Researchers show ATM theft by thermal imaging

The research team from the University of California, San Diego, found that their cameras picked up a PIN entered on a keypad more than 80 percent of the time if used immediately. If used a minute later, it picked up the digits about half the time. After 90 seconds, the chance of extracting the digits dropped to about 20 percent. They tested the frequency using custom software that they wrote to automate their analysis.

Not sure how big of a threat this would be for someone who walks up to a machine. I haven’t had to use an ATM is a while, but in the transactions I’ve done it seems that there is a reasonable (from a security standpoint) delay between PIN entry and finishing your transaction. I expect the threat would be from a camera mounted along with a skimmer.