Vulnerability Analysis and Security Schemes for MAVLink-based Unmanned Aerial Vehicles

Abstract

In recent years, Unmanned Aerial Vehicles (UAVs) have been utilized in a variety of fields such as military, emergency assistance, agriculture, commercial and personal hobby. However, the explosive growth in popularity of UAVs also incurs more possible malicious attacks. Therefore, it is necessary to analyze the vulnerability of the UAV control system. And also, measures should be taken to secure the communication between UAVs and authorized controllers. In this paper, we focus on the Micro Air Vehicle Link (MAVLink) protocol, a very lightweight communication protocol for Unmanned Aerial Vehicles (UAVs) and Ground Control Station (GCS). Firstly, we study and analyze the vulnerability of MAVLink protocol. We find that in order to guarantee transmission speed and keep the protocol simple, all the MAVLink packets are sent in plain text, which makes it easy to attack a UAV. We exploit this vulnerability and put forward an attack method to hijack and make malicious use of a UAV. Then, we carry out attack experiments on a virtual UAV running on the simulator. The experiment results confirm that our proposed attack methodology can be actually used to illegally control a UAV like changing the speed or repositioning the UAV. We further propose a countermeasure to defend against attacks on UAVs utilizing the vulnerability of MAVLink protocol. We make a flexible use of one field of the MAVLink message to check the legality of received packets. The countermeasure test results demonstrate that by extending the function of an existing field of MAVLink messages, our proposed countermeasure can be used to prevent the UAV from executing malicious MAVLink command injected by an attacker.