Delegates at the recent DefCon conference may have been caught unawares by a malicious ATM kiosk.

According to a report by Wired, a malicious ATM kiosk was positioned in the conference centre of the Riviera Hotel Casino in Las Vegas. It captured data from an unknown number of delegates attending the DefCon conference before someone noticed something suspicious about the kiosk and an organiser for the conference said security authorities seized the device.

Witnesses say the kiosk was well placed to avoid surveillance cameras. Brian Markus, CEO of Aries Security who saw the machine, told Wired: “In any casino anything that is considered that high value has a camera, and they placed it where there were no [hotel] cameras visibly watching that exact spot where the ATM was.”

He claimed that it was clear to him that the ATM was fake when he looked at the smoked glass on the front of the machine and noticed something funny about it. When he beamed a flashlight through the glass, instead of seeing a camera behind it, he saw the PC that was set up to siphon card data.