Microsoft's Security Intelligence Report, a study of bot infections, reveals that the United States has, by far, the most PCs running naughty malware. However, as you probably guessed, the number is high in part because we have so many more PCs than anyone else. In more absolute terms, Turkey was the big champ, with 36.6 computers infected per 1,000, followed closely by Spain, Korea and Taiwan. America wasn't even in the top five, but Microsoft still labels it bright red, as in "you probably should take some precautions."
The way Microsoft tracks this is by counting how many times its Malicious Software Removal Tool actually cleans malware out of a system. Using that metric, perhaps it's good news that in the first quarter of 2010, the software cleaned 11 million PCs in the U.S., while in the second quarter, it only cleaned 9.6 million, a nearly 13% decline. Which is nice.
