Automated Reverse Engineering using Lego®

State machine learning is a useful technique for automating reverse engineering. In essence, it involves fuzzing different sequences of inputs for a system. We show that this technique can be successfully used to reverse engineer hand-held smartcard readers for Internet banking, by using a Lego robot to operate these devices. In particular, the state machines that are automatically inferred by the robot reveal a security vulnerability in one such a device, the e.dentifier2, that was previously discovered by manual analysis, and confirm the absence of this flaw in an updated version of this device.