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The ad software firm TubeMogul has uncovered a botnet ring that could be generating as much as $10 million a month in fraudulent video views, preying on advertisers like Nissan and Samsung. Like a traditional click-fraud network, the botnet works by hijacking computers with malware and sending them to generate false traffic for sites. But this network is more sophisticated, using tricks to make a single computer generate traffic that appears to come from thousands of different viewers. The network also targets ad cookie networks, visiting other sites to establish an advertiser-friendly background for the fake traffic.
http://www.theverge.com/2014/4/18/5628028/10-million-a-month-fraud-ring-preys-on-online-advertisers