Domain Spoofing: Ads.Txt Filtering Out Imposter Sites

17 May 2017

Programmatic buyers on the open exchange who think they’re purchasing inventory from ESPN or The New York Times often end up buying from imposter sites instead. At times, the amount of misrepresented inventory in the marketplace can dwarf the legitimate inventory sold by brand-name publishers.

The practice, domain spoofing, will become much harder to carry out thanks to a tech tool developed by the IAB Tech Lab called ads.txt. After a 30-day public comment period ending June 19, buyers will be able to use ads.txt data to filter out unauthorized sellers of a publisher’s inventory.

“This is a very elegant, simple solution,” said Alanna Gombert, GM of IAB Tech Lab.

Publishers put a text file on their site listing all the exchanges they work with. Buyers send web crawlers to scour publishers’ sites and collect the lists. DSPs can then choose to filter inventory so buyers only go through those listed exchanges.

“We can make sure the spend intended for that publisher actually goes to that publisher,” said Scott Spencer, Google’s global director of product management for sustainable ads. Google participated in developing the ads.txt initiative.

Ads.txt would filter out impressions pretending to be from a premium publisher, as well as any unauthorized reselling of a publisher’s inventory.

The project has been in the works since the end of 2016, spurred by increased marketer and industry awareness of fraud and new threats like Methbot, which spoofed 6,111 premium domains and 250,267 distinct URLs.

“Virtually every premium publisher had been spoofed by that botnet,” said Mike Zaneis, president and CEO of the Trustworthy Accountability Group “That’s a scary proposition for any premium publisher.”

Buyers who use whitelists, such as JPMorgan Chase, can’t tell if some sites on their lists are masquerading as a trusted publisher. Ads.txt will close this gap.

“It can’t be that there are 300 different paths to purchasing New York Times inventory. It can’t be unlimited,” Zaneis said. “A lot of that traffic must be misrepresented.”

The IAB Tech Lab could not quantify how much inventory is misrepresented.

Google said that because fraud levels fluctuate, calculating the impact of domain spoofing can be difficult.

“No one knows for sure exactly how much invalid traffic there is,” Spencer said. “It ebbs and flows over time.”

As buyers adopt ads.txt, it would be logical to see ads increase their impact. And the promise of a more trusted marketplace could woo back buyers who have recently pulled spend over concerns about fraud and brand safety.

“If you weed out fraud from the equation, performance will hopefully go up because you are buying real inventory,” Gombert said. “The holy grail now is to make sure you are buying a real user and a real site.”

Sellers could see CPMs rise as supply goes down. And a clearly labeled marketplace would allow buyers to evaluate publishers more clearly. Because buying misrepresented inventory is so common, many publishers constantly field questions from buyers with misperceptions of the publisher based on their evaluation of faked inventory.

But ads.txt doesn’t cover all types of inventory reselling and misrepresentation. Ads.txt doesn’t specify if a vendor is authorized to seller banner ads or video ads, Gombert pointed out, leaving open a loophole for in-banner video arbitrageurs that represent display inventory as video inventory.

“Display-to-video arbitrage is not necessarily solved by this, but it starts the conversation,” Gombert said.

Adding markers to include inventory type could become part of further iterations of ads.txt, Gombert said. For now, it’s taking public comment on the tool before it goes live.

Source: Sarah Sluis, Ad Exchanger