Description of Problem
The Session Reliability service is used by some Citrix products to improve user experience when connecting over unreliable networks. By sending a specifically crafted request to this service, an attacker could establish a TCP connection to any port on the local machine. This could be used by the attacker to bypass network security policies and remotely access local ports on the target machine.
This vulnerability is present in the following versions of Citrix products:
• Citrix MetaFrame Presentation Server 3.0
• Citrix Presentation Server 4.0
• Citrix Access Essentials 1.0
• Citrix Access Essentials 1.5
No other versions of Citrix Presentation Server, Citrix Access Essentials or Citrix Desktop Server are affected by this issue.
Customers running an affected product with the Session Reliability feature disabled are not affected by this issue.
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:
MetaFrame Presentation Server 3.0 for Windows 2000 Server:
MetaFrame Presentation Server 3.0 for Windows Server 2003:
Citrix Presentation Server 4.0 for Windows 2000 Server:
Citrix Presentation Server 4.0 for Windows Server 2003:
Citrix Presentation Server 4.0 for Windows Server 2003 x64 Editions:
Citrix Access Essentials 1.0:
Citrix Access Essentials 1.5:
Citrix thanks Andrew Christensen of FortConsult working with us to protect Citrix customers.
What Citrix Is Doing
Citrix is proactively notifying customers and channel partners about this potential security issue. This article is also available from the Citrix Knowledge Base at http://support.citrix.com/.
Obtaining Support on this Issue
If you require technical assistance with this issue, please contact Citrix Technical Support. Information for contacting Citrix Technical Support is available at http://support.citrix.com/.
Reporting Security Vulnerabilities to Citrix
Citrix welcomes input regarding the security of its products and considers any and all potential vulnerabilities very seriously. If you would like to report a security issue to Citrix, please compose an e-mail to email@example.com containing the exact version of the product in which the vulnerability was found and the steps needed to reproduce the vulnerability.