Cyber attacks that infect web pages with malicious codes have tripled in 2008, according to Sophos.
The security vendor's Security Threat Report 2009 says there's now an attack on a web page every four and a half seconds - that's three times the rate reported in 2007.
The report also revealed that five times more hoax emails with dangerous attachments are being sent than at the start of the year.
Sophos said the US is responsible for more spam than any other country in the world, relaying 17.5 percent of all unsolicited email. The US also hosts the most malware, with 37 percent being hosted by American companies.
"Not only is the US relaying the most spam because too many of its computers have been compromised and are under the control of hackers, but it's also carrying the most malicious web pages, " said Graham Cluley, senior technology consultant for Sophos.
"The last year proved beyond doubt that internet hacking gangs are organised like never before, often working across borders to steal money and data from unsuspecting users. The volume of attacks has increased, with hackers using automated systems to break into vulnerable websites or generate new variants of their malware.
"As we enter 2009 we are not expecting to see these assaults diminish. As economies begin to enter recession it will be more important than ever for individuals and businesses to ensure that they are on guard against internet attack."