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.
replyGood. You've got a read-only widget that monitors your freezer.
replyIf 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?
1) you'd wonder what broke
2) you'd wonder why it fixed itself
3) you'd check the ice cream when you got home
4) ice cream is fine, must have been a bug in the temperature reporting.
replyOff topic but "hack until the cows come home" put a smile on my face.
replyAir-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.
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replynot in this case where a thermosensor can do nothing but monitor a temperature.
replyYeah? 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?
replyRead-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.
replyThat makes it inconvenient to read, not impossible. E.g. use transmitted instead of reflected light (shine a bright light behind the paper) to see how much ink is in each place.
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