A huge online advertising scam has been exposed that could be costing businesses, primarily in the U.S., almost $1.3 million a day.

Over the past eight weeks, thousands of publishers have been subject to bots creating fake versions of their websites, a technique called "domain spoofing," according to a paper published Wednesday by ad technology company Adform.

Brands inadvertently bought advertising space on these fake sites via ad exchanges, promotions that were seen by computers not humans, meaning that advertisers wasted money and publishers missed out on ad dollars.

Adform suggests that this new bot, dubbed "HyphBot," is three to four times the size of the Methbot scam discovered by White Ops in December 2016. Methbot was said to originate in Russia and used a network of bots to fake views of as many as 300 million video ads per day.

Adform estimates that HyphBot cost businesses between $262,000 and $1.28 million a day, adding that clients using its platform were protected, costing them less than $1,000 a month.