Crooks in the US are targeting Ingenico card readers at shop self-checkout lanes, placing overlay skimming devices on the machines to steal data and PINs.
Security blogger Brian Krebs has shared images of the skimmers, which look identical to the Ingenico card readers' surfaces, fitting snuggly over them.
The skimmers nab data when cards are swiped and PINs that are typed in before using Bluetooth to send it to other devices that are within a few metres.
Krebs was sent the images by a source at an unnamed retailer who says that the skimmers seem to have been built using parts taken from Samsung phones and that they do not have internal storage, meaning that a second wireless device would be needed to obtain the card data.