The Electronic Frontier Foundation has released an open source project called Rayhunter. It is designed to run on an inexpensive (~$20) mobile hotspot and look for signs of mobile spying devices called cell-site simulators. Also known as Stingrays or IMSI catchers, they masquerade as legitimate cellphone towers, tricking phones w/in a certain radius into connecting to the device rather than a tower.

https://www.eff.org/deeplinks/2025/03/meet-rayhunter-new-open-source-tool-eff-detect-cellular-spying

Meet Rayhunter: A New Open Source Tool from EFF to Detect Cellular Spying

Rayhunter is a new open source tool we’ve created that runs off an affordable mobile hotspot that we hope empowers everyone, regardless of technical skill, to help search out cell-site simulators (CSS) around the world.

Electronic Frontier Foundation
@briankrebs I don not need one of these but WOW am I glad this device exists!
@feoh @briankrebs You don't want to know if someone's spoofing your cell connection?

@crazyeddie

You mis-understand.

There is a lmit to how many incursions one can ward ones self against every minute of every day.

I treat cellular comms like broadcast anyway, and so as I said, while I am VERY glad this exists, I do not feel the need to carry one at all times.