[DyslexicAtheist]

> For two months last year, researchers at the University of Washington paid drivers of an unidentified ridesharing service to keep custom-made sensors in the trunks of their cars, converting those vehicles into mobile cellular data collectors. They used the results to map out practically every cell tower in the cities of Seattle and Milwaukee—along with at least two anomalous transmitters they believe were likely stingrays, located at the Seattle office of the US Customs and Immigration Service, and the Seattle-Tacoma Airport.

source: https://www.wired.com/2017/06/researchers-use-rideshares-sni...

> At Trudeau airport, Radio-Canada detected the catcher's presence through the use of a CryptoPhone — a cellphone look-alike that emits red alerts when a fake antenna tries to catch its signal. Several red alerts were received, throughout the afternoon and early evening, in the section of the airport for U.S. departures.

source: https://www.cbc.ca/news/canada/montreal/trudeau-airport-spyi...

> The devices are operated out of at least five U.S. airports, "covering most of the U.S. population". It is unclear whether the U.S. Marshals Service requests court orders to use the devices.

source: https://en.wikipedia.org/wiki/Dirtbox_(cell_phone)

[mrandish]

That's super interesting. Those are international departure airports. I wonder if what they're doing is sniffing for phone numbers of interest showing up in the international terminal indicating a 'person of interest' is trying to leave or arrive. I assume people trying to leave or enter the country without permission might have false ID and a false name on their ticket but they probably don't think about changing their phone number.

Once you have a number pop up on the Stingray you distribute that person's photo to all the border agents.

[fooey]

Or the reverse.

Since airports are one of the very few places where you can positively identify a certain person was there at a certain time, you can combine a passenger list with a device list to get some soft matches to previously unlinked devices.

Combine that linked metadata with other dragnet metadata, and you're going to learn a lot.

[harshreality]

That should mean they can also correlate who picks up or drops off whom... so even if you aren't traveling, you're in their database linked to someone who is.

[t34543]

Combined with APNR and patterns over time, yes.

[FPGAhacker]

This makes a lot of sense to me.

[auiya]

Probably used for things like terrorist watch lists, national security ventures, etc... highly doubtful it's used for domestic law enforcement purposes. The US wants to know when foreign nationals of interest attempt to enter/exit the country.

[t34543]

Very naive of you to think that.