Storm Botnet
The Storm botnet is a remotely controlled network of computers ( botnet ) that on the Storm Worm - a Trojan horse that spreads via spam - are interrelated.
The Storm botnet was first discovered in January 2007, when the Storm Worm accounted for about 8% of malware on Windows operating systems.
In September 2007, the botnet was estimated at a size of 1 to 10 million PCs because of the spam sent. These estimates were not very accurate, so that different analysts came to very different results.
On 11 September 2007 Microsoft spread the MSRT tool to automatically remove malicious software, which removed within the first week of Storm 274 372 PCs via Windows Update.
The exact size of the botnet was determined in April 2008 by scientists at the University of Mannheim. A crawler pulled himself through the Overnet network and is based on the time of day 5000-40000 Storm bots that were online at the same time.
The Storm botnet in 2008 was the subject of a scientific study on the effectiveness of spam networks in years.