Exploring Diverse Methods of Reverse Engineering MQTT Client Interfaces

Abstract

The fast evolution of Industry 4.0 and smart manufacturing has led to an increased reliance on MQTT (Message Queuing Telemetry Transport) as a lightweight messaging protocol for efficient machine-to-machine communication. Despite MQTT being well-suited as a standard protocol for the Industrial Internet of Things and the increasing provision of MQTT interfaces by manufacturers for their production machines, the presence of poorly documented, non-machine-readable APIs poses challenges. Consequently, integrating these devices into an existing production environment requires significant effort and is prone to errors.In this paper, we explore diverse methods for extracting valuable information from running MQTT clients, enabling the reconstruction of their communication interfaces with the associated endpoints. This information can then be transformed into a standardized machine-readable format. The AsyncAPI Initiative has defined such an industry standard for defining asynchronous APIs, which includes MQTT. These AsyncAPI Specifications can be used to make a subsequent implementation of programs that interact with these interfaces more fast and reliable.The presented approaches focus on extracting interface information by analyzing network traffic and MQTT messages. We concentrate on observing the behavior of MQTT clients from an external perspective, deliberately disregarding the internal workings and program code of the clients themselves. Furthermore, we discuss an approach to map the data from the intercepted MQTT communication to a AsyncAPI Specification.Through our research, we aim to provide insights into the various techniques that can be employed to reverse engineer MQTT client interfaces effectively. By leveraging these approaches, it is possible to gain valuable knowledge about MQTT client communication interfaces, thus simplifying the subsequent implementation of programs that interact with these interfaces.