The country is responsible for exporting 43 percent of all spam and leads a list of the top 12 spam-producing nations.
With the data in its “Dirty Dozen” list, Sophos said that measures to squelch spam have been disappointing.
"Six months [after the Can-Spam Act] and millions of spam messages later, it is quite evident that the legislation has made very little headway in damming the flood of spam,” Sophos analyst Chris Kraft told XBiz. “If nine months isn't long enough to make a significant difference, how long is?"
Lynnfield, Mass.-based Sophos released the first analysis of spam origins in February.
According to Sophos, the top 12 spam-producing countries are as follows: United States, 43 percent; South Korea, 15 percent; China (including Hong Kong) 12 percent; Brazil, 6 percent; Canada, 3 percent; Japan, 3 percent; Germany, 1 percent; France, 1 percent; Spain, 1 percent; United Kingdom, 1 percent; Mexico, 1 percent; and Taiwan 1 percent. Other nations accounted for 12 percent of all spam.
Sophos said that the most broadband-connected nation in the world, South Korea, has consolidated its position as a leading producer of spam - almost tripling the percentage of spam originating from its shores since February.
Kraft told XBiz that most PCs sending out spam are most likely to have had their broadband connections exploited by remote hackers. Zombie computers — PCs that have been compromised by hackers or virus writers — are sending out approximately 40 percent of the world's spam, and many users who fall victim are unaware.
"It's of no surprise that spammers are motivated by one thing - quick, easy money," Kraft said. "There are plenty of spammers who have taken their money making schemes to the extreme by hacking into innocent third-party computers in an effort to do their dirty work.”