Microsoft has admitted that one of its own download tools could allow users of unlicensed or pirated Microsoft software to download additional software from the company.
A security researcher has discovered that Microsoft's Windows Genuine Advantage validation check can be circumnavigated by using a secondary validation tool called GenuineCheck.exe.
By running GenuineCheck.exe, unauthorised users could download additional free software from the company’s Download Center, such as Windows Media Player, Windows AntiSpyware and security updates.
GenuineCheck.exe is supposed to offer users an alternative way to prove that their copy of Windows is genuine. Microsoft allows the alternative validation method because the Windows Genuine Advantage checking mechanism uses ActiveX, which is not supported in all web browsers.
But GenuineCheck generates a code that can subsequently be used to validate a pirated copy of Windows, according to a security researcher posting on the Full Disclosure mailing list.
The code generated, however, is only temporary, so unauthorised users have to use it soon after generation to download software.