alt Hacker NewsThat’s a tough question. If your PLC is on an airgapped LAN, admin/admin is not great security hygiene but you’ve reduced most of the risk by airgapping.
On my project the service I wrote was doing bidirectional communication with the PLC over OPCUA. The server running this pod was connected to the internet, so it was critical to have proper TLS for the OPCUA client/server. Rotating LetsEncrypt certs on the system every 45 days is a lot of toil, but using a self-signed cert that expires in 2040 from some dev laptop doesn’t pass muster in most organizations either.
That’s just the OPCUA path.. In these projects You also typically see WinCC HMIs that can talk to the PLC from anywhere on the network without TLS. And also SIMATIC Web Server pages - minimally secured by default, and the amount of info you can grok about the system in Chrome Dev Tools is troubling.
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Just my opinion but I believe a self-signed is more secure than Let’s encrypt. When a self-signed cert changes and no one in the org knows why that is alarming. Getting certificate error messages every month and half every numbs the org to the alarm.
I'm not sure if you're speaking from personal experience, but most I've interacted with don't have to worry about the self-signed vs. LetsEncrypt debate. They just don't do it. Also there would be no way to do LetsEncrypt as the system is air gapped.
> Rotating LetsEncrypt certs on the system every 45 days is a lot of toil
What is unique about your system using LetsEncrypt that you can't automate certbot to handle this task as it was designed and intended to be done?
> admin/admin is not great security hygiene but you’ve reduced most of the risk by airgapping.
admin/admin is on a post-it stuck to the monitor because everyone we hire is perfectly capable of rooting a machine they have physical access to.