It is an issue, dial up lacks tunnel encryption and if you managed to make it, it will be useless in real scenarios, and 3g is being phased out and obsolete

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fc417fc802 5 hours ago | parent [-]

Secure the contents of the tunnel and it doesn't matter. Provide a secure backbone and it doesn't matter. Realize that dialup is so slow that you can transparently tunnel it across ~any modern network (for which you can encrypt the tunnel) and it doesn't matter.

Tunnel your dialup within your obsolete 3g network, and then tunnel that obsolete 3g network within something modern. The obsolete technologies are not the issue here.

Also the thing about dialup is that it's point to point so the attack surface isn't even remotely comparable to exposing a port on the open internet. I should generally be able to trust the link that my phone company provides. Faxes are still used in many secure settings in preference to email.

	▲	tamimio 5 hours ago \| parent [-]
		For 3G, it’s phased out, so the bands will be gone, you have to upgrade it. The dial up part is far more involved, especially when they have auto answering connected directly to PLC or HMI, mostly with shared passwords. Also, you can’t trust the network operator either, insider threats and rogue employees are a threat. Additionally, dial ups are less monitored compared to modern network, and usually you end up with duct tape solutions like jump server to have strong authentication and continuous logging in firewall and such, plus proper encrypted tunnels so even physical wiretapping isn’t possible, and the assumption of air gap isn’t there because it’s reachable through public telephone, and the worst part, these dial ups are usually connected to windows XP Scada developers machines. To add, obsolete is bad too, when your device cease to have vulnerability patches, you are screwed regardless of whatever configs you put.