
The report, which covers Q4 2005, found that the US was responsible for relaying 24.5 percent of all spam closely followed by China and Hong Kong with 22.3 percent.
Well below this South Korea racked up 9.7 percent, France 5.0 percent and Canada 3.0 percent.
Australia’s ranking at 23rd in the list was good news, according to Sophos head of technology Paul Ducklin.
“Infection rates from malware seem to be much lower in Australia than they are, for example, in North America, even when population differences are taken into account,” Ducklin said in a statement. “So there are fewer zombies in Australia from which spam can be sent — whether to users in Australia or abroad."
The report also found that the vast majority of spam was now being relayed by zombie computers hijacked by trojan horses, worms and viruses under the control of hackers.
“The fact that the dirty dozen is comprised of nations from four different continents gives an indication as to the nature of the spam problem,” it said. “ Zombie computers — responsible for relaying more than 60 percent of the world's spam — can allow spammers to escape country-specific legislation, as they no longer have to be located in the same country as the spamming machines they operate.”