In the movies, people on the run are often hunted down because of their cell phones. There are countless scenes where expensive smartphones are smashed to bits, or dropped in rivers, to evade capture by nefarious government operatives or well-equipped mobsters.
Hopefully you’re not in that situation. But if you were, do you really need to go that far? We asked the experts what information your cell phone is really broadcasting about you, how to protect yourself, and what it would take to truly go off the grid.
The simple options don’t work
If you suspected your phone were being tracked and wanted to start covering your tracks without snapping it in half, your first bet might be to simply turn on airplane mode. That won’t cut it.
“Every phone has two operating systems,” explains Gary S. Miliefsky, CEO of SnoopWall, “One that connects to cellular networks, and one that interfaces with the consumer. Airplane mode may only disable features in the consumer facing operating system, such as Android or iOS, but not in the OS used between the phone and the carrier network. A phone may be giving out a ‘ping’ and you’d never know it.”
Communicating at all with a cell tower could expose you
It doesn’t even need to be sending out GPS coordinates — communicating at all with a cell tower could expose you. By comparing the signal strength of your cell phone on multiple cell towers, someone looking for you can approximate your location with triangulation. This requires access to data from your mobile network, which should keep it out of reach for criminals, but carriers can be compelled to provide that data to law-enforcement agencies.
So how about removing the SIM card?
“Removing the SIM may work to stop most cyber criminals, but every phone has a built-in feature set of identifiers that may be detected via tools like Stingray devices now used by the police and military, as well as fake 2G cell towers put up by the NSA,” Gary explains, “Forcing a phone to 2G means no encryption and it’s easily detected and tracked.”
Stingrays are also known as cell-site simulators, or IMSI catchers. They mimic cell phone towers and send out signals that can trick your cell phone into replying with your location and data that can be used to identify you. And they’re surprisingly widely used.
The American Civil Liberties Union has a map and list of federal agencies known to use cell-site simulators, which includes the FBI, the DEA, the Secret Service, the NSA, the U.S. Army, Navy, Marshals Service, Marine Corps, National Guard, and many more. For obvious reasons, it’s not an exhaustive list.
What about Wi-Fi?
At short range, you can be tracked by Wi-Fi. Every time you turn Wi-Fi on, your phone is sending out a signal that includes your unique MAC address, which is kind of like a fingerprint for digital devices. This kind of technology is already being used by stores to track your movements. It’s not ideal for surveillance, because of the limited range, but if someone has obtained your MAC address it could be used to deduce something like when you enter or leave a specific building.