After finally settling its rootkit fiasco in 2005, Sony BMG is suing the maker of the digital rights management (DRM) software which it used to protect its content. 

The suit accuses The Amergence Group, formerly known as SunnComm, of negligence and unfair business practices. Sony BMG is asking for $12m in damages. 

SunnComm's MediaMax was included on some Sony BMG CDs in an attempt to limit the number of times the disc could be copied.

But many users discovered that the MediaMax software created a directory on computers which could potentially allow hackers to hijack the PC.

The MediaMax vulnerability came just weeks after Sony BMG came under fire for a different piece of DRM software which it put on its CDs. The XCP software from UK firm First4Internet was found to install rootkits on systems. 

A rootkit is program that runs at a very low level of the system, allowing code to run undetected by antivirus software.

The XCP technology became a favourite tool for attackers to install and execute malware, and users attempting to remove the rootkit experienced CD-Rom drive crashes. 

Amergence Group has said that it intends to defend itself against what it believes are unwarranted allegations by the entertainment giant.

The company said in a statement: "The suit alleges, among other things, that SunnComm's CD copy protection component, called MediaMax, was defective and that the small Phoenix-based company has a contractual obligation to indemnify the entertainment giant against consumer actions which Amergence believes resulted primarily from 1) Sony's under-tested release of a competitor's technology, and 2) BMG's 'final authority' input in determining the functional specifications of the MediaMax copy protection."