You just made me think of what might actually be be possible if you could hack a microwave through the control pad. I'm not sure what could be accomplished with sending unrestricted commands to the hardware in a microwave, but depending on the cheapness of the components, I suspect it's not good.

I have a friend who succeeded in emulating a microwave using MAME and a dump of the microwave's ROM. (I don't remember exactly what all of the microcontroller outputs are; most of them have to do with the LED user interface rather than activating the magnetron.) Of course the emulated microwave can't really cook food (maybe only emulated food...), but you could use that kind of emulation with a debugger to experiment with possible software vulnerabilities.

Since it was possible to reprogram Super Mario World through the controller, it seems pretty plausible that it's possible to reprogram some embedded systems through their UI even when they're not designed for that!

http://hackaday.com/2015/01/22/reprogramming-super-mario-wor...

> Since it was possible to reprogram Super Mario World through the controller, it seems pretty plausible that it's possible to reprogram some embedded systems through their UI even when they're not designed for that!

That's about what I was thinking. Hell, if there's a standard set of firmware that most, or even just most cheap ones ship with, then it might even work for a large chunk of the units in the wild.

I think an entertaining short story could be premised on this idea.