Brands are being warned of a highly sophisticated and growing bot threat that generates fake browser data and fabricated URLs to steal advertisers’ media spend.

The threat, dubbed the 404bot, works through domain spoofing – appearing to use a brand’s domain to impersonate that company. It does this at the browser level, digital ad verification firm Integral Ad Science (IAS) warns.

The bot has been active since 2018, says IAS, but as its threat is growing, the warning has been issued. It is thought to have affected more than 1.5 billion video ads and to have so far cost the industry $15 million.

The bot’s sophistication lies in the fact that it exploits the very defence established to protect ad buyers from bogus sellers – the Authorised Digital Sellers initiative, known as Ads.txt. IAS warns that the 404bot is able to generate spoof URLs not easily detectable to the human eye, and is able to slip through multiple preventative measures.

Up to now, says IAS, the introduction of Ads.txt has brought about a big reduction in ad fraud, but criminals’ attack methods are constantly evolving and the 404bot exploits unaudited Ads.txt files. It has hit a large range of publishers’ domains, says IAS, high and low profile. Many victims, though, have one thing in common – large Ads.txt lists.

“Publishers have done an excellent job in implementing Ads.txt but what we are learning from this bot is that it is crucial to continuously audit and update Ads.txt files,” said Evgeny Shmelkov, Head of the IAS Threat Lab.

The big rise in digital ad fraud is not only benefitting criminals, however, it’s also fuelling investment growth for the good guys.

Mobile marketing and ad fraud prevention platform App Samurai has announced it has secured an investment of Series A funding of $2.4 million, led by 212 Ventures, and co-invested by Collective Spark, 500 Startups and Degerhan Usluel.

The money takes the company’s total investment to-date to $4.6 million. The cash will be used to further develop the group’s product range and global expansion.

Last year, Interceptd, App Samurai’s ad-fraud prevention solution, blocked more than $10 million of potentially wasted ad spending, the company says, and the business achieved 240% growth in the same year.

Sourced from IAS, TechCrunch; additional content by WARC staff