The point of these cameras is to deliver as many images of good quality as possible that show something of interest like a person, a car's numberplate and so on.

I almost guarantee you, if the camera even has a SIM-Card then it's pre-configured with all the necessary information to find and join the mobile core network via APN.

It turns on, joins the core network, gets handed an ip address and additional information like a servername/ip as its reporting endpoint, establishes the connection and starts taking pictures that it then sorts out and uploads.

That's pretty much it. No login credentials, no complicated protocols, nothing. The things is identified via IMEI, Mac or some other burned in "serial" and that's all that's necessary to make it happen.

So there are no credentials that could get lost, no technology that would be worth anything, access is being controlled on the network side and the images that are being taken are from a public place with no expectation for privacy.

The core system only has to be secure enough so that it doesn't get hacked via an open bluetooth tty or something and everything else is handled by the network it belongs to. That's why DNS manipulation and similar stuff doesn't get you anywhere.

Besides that, it has to be cheap and doesn't have to adhere to any security standards whatsoever. It's a pole with a mini camera and a solar cell that can just be vandalized by the next person that shows up.