Comment by rixed
16 days ago
I'm not into bitcoins nor physical wallets, but I'm guessing those are not supposed to attach any gsm network ever. Isn't that trivial to detect, even without opening a device, that something inside is attaching the gsm network? Those are pretty strong signals in a well defined tiny range of frequency, after all.
(Not so long ago you could hear them talk with the towers through regular home speakers.)
You could only realistically detect this in a lab.
You need to actively listen at multiple frequencies at the same time (gsm/lte/5g have many different bands, + wifi/bt at 2.4/5/6 ghz and their bands). And you need to remove interference from all other devices to conclude that signal is coming from ledger (so any home isn't an option).
On top of that, you need to be listening at the exact time it exfiltrates data (it might intentionally wait for some time after using device), and you need to have the compromised device (which the hardest part here - you could test 100s of devices and not find anything).
So I think this could only be caught with a large scale, recurring lab testing, far from "trivial to detect".
It doesn't need to connect to or even turn on the eSIM until you already entered your key and code, by then it is too late. Unlike voice, it just needs a microsecond pulse to send the data. With all the wireless interference, you'd need a controlled setup too.