When Sony BMG put their hidden "root kit" copy protection system on music CDs, do you think they knew someone would discover it and a string of lawsuits would follow?

Well, they do now.

The media giant is poised to be on the receiving end of three separate lawsuits from California and New York over the use of the said "root kit" - a program which secretly installs itself onto users computers without their knowledge. Once stealthfully installed, the "kit" hides itself, making its removal impossible without a special tool available only from Sony.

Windows expert Mark Russinovich found the code last month.

The actual program is known as XCP.Sony.Rootkit Extended Copy Protection(XCP) and is Digital Rights Management (DRM) software manufactured by a UK company called First4Internet.

Digital rights group, the Electronic Frontier Foundation (EFF) is also trying to gain information from users to see if a possible class action claim can be brought against Sony.

In further developments, Computer Associates reclassified Sony's software as spyware and will begin searching for and removing XCP with its anti-spyware software.