While there are many ways for criminals to steal PINs for ATM access, one has not yet surfaced - thermal imaging.
Researchers tested the idea and found that it may be a viable alternative to placing hidden cameras or installing bugged ATM keypads. Covering their fingers during PIN entry won't hide the PIN. The residual heat left by ATM users could be used to make an educated guess of the users' PINs.
The researchers found that thermal imaging was more effective on plastic buttons versus metal buttons.
Crooks would have to account for how hard one presses a button and the need to find the right order of the numbers.
One easy way to prevent this method from working: touch random keypad buttons before and after entering your PIN.