A simple JavaScript command pasted into the address bar of the Internet Explorer or Firefox Web browsers reportedly lets users avoid the new software-authentication system -- called Windows Genuine Advantage -- that aims to reduce access to application updates from pirated versions of Windows.

Microsoft is aware of the hack and is working on a patch, but hackers already are talking of posting an update to bypass the forthcoming patch.

ActiveX Controls

The Genuine Advantage program relies on an ActiveX control to confirm that a Windows user owns a valid copy of the software. If a pirated version is discovered, Microsoft will not allow software to be updated through the automatic Windows Update service nor through other update methods accessed on Microsoft's Web sites.

Some 80 million Windows users currently take advantage of regular software patches through Microsoft's update services. Although Microsoft's new program bars application updates on pirated versions of Windows, the software giant still does permit security updates on these systems.

Prior Hacks

In May, an Indian researcher published how to defeat the Genuine Advantage process while the antipiracy program was still in the testing stage. At that time, Microsoft admitted counterfeiters would attempt to defeat the measure, but also said that any weaknesses found in the validation procedure would not facilitate widespread piracy.

Even if consumers can avoid the antipiracy program using the JavaScript workarounds, the purpose of the program is to target the people selling counterfeit copies of Windows, said Joe Wilcox, a Jupiter Research analyst. The Windows Genuine Advantage program should have an impact on emerging markets where piracy is more prevalent, the analyst said.

The new program, announced earlier this week, gives users with pirated copies of Windows the ability to upgrade to an authentic copy for free -- if they provide the pirated CD-ROM -- or to purchase the software at discounted rates.