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Repeat after me: safety is not security. Ponder this for a while. Safety is about giving guarantees that the right response happens at the right time to prevent
by gmueckl 8y ago
Repeat after me: safety is not security. Ponder this for a while. Safety is about giving guarantees that the right response happens at the right time to prevent disaster. Security is making sure that whoever you are communicating with is who they claim to be and not an imposter.
Heavy industry cares a lot for safety. An exploding refinery is not in any company's best interest. But the systems they rely on have absolutely no notion of security. They have no way to distinguishing between true and spoofed input values that are fed into a control system.
- mikeash 8y agoBy those definitions, a refinery whose control systems ensure it can never explode, but allow anyone with internet access to override anything, is insecure but perfectly safe. Yet the result is explosions and dead people. That doesn't make sense.
- gmueckl 8y agoNo, it does make perfect sense in a way. Safety in these terms means that things are extremely unlikely to go wrong by themselves. Interventions are simply not a part of that model. There is some, but not a lot of awareness in the industry that the implicit trust between components in these systems is insecure and ultimately jeopardizes their safety. It is too easy to spoof process values that are sane, but do not reflect the true state of the system. The systems fundamentally miss any mutual authentication between their components. Process measurement devices typically even offer a simulation mode in their firmware to do just that. At worst, all you have to do is to crack a simple password to gain access to this feature remotely.