The United States remains the top hot spot for malware hosting and spam-relaying worldwide. According to Sophos' Security Threat Report 2007, the US hosts an estimated 34.2% of the sites hosting web-based malware at a global level, during 2006. China is runner up hosting 31% of the web-based malware and Russia come in third place with 9.5%.

"The US remains a hot spot for online criminal activity, and despite authorities' continued efforts to clamp down on cyber crime, too many US-hosted websites still have lax security measures in place," said Carole Theriault, senior security consultant for Sophos. "Given the effectiveness of web-based attacks, web hosting companies in the US and elsewhere need to step up their policing of published content, and ensure that malicious code is quickly removed, before innocent users get hit."

But the United States is also the topmost presence in a list of the worst spam-relaying nations worldwide, on top of hosting the largest volume of malicious websites. In 2006, the US has relayed 22% of all the global spam. China plus Hong Kong account for 15.9% of the relayed global spam in the past year while South Korea is in third place with 7.4%.

"Sophos experts note that up to 90% of all spam is now relayed from zombie computers, hijacked by Trojan horses, worms and viruses under the control of hackers. This means that they do not need to be based in the same country as the computers being used to send the spam," added Sophos.