In 2017, a senior French investigator returning from Milipol, the major biennial trade fair dedicated to state security, had something to confide. Shocked, he informed us he had been approached on the sidelines of the event by "an Israeli company," whose name he did not wish to disclose, that tried to sell him a geolocation tool using advertising data collected from mobile phones.
Nearly a decade later, what once seemed like science fiction now drives a well-established industry. Today, companies offer services in advertising intelligence (Adint): By collecting the geolocation data of millions of phones worldwide from advertising markets, they promise intelligence or law enforcement agencies the ability to track individuals to within a few meters.
According to Le Monde's analysis, around 15 companies, at least, now propose such services. Most are based in Israel and were founded by former members of the country's intelligence services or military. Others are based in Europe and the United States. Their raw material is the advertising data exchanged and resold on online marketplaces, collected by thousands of ordinary apps, such as games or weather apps, supposedly for advertising purposes.
Adint tools are in increasing demand. More and more companies in the sector have started showcasing them at industry trade shows and specialized conferences. According to US business magazine Forbes, US immigration police ICE recently purchased an Adint tool for $5 million (€4.3 million). Such tools have been viewed and promoted as alternatives to other tracking methods, which are either more cumbersome or increasingly ineffective. However, Adint surveillance tools, which operate under lax or even nonexistent regulation, raise major concerns about personal freedoms, since any country or institution can use them against any phone anywhere in the world.
Article doesn't really go into the "how." Specifically what the "advertising ID" is, and how it's attached to a location.