Botnets still roam large, with the USA relaying the most spam in Sophos' latest global "Dirty Dozen" report.
Typically, hackers use compromised PCs to relay spam, building large botnets to send out malicious links or for other criminal activities, for example DDoS attacks. Sophos calls compromised computers zombies.
For January through to March this year, the USA topped the list of spam relaying countries with 13.7 percent of messages sent. It was followed by India at 7.1 percent, while Russia and Brazil came in third and fourth place with 6.6 and 6.4 percent respectively.
South Korea came in fifth place with 3.8 percent, while the UK was guilty of contributing 3.2 percent.
It was a tie for seventh place between Italy and France landing 3.1 percent each, while Spain came in at nine with 2.8 percent. Germany had tenth place with 2.6 percent.
Bringing up the rear were Romania and Poland which came in at 11 and 12 in the charts with 2.5 percent and 2.3 percent respectively.
Financially-motivated criminals, says Sophos, continue to control compromised computers not just to launch spam campaigns, but also for identity theft and to seize bank account information.
Sophos says it has identified spam from 229 countries globally in the first quarter of this year alone.