The majority of spam is sent via botnets of hijacked systems in the homes and offices of innocent users who are unaware of their role in the global spam problem. Botnets represent a valuable resource for hackers, as do the hosting services that provide cybercriminals with server space and bandwidth to host their websites and control centers. Webmail also continues to be a vehicle for spammers despite the efforts of webmail providers to ensure their users are not automated bots.
The US once again leads the field of spam-relaying countries, contributing 13.81% of the world's spam traffic in the first half of 2010. The new "Tiger" economies of India and Brazil are the only others to break the 5% barrier in the last six months, with their massive populations coming online and clearly lacking the protection needed to keep their systems free from spamming malware.
But with more mature major economic powers such as South Korea, Germany, France and the UK also featuring in the top 10, it's clear that wealth and technological advancement are no guarantee of safety.
Spam by continent
Source: SophosLabs