According to Blue Coat's 2011 Web Security Report, U.S. users spend about 906 million hours on social networks each month -- more than twice as many as they spend on online games (407 million hours) and email (329 million).
Attackers recognize this trend and are responding in kind, the study says.
"Social network phishing and click-jacking attacks were the two most common types of attacks through social networks in 2010," according to Blue Coat. "The shift of phishing attacks to social networks is particularly driven by the attempt to obtain user credentials that can also provide access to banking, financial, and other online accounts that use shared passwords."
Webmail was the 17th most requested Web category for 2010, falling from ninth in 2009, and fifth in 2008. "This ongoing decline in popularity is driven by an overwhelming shift to social networking as the communication platform of choice for Internet users," the report states.
Attackers also are moving their launch infrastructures from free domains to known sites with trusted reputations and acceptable use category ratings, Blue Coat says.
"Before, we saw sort of a shotgun approach where attackers would try to infect any legitimate sites they could," says Tom Clare, senior director of product marketing at Blue Coat. "Now we're seeing more spear-type attacks on legitimate sites that will be allowed under acceptable use policies."
Online storage and open/mixed content sites -- which ranked second and sixth, respectively, on the list of sites hosting malware -- saw the fastest growth in 2010, according to the report. Both of these categories typically fall within acceptable use policies for most companies.
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