It is a group of vulnerabilities in Internet Explorer versions 5.01 and 6 SP1 on Windows 2000, 6 on Windows 2003/XP computers, 7 on Windows 2008/Vista/2003/XP and 8 on Windows 7/2008/Vista/2003/XP, which allows hackers to gain remote control of the affected computer with the same privileges as the logged on user.