“In October 2013, Microsoft adopted a silent, offensive method to tackle infection due to a Tor-based botnet malware called ‘Sefnit‘. In an effort to takedown of the Sefnit botnet to protect windows users, Microsoft remotely removes the older versions of installed Tor Browser software and infection from 2 Million systems, even without the knowledge of the system’s owner. It was not practically possible for Microsoft or the Government to instruct each individual on ‘How to remove this Malware‘, so finally Microsoft took the decision of remotely washing out the infections themselves. Microsoft’s action clarifies the capability to remotely remove any software from your computer.”
http://thehackernews.com/2014/01/microsoft-remotely-deleted-tor-browser.html