Windows Wave reports a flaw in Microsoft's Windows 8 activation process enables pirates to get the new operating system for free. The trick works by installing the operating system using any Windows 8 key (even one that's already in use) and applying a KMS (Key Management System) activation, which gives you 180 days before another legitimacy test is performed. The next step is to apply for Windows 8 Media Center, which is available for free to every Windows 8 Pro user until January 31, 2013. No legitimacy check is performed when upgrading to Windows 8 Media Center, and the upgrade key permanently replaces your Windows 8 key, enabling you to activate a non-legit Windows 8 copy.
Essentially, those who wish to get a free legitimate installation only need a key for the Windows Media Center upgrade, which is available directly from Microsoft. They simply use any Windows 8 key to reach the desktop during installation of a pirated copy of Windows 8, apply a KMS activation for their current version (to prevent piracy we will not be covering this step in detail), and then go on to use the Windows Media Center upgrade key they obtained from Microsoft themselves. Due to the fact that the WMC upgrade process does no checks for the validity of the activation, any activated copy of windows (even ones which were activated via KMS) are upgraded to a valid version of Windows 8 via the WMC upgrade. Uh oh!
A Key Management System activation allows your unlicensed copy of Windows to be fully usable for 180 days. It’s typically used to help Volume Licensing customers automate and manage the activation process, but pirates have found a way to take advantage of it. On top of that, Microsoft is simply handing out unlimited upgrade keys for Windows Media Center, providing a gateway to free activations.