U.S. cooks up most spam

According to security software firm Sophos, roughly 43 percent of spam sent around the globe originates from the United States, which enacted the federal Can-Spam Act in January to criminalize e-mail fraud.

That percentage dwarfs the junk e-mail coming from South Korea and China, the second- and third-largest sources, respectively. South Korea accounts for 15 percent of the world's spam and China, 12 percent, according to a report from Sophos released Tuesday. Brazil is the fourth-largest exporter of spam at 6 percent.

"Almost nine months on from the Can-Spam legislation and the United States' attempt to clean up its act appears to have had little impact," Graham Cluley, Sophos' senior technology consultant, said in a statement.

Since it became law in December, Can-Spam has failed to push back the rising flood of spam. What's more, a majority of e-mail marketers are not complying fully with the new law, research has shown.

Spam accounts for more than 65 percent of all e-mail processed by mail servers, according to Symantec, a security company that recently bought Brightmail, a spam-filtering company.

Sophos came up with its percentages by scanning spam messages received at e-mail accounts, or "honey pots," set up around the world. According to the report, Canada has managed to cut the amount of spam originating from its country by half, from 6.8 percent six months ago to 2.9 percent at present.

It also said "zombie" PCs, or computers exploited by a virus or hacker to automatically send junk mail, are delivering 40 percent of spam across the globe. "Many of the computers sending out spam are likely to have had their broadband Internet connections exploited by remote hackers," Cluley said.