Did 5G kill the IMSI catcher?

Washington, D.C. mobile traffic is probably the most spied in the world. Especially now when it's run by technological cavemen and overly confident techbros. Israeli, Russians, Chinese, French and everyone.

If you don't have a Faraday cage and cell site equipment, you're going to have a hard time verifying any of this. The modem is closed source, the SIM card is closed source, and various firmware blobs to make phones work are all closed source. I believe Qualcomm has debug interfaces on some chipsets, which might catch these messages, but verifying that they catch all use cases is impossible unless you have knowledge of the actual mechanism used (or usable) to activate the modem.

This is one of the reasons I'm hoping for the open source phone community to succeed. So far, the modem stack is usually proprietary (with hardware kill switches in the most paranoid phones), but it only takes a small group of Linux enthusiasts to actually catch the phone network in the act.

Of course, the trouble is that you'll need to be the target of government surveillance to be even at risk of any of this. If you're not a criminal or a human rights activist, the government is probably not pointing its secret spying equipment at you, and whatever criminal enterprise hacked its way into the carrier network won't either. If you are being tracked by either of those, I think developing open source modem firmware is probably the least of your concerns.

I honestly wouldn't be surprised if the standard was written to make this kind of surveillance possible and that any modem refusing to cooperate would be spec incompliant. You can read most of the 3GPP spec for free on sites like https://portal.3gpp.org/ but I don't have the time or interest to dig through the unreadable stream of abbreviations and industry terms to find out.

It's all rather pointless anyway when 5G and to an extend 4G can geolocate you about as well as GPS can, barring reflections and such.

This isn't true, there are major incidents related to IMSI-catchers going on globally right now. E.g. last week from Japan: https://newsonjapan.com/article/145466.php, https://commsrisk.com/amateur-detectives-find-numerous-fake-..., and mass arrests happening in Thailand related to the operation of them recently.

To see news related to them, search "Fake Base Stations" or "SMS Blaster", as this is how they're commonly referred to in the media now.

Other notable highlights from the last few years include: the news from Paris a few years ago where police detonated a car with an imsi-catcher in it because they thought it was a bomb, but actually the driver was being paid to send out sms spam via 2g downgrade attacks: https://commsrisk.com/paris-imsi-catcher-mistaken-for-bomb-w.... Also the attempt to disrupt the federal elections in the Phillippines using a kind of "SMS blaster" that takes advantage of unauthenticated emergency alert messages, so a step beyond the "classic" imsi catching attack that we haven't seen used in the wild before.

if you don't have an extra $400-900 and buy a cheaper android, you get to dial ##4636## (hn screws asterisks, look it up) them go into phone info, select each sim radio and change the drop down (and hopefully you know all the standards by all names to make the right choice. hint 5G is NR there)