PHDays (Positive Hack Days) is a yearly forum with a focus on ethical hacking and security. During this years forum which took place in June, the organizers set up a competition where the goal was to “steal” or take control of a Syma X8C quadcopter drone. The drone runs on the nRF24L01 module, which from previous posts we have seen can easily be sniffed and decoded with an RTL-SDR or other SDR.
To reverse engineer the drones wireless communications system the teams used software defined radios like the HackRF and BladeRF, and also an alternative method involving just using an Arduino and nRF24L01+ receiver chip. Once the signal was received, they used GNU Radio to decode the signal into packets of data. After analyzing the data they found that the data bytes were easily reverse engineered and then were able to transmit their own data packets to control the drone. The post goes into further detail on the specifics of the reverse engineering.