Comment by stymaar
9 hours ago
If what's needed is the ability to monitor them, then why are these things remote-controllable?!
Obviously read-only access to some sensor is not the same attack surface as having the ability to remotely shut-down the refrigeration.
Same reason website's are remote controllable. There's someone who's job it is, is to make sure the fridge is up and running, 24/7 and for the same reason that website operators/SREs don't live at each POP/DC, that fridge operator wants to remotely be able to flip some relays off and on to fix the problem without having to drive onsite, if possible. Additional, a single person/fewer people can then also be responsible for multiple/more sites.
That’s exactly right. There all all sorts of read-only architectures where the device can be monitored without every directly accessing it:
- The device’s control has a radio transmitter that emits its readings, but no receiver. Listen for those messages to monitor it but there’s not a physical path to reply to it.
- The device’s controller writes a database or message queue. Its code never reads from that source. Monitors listen to those messages.
And many, many similar methods with the same core concept: the item transmits its status but doesn’t have a method to receive replies. You just have to commit to using any one of those thousands of mechanisms.
The fridges are cheaper to make because they don't need a bunch of knobs and switches and temperature displays - just an app on employee phones.
How is a button more expensive than a computer with network access?
Because then you can charge for the network access!
Read-only access is mostly an illusion that itself can be hacked to gain control.
I have a read only temperature sensor in my old-school non-computerized refrigerator and freezer. Hack until the cows come home but it still can't turn off my freezer.
Good. You've got a read-only widget that monitors your freezer.
If it were hacked to start delivering temperature readings that were dangerously-high while you were out of town, then: Would you keep the food, or discard it?
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Off topic but "hack until the cows come home" put a smile on my face.
Air-gapping, network segregation, data diodes, etc. are all real things. It's possible to make a read-only refrigerator that is "unhackable". I have a temperature monitor in my refrigerator right now. Hack that monitor and it doesn't affect my refrigerator at all.
not in this case where a thermosensor can do nothing but monitor a temperature.
Yeah? We had an old Unix server that printed its logs in realtime to a dot matrix printer. How are you going to gain control of that?
Read-only is a strong control with lots of solid implementations.
Depending on the make and model, send a reverse feed code and then overwrite with block characters. You will know that something bad happened, but you won't know what.
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because you might not want to send a technician to every single one of them once a firmware update is needed