There is a pirated Vista killer roaming free on Windows Update. Microsoft is not limiting itself to Service Pack 1 for Windows Vista and to the Windows Genuine Advantage anti-piracy mechanism when it comes down to hunting down pirated copies of the operating system.

In fact, an update from the Redmond company is designed specifically to make Vista capable of detecting what the software giant referred to as activation exploits. The refresh is served to Vista clients worldwide via Windows Update, with no user intervention, provided that the WU settings are set to automatic updating.

Microsoft failed to reveal the specific Vista activation cracks that were targeted by the KB940510 update. Vista SP1 for example was designed to render useless the OEM BIOS and Grace Timer cracks.

The company only informed that “this update for Windows Vista detects activation exploits that may be present on a system. An activation exploit bypasses licensing and activation. This behavior allows for counterfeit copies of Windows Vista to run without ever having to be activated. Activation exploits make alterations to key Windows system files. These activation exploits affect both system stability and security.”

According to Microsoft, the pirated Vista killer bits will integrate exclusively with the following SKUs of the operating system: Business, Home Basic, Home Premium, Starter and Ultimate, however, not with the Enterprise edition.

The update will be able to detect any interferences with the normal Windows operation, and alert the user of any activation exploits. In the context in which a copy of the client is genuine, the update will take absolutely no action. The same is not valid for pirated Vista versions, which do bypass product activation.

“If activation exploits are detected, you will be provided a link to a Web site that describes how you can remove the activation exploits. When the activation exploits are removed, you may be asked to use a valid product key to activate your copy of Windows. If you do not want to remove the activation exploits, Windows may disable the activation exploits, and then ask you to use a valid product key to activate Windows,” Microsoft informed.