In OS X 10.8 it is possible to log in via SSH and get access to hardware input devices like microphone and iSight camera. Thus it is possible to remotely record audio and video of other users sitting in front of the machine. I consider this a severe security issue!
How to exploit this issue
Luckily, I didn't have to face a microphone exploit yet, but this question on Stack Overflow shows a little python script which enables you to capture pictures using the iSight camera from the command line. I don't think it is much harder to capture video.
One can disable the microphone using
sudo kextunload /System/Library/Extensions/AppleHDA.kext
…unfortunately this also disables all audio output.
The same applies for the iSight camera by unloading
IOUSB.kext, which most certainly might break all devices connected via USB, if not even causes a kernel panic.
How can I disable the microphone and iSight camera in an iMac (late-2012) under OS X 10.8.5 without breaking other system services?