According to a new 240-page security report from Microsoft dubbed the Security Intelligence Report, America is among the most infected countries in the world when it comes to botnets.  The report uses information collected in the first half of 2010 via the Microsoft Malicious Software Removal Tool.

Over 2.2 million PCs in the U.S. are infected with a virus that makes them part of one of the internet's massive botnets.  The term "botnet" refers to a group of connected computers that can be used for ill purposes such as spamming, distributed denial of service (DDoS) attacks, and mass credit card fraud.

Brazil came in second place for most infected computers, with 550,000 botnet-infected PCs.  Per computer population, though South Korea had the highest rate (though its total number of infected machines is lower than that of the U.S. or Brazil).  In South Korea 14.6 out of 1,000 PCs are in a botnet, versus 5.2 computers out of 1,000 in the U.S.

Cliff Evans, head of security and identity at Microsoft UK, comments to BBC News, "Most people have this idea of a virus and how it used to announce itself.  Few people know about botnets."

Fewer people perhaps know about Microsoft's Malicious Software Removal Tool (MRT).  MRT has been is a free tool Microsoft includes with Windows XP, Windows Vista, and Windows 7.  First released in 2005, the tool is easy to run -- just go to "Start", type "run" in the search bar, and then type "mrt" (case insensitive) in the resulting popup.  The tool will then activate and be ready to scan your computer and remove many common types of malware.

Perhaps if everyone learns how to use the MRT, America can escape earning the dubious distinction of being the world's biggest botnet participant in 2011.  Given the general public's ignorance of security, that seems unlikely, though.

Despite the difficulty in getting the public to practice proper security, Microsoft is taking steps to try to win the war against botnet masters on its own.  The company recently seized control over 276 internet domains that were being used by botnet owners.  And it has beefed up the securityof its most recent operating system, Windows 7, making it harder to infect new PCs.