I am wondering whether there is a way to defend against USB Keyboard Keylogger (obviously other than physically checking the keyboard every time after leaving my computer unattended).
These days, people can buy cheep hw keyloggers, such as the Keyllama USB Keylogger, which are small and quite hard to discover unless you are looking for it.
If somebody wanted to install such keylogger on my computer, he would have to disconnect the keyboard first. Provided the machine is running (I always leave my machine running), this event would be logged in
/var/log/kernel.log. So that might be one way to alert me.
Is there some other way?
EDIT: I should add, that my whole hard disk is encrypted, and thus an attacker cannot just boot from USB/CD and modify my system. He might format my disk/destroy my machine, but that is not the issue here.
Also, when I leave my office, I leave my machine running, but I always log out.
In my office, power outages are extremely rare. If one happens, this will be a reason for me to thoroughly check my machine for any possible intrusion.