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It sure is. Look up the SnoopSnitch project, https://opensource.srlabs.de/projects/snoopsnitch.

It will alert you if your phone connects to a fake cell tower aka stingray device.

Yes, unfortunately in this under-caffeinated moment I can't recall the right google search terms. As I recall, there are a small number of root-able Androids that are suitable for pairing with a RasPi, which together with suitable software gives you a stingray detector.

Something like this, perhaps? https://hackaday.io/project/15711-raspberry-pi-stingray-dete...

Looks like a pretty standard software defined radio reciever that profiles local cell towers so as to notice when a new, lower power (local) tower is put up, which you can then assume is some kind of stingray type device. Looks pretty easy to set up as well.

A low power cell tower might simply be a legitimate micro-cell, such as in a home or office where ordinary tower reception is very poor.

Actually I fuzzily recall seeing homebrewed IMSI-catcher and IMSI-catcher-catcher projects.

DHS has apparently detected stringrays of unknown origin in DC[1], so it is definitely possible.

[1] https://wapo.st/2JhRnwO?tid=ss_tw&utm_term=.b7ba020e94ee