US Authorities Use Advertising Identity Numbers to Track Devices

Police and other US law enforcement agencies are using a low-cost tool that allows them to track mobile devices even in communities of less than 100,000 people, according to the Associated Press (AP) and the Electronic Frontier Foundation (EFF). The system in question is called Fog Reveal.

US authorities have been using Fog Reveal since at least 2018, using the resource to investigate predominantly serious crimes such as murders and the Capitol riots. The tool was developed by Virginia-based Fog Data Science. It can be used without a warrant and can be accessed instantly, unlike a formal request to Apple or Google, which in some cases have to wait weeks for a response to identify the location of a mobile device.

Fog Reveal uses advertising ID numbers that are unique to each mobile device in order to track users’ location. The data is fed into the system by aggregators that receive it from apps that provide targeted ads based on location and user interests, such as Waze and Starbucks.  However, the coffee chain and the Google-owned company deny that they gave their partners consent to share data with Fog Reveal.

Information about the service was obtained by EFF employees, who then passed the material on to AP. EFF's special adviser, Bennet Cyphers, describes the tool as "sort of a mass surveillance program on a budget." It costs from $7!500 a year, and some agencies buy one for several departments to save money. AP reporters examined data from the GovSpend website and found that Fog had sold some 40 contracts to two dozen government agencies, whose employees, in turn, compiled several hundred searches on a database of 250 million devices.

Fog Reveal does not provide names, but authorities are always able to analyse people's "patterns-of-life.” For example, to establish where a person usually goes on their way to work. The service provides an archive of geo-positioning for each site over the past 180 days, although Fog managing partner Matthew Broderick admitted that the tool "has a three year reach back."

Authorities have applied Fog Reveal over the past few years with varying degrees of success. Washington County prosecutor Kevin Metcalf acknowledged using the system in circumstances where urgent action was required, such as murder investigations or searches for missing children. On privacy issues, he said:

I think people are going to have to make a decision on whether we want all this free technology, we want all this free stuff, we want all the selfies. But we can't have that and at the same time say, 'I'm a private person, so you can't look at any of that'.