Microsoft has downplayed the impact of a new hack of its digital rights management (DRM) technology, underlining the difficulties in erecting a long-lasting digital barrier against piracy., a hacking forum, contained a post last Friday from "Divine Tao," presumably the hacker responsible, with download links for the updated version of FairUse4WM. The program, which was released last August, strips the DRM technology that limits how Windows Media files can be used and prevents illegal file sharing.

"Microsoft is aware of the DRM issue, and the breach response team is verifying the circumvention," said a company statement.

Windows Media DRM is used, for example, on songs sold through online song retailer Napster. Songs purchased from there can't be copied to more than three computers, but there are no restrictions on how many times an individual song can be burned to a CD.

Hacking activists argue they created FairUse4WM since they deserve broader freedom to move legitimately purchased content from device to device.

Removal of the DRM, however, also allows the files to be copied without restriction or uploaded to file-sharing networks, which the recording industry believes has caused a massive sales decline.

Microsoft has updated its DRM technology at least twice before to halt the effectiveness of FairUse4WM and said its DRM system is designed to support dynamic updates. The updates do not require a new release of Windows Media Player or the Windows Media Format Software Development Kit, used by developers to employ the DRM system, Microsoft said.

Microsoft did not give a timetable as to when it may update Windows Media DRM to block the latest version of FairUse4WM.

Nonetheless, the company acknowledged the DRM system's inherent vulnerability to hackers. "Microsoft has long stated that no DRM system is impervious to circumvention, a position Microsoft's content partners are aware of as well," the company said.

Microsoft filed a lawsuit in a district court in Seattle last September against 10 unnamed defendants for copyright infringement related to the release of FairUse4WM. The suit, however, was later dropped after the defendants could not be located.

Record labels are increasingly considering removing DRM from their songs after years of lawsuits and legal wrangling have done little to reduce illegal file-sharing.

In April, EMI said it would sell songs on Apple's iTunes Music Store without DRM. The DRM-free songs cost about 20 percent more but are also encoded at 256K bps, a higher quality than other songs with DRM.