Continuing off from our last RFID Cloning with Proxmark3 post, we wanted to build a small, portable, stand-alone EM4x RFID tag stealer. We needed an easy way of storing multiple tag IDs whilst “rubbing elbows” with company personnel. The proxmark3 seemed liked an overkill and not particularly fast at reading em4x tags so we figured we’d try hooking up our RoboticsConnection RFID reader to a Teensy and see if we could make them play nicely together.
Our Proxmark 3 (and antennae) finally arrived, and we thought we’d take it for a spin. It’s a great little device for physical pentests, allowing us to capture, replay and clone certain RFID tags. We started off by reading the contents of the Proxmark wiki, to understand (more or less) what we are up against. This proved to be a vitally important step, and we are thankful we had the insight to RTFM a tad bit before.
In one of our recent engagements, we had the opportunity to test the physical security of an organization. This assessment presented an excellent scenario for a USB HID attack, where an attacker would stealthily sneak into a server room, and connect a malicious USB device to a server with logged on console, thus compromising it. From here, the “Peensy” (Penetration Testing Teensy?) was born.