A new Microsoft Security Bullitin was (MS13-029) was made available today related to the Remote Desktop Client. The security update is rated Critical for Remote Desktop Connection 6.1 Client and Remote Desktop Connection 7.0. Everything below Windows 7 SP1 and Windows Server 2003 with SP2 is affected!
“…This security update resolves a privately reported vulnerability in Windows Remote Desktop Client. The vulnerability could allow remote code execution if a user views a specially crafted webpage. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.
This security update is rated Critical for Remote Desktop Connection 6.1 Client and Remote Desktop Connection 7.0 Client where affected on Windows XP, Windows Vista, and Windows 7. It is rated Moderate for Remote Desktop Connection 6.1 Client and Remote Desktop Connection 7.0 Client where affected on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2. For more information, see the subsection, Affected and Non-Affected Software, in this section.
The security update addresses the vulnerability by modifying the way that Remote Desktop Client handles objects 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. Most 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…”
Source and more info: http://technet.microsoft.com/en-us/security/bulletin/MS13-029
Related KB: https://support.microsoft.com/kb/2828223?wa=wsignin1.0