Microsoft announced five vulnerabilities deemed "critical" by the software giant, the top rating that Microsoft assigns to security flaws. The ranking is used to designate security flaws that could allow online vandals to take control of a user's computer or create an Internet worm that could spread from system to system.

"All of the five critical (vulnerabilities) are, of course, critical, so that means they are wormable," said Jeff Jones, senior director of Microsoft's security business unit.

Three of the critical flaws affect all of the Windows operating systems currently supported by Microsoft, including various editions of Windows NT, Windows 2000, Windows XP and Windows Server 2003. Another critical flaw affects only Windows 2000, and the fifth such flaw affects Microsoft's Exchange Server 5.5 and Exchange 2000 Server products. More information on the flaws--numbered MS03-041 to MS03-047--can be found on Microsoft's security Web page. (http://zdnet.com.com/redir?destUrl=http%3A%2F%2Fwww.microsoft.com%2Ftechnet%2Ftreeview%2Fdefault.asp%3Furl%3D%2Ftechnet%2Fsecurity%2FDefault.asp&siteId=2&oId=2100-1105-5091835&ontId=11&lop=nl_ex)

Please make sure you have installed the patches for these flaws from http://v4.windowsupdate.microsoft.com/en/default.asp