The study says it has found apps available on app sites such as 's App Store or Play, as well as third-party app stores, which rapidly load hidden ads – as many as 20 a minute.
When the apps are in use, only 10%-20% of ads are displayed to the user, but ads will also be loaded as background processes on the device, dropping viewability to zero. Forensiq even observed some apps loading ads without being opened.
Other apps were found to generate random clicks on ads, a tactic which may be designed to move the needle on performance metrics such as click through rate.
Over a 10-day period, Forensiq flagged 12 million devices, which potentially had apps engaging in this kind of fraud.
Forensiq also tracked 16.2 billion daily mobile in-app impressions for 30 days, flagging 2,857 apps on Android, 900 on iOS and 1,404 on Windows as displaying characteristics of fraudulent activity.
Forensiq estimates that the cost to advertisers could reach $1 billion in 2015.
When Forensiq downloaded and observed the behaviour of some of these apps, they found ads for the likes of , , , and Mercedes Benz.
Speaking to Brand Republic, Mike Andrews, chief scientist at Forensiq explained how difficult it is for app stores to identify apps with malicious code.
Techniques include needlessly complicated code, simple code that hides complexity, and advanced techniques that can detect when code is being monitored and "play nice", then change behaviour when it's in the wild.
Andrews said: "Google and Apple and all these other app stores have a very tough problem that they’re trying to solve.
"In principle it’s impossible to solve, but in practice they can certainly get better and better at recognizing techniques."
Apple, Google and Windows did not respond to requests for comment.
Forensiq's chief technology officer Matt Vella offered one solution: "Our algorithms can identify these applications in real time and advise, in real time, basically buy or don’t buy."
The can be downloaded from Forensiq's website.