Almost a year ago, I wrote about ATM skimmers made of parts from old MP3 players. Since then, I’ve noticed quite a few more ads for these MP3-powered skimmers in the criminal underground, perhaps because audio skimmers allow fraudsters to sell lucrative service contracts along with their theft devices.
Using audio to capture credit and debit card data is not a new technique, but it is becoming vogue: Square, an increasingly popular credit card reader built for the iPhone, works by plugging into the headphone jack on the iPhone and converting credit card data stored on the card into audio files.
The device pictured here is a card skimmer designed to fit over the card acceptance slot on a Diebold Opteva 760, one of the most common ATMs around. The green circuit board on the left was taken from an MP3 player (no idea which make or model). When a card is slid past the magnetic reader (the small black rectangle at the end of the black and red wires near the center of the picture), the MP3 player “hears” the data stored on the card’s magnetic stripe, and records it as an audio file to a tiny embedded flash memory device.