The report also notes criminals are poisoning search results and using search engine optimization (SEO) and link-farming techniques to deliver malware.

"These efforts have shifted from free domains to hacked sites with reputable domains in an effort to be better hidden from defenses," the report said.

Criminals are increasingly targeting the most popular web destinations

Historically, malware has been hidden on sites that would traditionally be blocked by any good filtering software. But the Blue Coat research finds online storage sites, which include photo-sharing sites like Flickr, and open/mixed content sites, such istockphoto and YouTube, saw the fastest growth in malware activity in 2010.

"The number of new online storage sites hosting malware increased 13 percent while the number of new open/mixed content sites hosting malware increased 29 percent. Both of these categories typically fall within acceptable use policies for most companies," the report claims.