESB-2011.0343
Vulnerability in the ActiveSync feature of Citrix Presentation Server and
XenApp could result in arbitrary code execution
28 March 2011
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AusCERT Security Bulletin Summary
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Product: XenApp Fundamentals 2.0
XenApp 5.0 for Windows Server 2008
Presentation Server 4.5 for Windows Server 2003
Publisher: Citrix
Operating System: Windows Server 2008
Windows Server 2003
Impact/Access: Execute Arbitrary Code/Commands -- Remote/Unauthenticated
Resolution: Patch/Upgrade
Original Bulletin:
http://support.citrix.com/article/CTX128366
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Vulnerability in the ActiveSync feature of Citrix Presentation Server and
XenApp could result in arbitrary code execution
Document ID: CTX128366 / Created On: Mar 23, 2011 / Updated
On: Mar 23, 2011
Average Rating: not yet rated
View products this document applies to link to products this document
applies to
Severity: High
Description of Problem
A vulnerability has been identified in the ActiveSync feature of
Citrix Presentation Server 4.5 and Citrix XenApp 5 that, when
triggered, could result in a arbitrary code execution.
The ActiveSync feature provides users with the ability to remotely
synchronize PDA devices with published applications such as Microsoft
Outlook. When a specially crafted packet is sent to a vulnerable
server, the ActiveSync service terminates unexpectedly.
This vulnerability affects Citrix Presentation Server version 4.5 and
Citrix XenApp 5 for Windows Server 2003. The affected service is
enabled by default on these platforms.
Mitigating Factors
Access to port 28875 on the Presentation Server or XenApp server would
be needed to trigger the vulnerability.
What Customers Should Do
A hotfix has been released to address this issue. Citrix recommends
that affected customers install this hotfix, which can be downloaded
from the following locations:
Citrix Presentation Server 4.5 with Feature Pack/XenApp 5 for Windows
Server 2003 x86:
EN - http://support.citrix.com/article/CTX125534
FR - http://support.citrix.com/article/CTX125535
DE - http://support.citrix.com/article/CTX125536
JA - http://support.citrix.com/article/CTX125704
ES - http://support.citrix.com/article/CTX125537
Citrix Presentation Server 4.5 with Feature Pack/XenApp 5 for Windows
Server 2003 x64:
EN - http://support.citrix.com/article/CTX125705
FR - http://support.citrix.com/article/CTX125706
DE - http://support.citrix.com/article/CTX125707
JA - http://support.citrix.com/article/CTX125709
ES - http://support.citrix.com/article/CTX125708
Citrix Access Essentials 2.0:
EN - http://support.citrix.com/article/CTX125534
FR - http://support.citrix.com/article/CTX125535
DE - http://support.citrix.com/article/CTX125536
ES - http://support.citrix.com/article/CTX125537
Citrix also recommends that customers who do not use this feature
disable the Citrix ActiveSync Service even after the hotfix has been
applied.
Acknowledgements
Citrix thanks AbdulAziz Hariri, working with Secunia, for working with
us to protect Citrix customers.
What Citrix Is Doing
Citrix is notifying customers and channel partners about this
potential security issue. This article is also available from the
Citrix Knowledge Center at http://support.citrix.com/.
Obtaining Support on This Issue
If you require technical assistance with this issue, please contact
Citrix Technical Support. Contact details for Citrix Technical Support
are available at
http://www.citrix.com/site/ss/supportContacts.asp.
Reporting Security Vulnerabilities to Citrix
Citrix welcomes input regarding the security of its products and
considers any and all potential vulnerabilities seriously. If you
would like to report a security issue to Citrix, please compose an
e-mail to secure@citrix.com stating the exact version of the product
in which the vulnerability was found and the steps needed to reproduce
the vulnerability
This document applies to:
* Feature Pack 1 for Presentation Server 4.5
* Presentation Server 4.5 for Windows Server 2003 x64 Edition
* XenApp 5.0 for Windows Server 2008 x64
* XenApp 5.0 for Windows Server 2008 x86
* XenApp Fundamentals 2.0
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