New research has uncovered a bot farm that is estimated to be fraudulently stealing millions in revenue from online video advertising companies.

Dubbed “Methbot” by New York-based security firm White Ops because of references to meth in the bot’s code, the Russian-run bot uses an army of automated web browsers run from fraudulently acquired IP addresses. They deliver as many as 300 million fake video ad plays a day, tricking advertisers into paying for views that were never seen by humans.

The bot uses falsified websites designed to look like premium publisher inventory to trick advertisers, with more than 6,000 premium domains being targeted and spoofed. White Ops estimates that Methbot generates a staggering $3 million to $5 million in fraudulent revenue per day, making it the largest ever fraudulent ad bot discovered.

State-sponsored actors are not believed to be behind the bot. “We really see no signs of state sponsorship, it looks to us like this is really a private criminal group,” White Ops Chief Executive Officer Michael Tiffany told CNBC. “They’re just badasses.”

Tiffany added that the people behind the scam are likely to have a deep understanding of the video advertising industry, noting that Methbot ” shows an incredible, absolutely insider’s mastery of digital advertising … it requires multiple skills.”

According to White Ops, Methbot takes advantage of the way the online advertising market matches media companies to advertisers to avoid being detected. “The online advertising market depends on an automated auction system in order to match media companies with advertisers,” the report noted. “Advertisers hire a vast array of ad buyers to purchase advertising time on websites across the Internet. That process has been automated through software exchanges that match buyers and sellers of online video, with hundreds of transactions taking place in fractions of seconds.”

That’s the process that is being attacked, the report said: “The Methbot group offers fake advertising inventory into the system, and then generates phony views of the ads in an effort to collect money from the unwitting ad buyers.”

A full copy of the report is available here.

Image credit: craigdietrich/Flickr/CC by 2.0