Microsoft has officially filed a federal lawsuit against the hacker, known by the pseudonym "Viodentia", who developed a software patch that allowed users to remove the Digital Rights Media (DRM) code from the Windows Media Player application.

The hack, titled FairUse4WM, tackles the media player’s infrastructure that identifies music or videos that have been tagged with a special anti-copying code. Subscription music services, like Napster and Yahoo Music, are among the most well-known users of this technology. Without DRM attached, users are able to make unauthorized copies of the songs.

Microsoft released multiple patches that counter what the FairUse4WM software did, because the fast-acting hacker was quickly able to update the hack to circumvent a new patch.

According to ZDNet, a senior Microsoft attorney alleges that Viodentia must have unlawfully gained access to the company’s confidential source code for Windows Media Player, and that there would be no other way for him to have been able to release an update to the hack that went around the security patch so quickly.

Viodentia denies the claim. "FairUse4WM has been my own creation, and has never involved Microsoft source code. I link with Microsoft’s static libraries provided with the compiler and various platform SDK files," he said in an online post this morning.