US, China ranked as top hosts of PC security threats

The US and China hosted nearly two-thirds of spam, viruses and other computer security threats delivered around the world last year, a report said on Monday.

Computer security firm Sophos said that 34.2 percent of the so-called malware last year originated from the US, with 31 percent from China.

Russia was third, accounting for 9.5 percent of the threats, the company said.

"The enormous number of computers based in North America probably makes it no surprise that the US heads the list, and is hosting over a third of all Web sites containing malicious code," the report said.

Sophos said it identified 207,684 different threats, ranging from spam, viruses and "trojans" that download programs to infect computers, to "ransomware" designed to "kidnap"data by encrypting it and then providing the password once a ransom has been paid.

The report said 90 percent of all spam is now relayed from "zombie computers" infected with some kind of malicious code.

Sophos said its "dirty dozen" list of worst spam-relaying nations was again headed by the US, accounting 22 percent of the spam sent worldwide.

China was second with 15.9 percent, followed by South Korea (7.4 percent), France (5.4 percent), Spain (5.1 percent), Poland (4.5 percent), Brazil (3.5 percent), Italy (3.2 percent), Germany (3.0 percent), Britain (1.9 percent) and Russia and Taiwan (with 1.8 percent each).

Sophos noted, however, that because spam is mostly relayed from zombie computers, the relaying PC does not need to be based in the same country as the computers used to send the spam.

Sophos predicts that this year is likely to see a significant shift away from the use of e-mail security threats, with cyber criminals instead looking to infect computers through contaminated Web sites.

"SophosLabs is currently uncovering an average of 5,000 new URLs hosting malicious code each day," the report said.