Microsoft recently announced its plans to buy the anti-virus software maker Sybari Software to beef up security features in its Windows operating system. This is the third major security-related acquisition by Microsoft in the last few years and has sent jitters to anti-virus software vendors such as McAfee and Symantec. This move by Microsoft also indicates bundling of security features in all its future products including Longhorn to be released in 2006. Microsoft Windows has always been the victim of virus and security attacks. Notable ones being Code Red worm released on July 19, 2001 which exploited vulnerability in Microsoft Internet Information Server, affecting more than 250,000 computer systems in less than nine hours. Released on January 25, 2003, Slammer exploiting vulnerability in Microsoft SQL Server 2000, spread with astonishing speed, infecting 90% of all vulnerable computers on the Internet within 10 minutes. Similarly W32/Blaster worm exploited Windows vulnerability and attacked more than 7,000 computers in minutes of its release on black Monday, August 11, 2003.