Potentially this is where the likes of the PinePhone should thrive [1].
As well as the methods suggested, you could have full disk encryption and just have the phone switch off if it suspects any shenanigans. If you want, it could still boot into an OS, but it just denies knowing about the encrypted disk. Done right, the image itself could be difficult to discern from something like a corrupted video file.
> Your Risks at a Protest
In addition, your SIM (likely traceable to you, especially if you have it) will be auto-connecting to their temporary telecom system (i.e. Stingray [2]), where they can find out the following:
1. That you were nearby to the event.
2. A tonne of operations available via the modem [3].
3. If you speak to somebody locally (as part of the routing).
4. Shift your connection down to 2G/3G where it is easier to hack [4].
I think each person needs to consider their security model.
Regarding #2, I thought AT commands were something you could send to your modem from your attached device. I'm not aware that they could be sent to a modem by another remote modem over the network link. Is that also possible?
You are correct, it's just there to give you an idea of the capabilities of the modem, what sorts of information it holds and what the cell tower may query.
As well as the methods suggested, you could have full disk encryption and just have the phone switch off if it suspects any shenanigans. If you want, it could still boot into an OS, but it just denies knowing about the encrypted disk. Done right, the image itself could be difficult to discern from something like a corrupted video file.
> Your Risks at a Protest
In addition, your SIM (likely traceable to you, especially if you have it) will be auto-connecting to their temporary telecom system (i.e. Stingray [2]), where they can find out the following:
1. That you were nearby to the event.
2. A tonne of operations available via the modem [3].
3. If you speak to somebody locally (as part of the routing).
4. Shift your connection down to 2G/3G where it is easier to hack [4].
I think each person needs to consider their security model.
[1] https://pine64.org/devices/pinephone/
[2] https://en.wikipedia.org/wiki/Stingray_phone_tracker
[3] https://www.electronicsforu.com/special/cool-stuff-misc/gsm-...
[4] https://www.eff.org/deeplinks/2020/06/your-phone-vulnerable-...