Sony DRM Rootkit は Microsoft Anti-Malware Technology Team からも malware と認定されたようです。
Sony DRM Rootkit
We are concerned about any malware and its impact on our customers' machines. Rootkits have a clearly negative impact on not only the security, but also the reliability and performance of their systems.
We have analyzed this software, and have determined that in order to help protect our customers we will add a detection and removal signature for the rootkit component of the XCP software to the Windows AntiSpyware beta,
Good job MS!