| Industrial control systems are responsible for operating national infrastructure such as electrical grids, oil pipelines, water systems, and several others. They have historically run on their own protocols and networks, isolating them from traditional networks. The core functionality of these networks requires constant availability, reliability, and maintainability. Modbus is a industrial control network protocol developed for serial connections. However, as TCP/IP has become ubiquitous, industrial control systems are being connected to traditional IT networks. TCP/IP functionality has been added to Modbus and all of the advantages and disadvantages of TCP/IP are now present in industrial control networks. Before using TCP/IP, industrial control networks were isolated systems that did not need to address security.; A new set of security tools are required to protect the nation's critical infrastructure. This dissertation proposes an architecture and implementation of a distributed network scanner for Modbus industrial control networks. The scanner will be able to passively and actively scan a Modbus network to discover all connected devices. Additionally, the scanner will be distributable and scalable to handle the large sizes industrial control networks can achieve. The scanner will improve the management and security of industrial control systems where it is deployed. |
