Nearly three-quarters of the top 100 sites on the web host malicious code or redirect users to malicious sites, according to new research from content security provider Websense.
The Websense Security Labs State of Internet Security Q3-Q4 2008 (PDF) report said that the figures represent a 16 per cent increase over the previous six-month period.
Websense also found an increase of 46 per cent in the number of malicious sites from 1 January 2008 to 1 January 2009.
"Spammers are increasingly using links to malicious web sites and spam sites in their email campaigns to lure users and evade security systems that lack web intelligence," said Websense chief technology officer Dan Hubbard.
"We are also seeing an increase in cyber criminals taking advantage of the growing number of Web 2.0 properties that allow user generated content."
Hackers are frequently inserting links and iFrames into sites to direct users to malicious and compromised sites, he added.
The report also found an increase in the number of blended email and web threats. Just over 90 per cent of all unwanted emails in circulation in the second half of 2008 contained links to spam sites and/or malicious sites, an increase of around six per cent.
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