In an advisory on January 14, 2010, Microsoft said that attackers targeting Google and other U.S. companies used software that exploits a security hole, which had already been patched, in Internet Explorer. The vulnerability affected Internet Explorer 6, IE7, and IE8 on Windows 7, Vista, Windows XP, Server 2003, and Server 2008 R2, as well as IE 6 Service Pack 1 on Windows 2000 Service Pack 4.