Skimmers are malicious card readers attached to the real payment terminals so that they can steal data from every person that swipes their cards. The thief often has to come back to the compromised machine to pick up the file containing all the stolen data, but with that information in hand he can create cloned cards or just break into bank accounts to steal money. Skimmers often don’t prevent the ATM or credit card reader from functioning properly, making them harder to detect.
Even if the cards have a chip, the data will still be on the card’s magnetic strip to be backwards compatible with systems that can’t handle the chip, he told us. Some merchants still require customers to use the magstripe.
An ATM skimmer is a small device that fits over an existing card reader. A camera may be in the card reader, mounted at the top of the ATM, or even in the ceiling. Some criminals install a fake PIN pads over the actual keyboards to capture the PIN directly, bypassing the need for a camera.
Instead of skimmers, which sit on top of the magstripe readers, shimmers (harder to spot) are inside the card readers. These are very, very thin devices and cannot be seen from the outside. When you slide your card in, the shimmer reads the data from the chip on your card, much the same way a skimmer reads the data on your card’s magstripe.
check for some obvious signs of tampering at the top of the ATM, near the speakers, the side of the screen, the card reader itself, and the keyboard. If something looks different, such as a different color or material, graphics that aren’t aligned correctly, or anything else that doesn’t look right, don’t use that ATM. The same is true for credit card readers at the checkout line or at gas stations.
Whenever possible, don’t use your card’s magstripe to perform the transaction. For credit card readers in stores, feel underneath the PIN pad for a slot to insert your card and its EMV chip to be read.