In its semi-annual Security Intelligence Report, Microsoft found that the United States leads the world in both total infections and botnet infiltrations.
The internet security survey reported over 20 million malware infections on U.S. computers during the past two quarters combined. Brazil came in second with 4 million infections over the same time period. China, France and Spain rounded out the top five.
The study also included a study of botnet infections. Once again, the U.S. topped the list for total infections. Over 4 million U.S. computers had botnets cleaned over the two quarters. Brazil was second again, with over 1 million botnet infections. Spain, Korea, and Mexico followed.
The Win32/Rimecud was the most active botnet, followed by Win32/Alureon, according to the report. Win32/Nuwar had the biggest activity jump, going from 8,098 infections in the first quarter to 133,951 in the second, an increase of 1,554 percent.
Microsoft conducted the study by scanning the Microsoft Security Essentials results of 600 million computers worldwide. The study was conducted from January through June of this year.
Microsoft has made efforts to counter botnets. It recently released an update to find and delete the Zeus botnet, and Microsoft security chief Scott Charney pitched a proposal to block botnet infected computers from the internet.