2.2 million US PCs are pwned by botnets

More than 2.2 million US PCs have been recruited into botnets, according to a report from Microsoft.

Redmond found that the Land of the Free is mostly trapped in botnets and that Spain has the most infected machines in Europe.

Microsoft said in its Security Intelligence Report that between April 2010 and June 2010, its software cleaned more than 6.5 million computers of botnet infections. This is twice the number of infections the year before.

The Security Intelligence Report contains analysis of data from over 600 million PCs worldwide.

Microsoft’s research shows that there are geographical variances in the botnet problem. In the second quarter of 2010, the United States had the most botnet infections, 2.2 million, followed by Brazil with 550,000.

In Europe, Spain had 382,000 infections followed by France, the UK and Germany.

South Korea was found to have the highest incidence of botnet infection of 14.6 botnet infections per 1,000 computers scanned, followed by Spain with 12.4 and Mexico, 11.4.

The largest botnet in the world was Rimecud with infections increasing by  860 percent in the last three months of 2009. In second place, with 70 percent fewer infections, is Alureon.