Just seen this: http://www.microsoft.com/technet/security/bulletin/MS10-106.mspx
This security update resolves a privately reported vulnerability in Microsoft Exchange Server. The vulnerability could allow denial of service if an authenticated attacker sent a specially crafted network message to a computer running the Exchange service. Firewall best practices and standard default firewall configurations can help protect networks from attacks that originate outside the enterprise perimeter. Best practices recommend that systems that are connected to the Internet have a minimal number of ports exposed.
This security update is rated Moderate for Microsoft Exchange Server 2007 Service Pack 2 for x64-based Systems.
- Microsoft Exchange Server 2000 Service Pack 3
- Microsoft Exchange Server 2003 Service Pack 2
- Microsoft Exchange Server 2007 Service Pack 3
- Microsoft Exchange Server 2010
- Microsoft Exchange Server 2010 Service Pack 1