Security risks in MQTT-based Industrial IoT Applications

Internet of Things (IoT) plays a crucial role in improving the quality of life. In recent years, IoT systems have proliferated in almost every industry, including manufacturing, automobiles, agriculture, and energy. IoT is the key enabling technology for Industry 4.0. This growing reliance on IoT devices piqued the interest of several adversaries attempting to gain unauthorized access to IoT systems for illicit purposes. So, it is essential to identify any potential security risks in IoT systems. Numerous Industrial Internet of Things (IIoT) applications, including wind turbines, agriculture, and warehouses, deploy hundreds of IoT devices in remote locations. These IoT devices are not physically monitored since it requires extensive human effort. Instead, the IoT devices are monitored by web applications that collect sensor data from remote devices. IoT application-layer protocols are responsible for communication between web applications and IoT devices in such large-scale IoT systems. Any communication flaw could put the entire IoT system at risk. The publish/subscribe-based MQTT protocol is a widely used IoT messaging standard. In this paper, we present a threat model and demonstrate a specific weakness in unencrypted MQTT-based IoT systems that enables an attacker to gain unauthorized access to the entire system by launching a combination of man-in-the-middle (MITM) and cross-site scripting (XSS) attacks. We also discuss steps to be taken and future directions for research in the security of industrial IoT systems using the MQTT communication protocol to avoid the possibility of such attacks.