Heat Hacking Criminals Can Steal Your ATM PIN Code Via the Heat Your Fingers Leave Behind

The PIN digits you punch into an ATMs keypad to authenticate your transactions are leaving traces of themselves behind in the form of heat.

Someone following immediately behind an ATM user can use a digital infrared camera to determine what keys were pushed with about 80 percent accuracy...

Source:
http://www.popsci.com/technology/article/2011-08/heat-hacking-criminals-can-steal-your-atm-pin-code-heat-your-fingers-leave-behind