On Thu, 2013-11-07 at 09:54 -0700, Nathan England wrote:

Is it possible to detect a keylogger built in the firmware of a 
keyboard? Do all keyboards have firmware? What if the keyboard does not 
have macros or extra keys or special keys (beyond blank keycaps)? Could 
the USB cable itself be a keylogger?

How would you go about detecting that?

Possible, unlikely, and for the most part undetectable. One of the strongest arguments for two-factor authentication. Then a key logger of any type isn't a compromised account.

Ted