CYBERSPACE – Web-based advertising for mainstream companies has dethroned porn as the king of mobile malware distribution, according to a new report released Wednesday by security firm Blue Coat.

After analyzing data from more than 75 million users globally, the firm published the following statistics:

• Ad clicks represent about 12 percent of requested mobile content but about 20 percent of mobile malware encounters.
• The rate of advertising-related malware encounters has more than tripled since November 2012, when 5.7 percent of mobile users stumbled onto malware as a consequence of ad clicks. At that time, ads represented the No. 4 delivery method.
• Porn accounts for only 1 percent of mobile viewing but 16 percent of mobile attacks — down from more than 22 percent in November 2012, when porn ranked No. 1 among mobile malware distribution channels.
• Blue Coat’s February stats ranked porn’s threat level third, behind advertising and mobile games.

A Blue Coat spokesman said the company finds the trend alarming, not least because “malvertising” has infiltrated major global ad networks that also serve legitimate ads. Because the overall display of and engagement with mobile advertising is increasing rapidly, consumers often find it difficult to tell legitimate ads from malicious ones.

“The rise of malvertising as a leading attack vector mimics the rise of web ad traffic on mobile devices,” the Blue Coat report noted. “This is a largely unregulated network of ad servers that can easily be tricked into serving malicious ads unknowingly.”

Moreover, as recreational use of mobile devices increases, more cybercriminals will move into the space, according to the report. Activities like shopping, movie viewing, reading and game-playing now occupy about 12 percent of the average user’s mobile time, providing a large audience for advertisers and, consequently, fertile ground for scams.

Scammers “work like a business,” Sasi Murthy, vice president of product marketing security for Blue Coat, told NBC News. “They’re focused on low investment and high return, so they will go where the activity is.”