Tuesday, March 13, 2012

Microsoft Security Bulletin MS12-020 - Critical - Vulnerabilities in Remote Desktop Could Allow Remote Code Execution (2671387)

Microsoft has released a critical security bulletin today on Remote Desktop

Microsoft Security Bulletin MS12-020 - Critical
Vulnerabilities in Remote Desktop Could Allow Remote Code Execution (2671387)
Published: Tuesday, March 13, 2012

For the complete bulletin please see: http://technet.microsoft.com/en-us/security/bulletin/ms12-020

"...Executive Summary
This security update resolves two privately reported vulnerabilities in the Remote Desktop Protocol. The more severe of these vulnerabilities could allow remote code execution if an attacker sends a sequence of specially crafted RDP packets to an affected system. By default, the Remote Desktop Protocol (RDP) is not enabled on any Windows operating system. Systems that do not have RDP enabled are not at risk.
This security update is rated Critical for all supported releases of Microsoft Windows. For more information, see the subsection, Affected and Non-Affected Software, in this section.
The security update addresses the vulnerabilities by modifying the way that the Remote Desktop Protocol processes packets in memory and the way that the RDP service processes packets. For more information about the vulnerabilities, see the Frequently Asked Questions (FAQ) subsection for the specific vulnerability entry under the next section, Vulnerability Information.
Recommendation. The majority of customers have automatic updating enabled and will not need to take any action because this security update will be downloaded and installed automatically. Customers who have not enabled automatic updating need to check for updates and install this update manually. For information about specific configuration options in automatic updating, see Microsoft Knowledge Base Article 294871.
For administrators and enterprise installations, or end users who want to install this security update manually, Microsoft recommends that customers apply the update immediately using update management software, or by checking for updates using the Microsoft Update service.
See also the section, Detection and Deployment Tools and Guidance, later in this bulletin.
Known Issues. Microsoft Knowledge Base Article 2671387 documents the currently known issues that customers may experience when installing this security update. The article also documents recommended solutions for these issues..."


  1. A mate and I are putting together a little web-based tool for folk to check their exposure to this vulnerability from the Internet. It’s at http://rdpcheck.com

  2. In my system log I see Error "The Terminal Server security layer detected an error in the protocol stream and has disconnected the client." Does that indicate an attempt to exploit this vulnerability? My system is already patched, and I'm assuming that error indicates it has caught and stopped the attempt.