This security update resolves a privately reported vulnerability in the Remote Desktop Protocol. The vulnerability could allow denial of service if an affected system received a sequence of specially crafted RDP packets. Microsoft has also received reports of limited, targeted attacks attempting to exploit this vulnerability. By default, the Remote Desktop Protocol (RDP) is not enabled on any Windows operating system.

This security update is rated Important for all supported editions of Windows Server 2003 and Moderate for all supported editions of Windows XP. For more information, see the subsection, Affected and Non-Affected Software, in this section.

The security update addresses the vulnerability by addressing the way that the Remote Desktop Protocol processes packets in memory. For more information about the vulnerability, 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 at the earliest opportunity 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. None

Reference: http://www.microsoft.com/technet/security/Bulletin/MS11-065.mspx