There used to be a very handy Android app, now booted off the Google Market, called "GSM Spy Finder" which worked on MediaTek SoCs.<p><a href="https://apkplz.net/app/kz.galan.antispy" rel="nofollow">https://apkplz.net/app/kz.galan.antispy</a>
In case anyone else is wondering what an IMSI-Catcher is, let me save you a google:<p>"An international mobile subscriber identity-catcher, or IMSI-catcher, is a telephone eavesdropping device used for intercepting mobile phone traffic and tracking location data of mobile phone users."<p>1 - <a href="https://en.wikipedia.org/wiki/IMSI-catcher" rel="nofollow">https://en.wikipedia.org/wiki/IMSI-catcher</a>
Is it just me that looks at the equipment photo, and thinks - you're using an inverter to convert 12VDC to 120VAC, then a couple of wall plug transformers to convert that back down to low-voltage DC - why don't you just use a DC regulator?
Ooh. New project for today. Deploy this locally and figure out how to make this a public service where people can run their devices and the data is uploaded to a central database in real-ish time so people can see suspect changes.<p>EDIT: This should have a 2017 tag, as the code is 4 years old and I assume the same is true for the website.
It is much easier (and more often done) to implement a solution for a static position. Many embassies and other highly sensitive locations have these, commercially available, installations.<p>We used to build them for fun (no profit) many moons ago.<p>Basically what you do is place a couple of (1, 2 or whatever) sensors (we used to use these Motorola C123 with osmocom) and just keep taps on signal strength and antenna ID over time, and inspect changes.
The German government has just published a paper on the requirement for telecom operators to ensure LEA continue to be able to _covertly_ intercept traffic in 5G: "Ensuring Undetected use of the IMSI Catcher", the paper which is in German (<a href="https://posteo.de/FormulierungshilfeBMI.pdf" rel="nofollow">https://posteo.de/FormulierungshilfeBMI.pdf</a>) reads:<p><i>" > Mobile network operators must ensure security authorities can use IMSI Catchers without the end user becoming aware of this. According to the TKG-E, mobile operators must continue to allow IMSI catchers in accordance with statutory investigative measures. Until now, it's unnecessary for operators to act so that members of the Security authorities can use IMSI-Catchers, as they "simply" pretend to be a base station. In new mobile networks, devices brought into the network must be actively "accepted" by the network and otherwise cannot be used. As a result, it will no longer be possible to insert IMSI catchers of "previous design" into the new networks. We acknowledge that in the future unauthorised persons, such as foreign intelligence services can no longer use them. At the same time, it will no longer be possible for German security authorities to use an IMSI catcher without the cooperation of the mobile operator. The necessary regulations for the participation of the mobile operator are already included in the draft TKG, but the necessary addition is missing that the introduction of an IMSI catcher by security authorities may not be known to the end user."</i><p>Most people will think this is a fringe scenario which will never affect them. But they are very common in international airports:<p><i>> 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.</i><p><a href="https://www.cbc.ca/news/canada/montreal/trudeau-airport-spying-1.4055803" rel="nofollow">https://www.cbc.ca/news/canada/montreal/trudeau-airport-spyi...</a><p><i>> 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.</i><p><a href="https://www.wired.com/2017/06/researchers-use-rideshares-sniff-stingray-locations/" rel="nofollow">https://www.wired.com/2017/06/researchers-use-rideshares-sni...</a><p><i>> 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.</i><p>source: <a href="https://en.wikipedia.org/wiki/Dirtbox_(cell_phone)" rel="nofollow">https://en.wikipedia.org/wiki/Dirtbox_(cell_phone)</a><p>For a "modern" take on this subject (info relevant to 3G is outdated unless they do a downgrade attack on you first), see this article and the linked videos that go into the issues LEO face with 4G/5G and the "crocodile hunter" software that is an EFF project to identify them: <a href="https://www.pcmag.com/news/police-spying-on-your-phone-ask-crocodile-hunter" rel="nofollow">https://www.pcmag.com/news/police-spying-on-your-phone-ask-c...</a>