The Terminal Server patch issued in Microsoft advisory MS01-052 has been found to be prone to an unspecified denial of service vulnerability. The affected patch was originally issued to deal with the issue outlined in the Microsoft Windows 2000/NT Terminal Server Service RDP DoS Vulnerability (BID 3445). This issue could be leveraged to cause the affected server to stop responding, denying service to legitimate users.
Block external access at the network boundary, unless external parties require service.
If the system is not required to be globally accessible, it is advised that access to it be restricted to only trusted hosts and networks.
Microsoft has issued a patch dealing with this issue. Please see the referenced vendor web advisory for more information and details on obtaining fixes.