Nov. 1, 2011 at 4:28 PM ET
In cybercrime's mug sheet of top offenders, the "Dirty Dozen" of nations responsible for relaying spam now includes five Asian nations, including South Korea, which had the biggest increase to become second only to the U.S.
As compiled by senior technology consultant Graham Cluley for Sophos' Naked Security blog, the list shows how Indonesia, Pakistan, Taiwan and Vietnam have stepped into notoriety since the fall of 2010.
Sophos' latest research reveals that even as the U.S. remains the single worst offender with 11.3 percent, Asian nations now contribute "more than half of all spam messages now being relayed via the continent" at 50.1 percent. Just a year ago, Asia was responsible for less than a third of that global figure (30 percent) and at the beginning of the year, it was only 35.1 percent.
South Korea leap-frogged five places to come in second to the U.S., contributing 9.6 percent of all global spam emails. India dropped to third place with 8.8 percent.
"The spam that attempts to smash its way into users' email accounts can vary from being annoying adverts to downright malicious attacks. In the worst cases, a spam message might be designed to infect your computer with a Trojan horse or phish your banking credentials," said Cluley. "These latest statistics suggest that, as more people get online in Asia, they are not taking the right measures to protect their computers from infection, which results in the growth of botnets."
He adds, "The vast majority of spam emails are distributed by botnets — networks of infected machines (zombies) which are under the control of spammers."
Users can unwittingly become part of these botnets through simple neglect in not keeping anti-virus software and security patches up-to-date. They can also fall into traps set by clicking on suspicious links and attachments.
The recently released Microsoft Security Intelligence Report revealed a drop in spam messages blocked by Microsoft's Forefront Online Protection for Exchange service, used by thousands of enterprise customers. In July 2010, 89.2 billion messages were blocked and a year later, that was down to 25 billion, mostly due in part to taking down two major botnets.
(Msnbc.com is a joint venture of Microsoft and NBC Universal.)
While Asian nations have increased in their infection numbers, European countries have decreased their spam by more than 10 percent than it was a year ago.