Microsoft accidentally gives pirates the keys to Windows 8

Microsoft’s giveaway of a free Windows Media Center upgrade may have a curious side effect: allowing pirates to pick up a free copy of Windows 8 Pro direct from Microsoft itself.

The Media Center upgrade, which Microsoft is offering through January 31, 2013, includes Microsoft’s tools for watching and recording live TV. However, applying the upgrade has an unintended side effect: It permanently activates the copy of Windows 8 that you’ve applied it to.

That provides a neat workaround for pirates who exploit a weakness in Microsoft’s Key Management Service (KMS) to get temporary access to copies of Windows 8. Normally, KMS provides a way for corporate IT people to activate copies of Windows on a local network without having to make each PC contact Microsoft directly for authentication during the install process, but it has also given rise to pirate KMS servers, which hand out activation keys over the Internet. With KMS, you need to re-activate Windows every 180 days, making this sort of piracy rather limited in effectiveness.

However, the Media Center upgrade reportedly works even on KMS-authorized installations of Windows, turning KMS-hacked PCs into permanently-authenticated copies of Windows.

We haven’t been able to verify the effectiveness of this hack, we don’t know for sure that it works, and we, of course, we don’t recommend it — piracy is illegal. Details first popped up on Reddit, where commenters were quick to spot the 2006 article in which Bill Gates said, regarding Chinese Windows pirates, “As long as they’re going to steal it, we want them to steal ours.”

Stephen Hall at Windows Wave pointed out the exploit to us, and reports that Windows Wave has been able to confirm that it works.