I've been getting a lot of questions in the last week about Microsoft's position on the Sony DRM and rootkit discussions, so I thought I'd share a little info on what we're doing here. 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 use a set of objective criteria for both Windows Defender and the Malicious Software Removal Tool to determine what software will be classified for detection and removal by our anti-malware technology. 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, which is currently used by millions of users. This signature will be available to current beta users through the normal Windows AntiSpyware beta signature update process, which has been providing weekly signature updates for almost a year now. Detection and removal of this rootkit component will also appear in Windows Defender when its first public beta is available. We also plan to include this signature in the December monthly update to the Malicious Software Removal Tool. It will also be included in the signature set for the online scanner on Windows Live Safety Center.