MBSA is the free, best practices vulnerability assessment tool for the Microsoft platform. It is a tool designed for the IT Professional that helps with the assessment phase of an overall security management strategy. MBSA Version 1.2.1 includes a graphical and command line interface that can perform local or remote scans of Windows systems.
MBSA runs on:
• Windows 2000, Windows XP, and Windows Server 2003 systems
MBSA will scan for common system misconfigurations in the following products:
• Windows NT 4.0, Windows 2000, Windows XP, Windows Server 2003
• Internet Information Server (IIS), SQL Server, Internet Explorer, Office
MBSA will also scan for missing security updates for the following products:
• Windows NT 4.0, Windows 2000, Windows XP, Windows Server 2003
• IIS, SQL Server, Internet Explorer, Office, Exchange Server, Windows Media Player, Microsoft Data Access Components (MDAC), MSXML, Microsoft Virtual Machine, Commerce Server, Content Management Server, BizTalk Server, Host Integration Server.
More information
here.