News 

The company has previously released two patches disable the FairUse4WM hack, which stripped copy-protection code from media files. The hack prompted at least one company, BSkyB, to suspend access to Web-based content until a fix was provided.

But the apparent discovery that

ADVERTISEMENT

the hacker had gained access to source code detailing how the DRM is deployed has prompted Microsoft to seek legal recourse.

'Our own intellectual property was stolen from us and used to create this tool,' said Bonnie MacNaughton, a Microsoft senior attorney. 'They obviously had a leg up on any of the other hackers that might be creating circumvention tools from scratch.'

The company will continue to patch PlaysForSure, saying that it is not unusual for it to have to continually review the security of new software. It added that the technology had been specifically designed to make it as easy as possible to apply updates where needed.

The lawsuit does not name the alleged hacker, who is known only by his online name of Viodentia. Identifying him using Internet IP addresses will be part of the legal process.

Microsoft's lawyers have also sent legal letters to a number of websites, asking them to remove links to the software.