This update resolves the "Winsock Mutex" security vulnerability in Windows NT® 4.0 Terminal Server Edition, and is discussed in Microsoft Security Bulletin MS01-003. Download now to help prevent a malicious user from running a special program to disable your network functionality.

This vulnerability exists because the mutex (a tool to prevent more than one process from accessing certain resources at the same time) that is used to control access to networking resources has inappropriately loose permissions. As a result, a malicious user with physical access to a Windows NT 4.0 Terminal Server Edition computer could write a program to gain control of the mutex and deny access to all other users. By denying access to the mutex, the malicious user's program could prevent any other programs from using the networking functions of the affected computer. This update corrects the inappropriate permissions of the affected mutex.

1. Click Start, point to Settings, and then click Control Panel.
2. Double-click Add/Remove Programs.
3. Select Windows 4.0 Hotfix [See Q279336 for more information] and click Add/Remove Programs to uninstall.