In March, Microsoft announced that its Digital Crimes Unit had scored a major victory in the war against hackers with the takedown of the Rustock botnet. The number of unique machines connecting to the control server for Rustock that the company has sinkholed dropped by more than 56 percent. India still has the highest number of infected PCs and the United States moved up from number four on that list in March, to number two in June. There are still several hundred thousand unique IP addresses that are compromised by the malware and trying to phone home for instructions.
Source: https://threatpost.com/microsoft-says-rustock-botnet-cut-half-070511/75395/