Windows 2000 Group Policy File Vulnerability Patch

From Microsoft:

This update resolves the "Opening Group Policy Files for Exclusive Read Access Blocks Policy Application" issue affecting Windows 2000 domain controllers and is discussed in Microsoft Security Bulletin MS02-016. Download it to prevent an attacker from blocking the application of Group Policy within a Windows 2000 domain.

Group Policy enables a domain administrator to specify settings for groups of computers and users on a network, such as security settings, desktop settings, and applications that can be installed. Blocking the policy allows an attacker to retain older policy settings rather than being subject to any new ones the administrator had instituted.