Those Elevator Emergency Call Buttons Are Actually Pretty Janky

Those Elevator Emergency Call Buttons Are Actually Pretty Janky

We’ve all stared at that button in the elevator with the phone icon on it, supremely confident that if the cab came to a screeching halt while rocketing up to the 42nd floor, a simple button press would be your salvation. To be fair, that’s probably true. But the entire system is not nearly as robust as most people think.


Friday at DEF CON 27, [Will Caruana] took the stage to talk about phone phreaking on an elevator. The call buttons first appeared on elevators in 1968 as actual phone handsets, eventually becoming a mandated feature starting in 1976. Unfortunately, the technology they use hasn’t come all that far since. Phone modules on elevators did benefit when DTMF (touch tones) and voice menu systems rolled around. But for the most part, they are a plain old telephone service (POTS) frontend.


[Will] spends his spare time between floors pressing the call button and asking for the phone number. It’s the lowest bar of social engineering, by identifying yourself as an elevator service technician and asking for the number he is calling from. His experience has been that the person at the other end of the phone will give you that number no questions asked nearly every time. What can you do with a phone number? Turns out quite a bit.


The keys to the castle are literally in the elevator phone user manuals. The devices, shipped by multiple manufacturers, come with a default password and [Will’s] experience has been that nobody changes them. This means that once you have the phone number, you can dial in and use the default password to reprogram how the system works. This will not let yo ..

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