Industrial Control Systems (ICS) have evolved over the years and now have a lot in common with traditional IT systems. Low-cost Ethernet and IP devices are replacing older, proprietary technology, which opens up new possibilities to improve connectivity and remote access. However, it also increases vulnerability to cyberattacks and incidents since the system is no longer segregated. Due to the nature of ICS, they differ from other IT systems. A compromised system can cause severe damage to the environment, incur substantial financial and production losses, and negatively impact an entire nation.

Modbus is a simple and flexible protocol used by a wide variety of industrial and automation equipment. Its simplicity has made it attractive for many manufacturers, but it also poses a number of challenges in terms of security and traffic analysis. In this post, we’ll show you how to use NXLog to capture, process, and extract useful security information from Modbus traffic. What makes Modbus traffic analysis challenging? Modbus is a low-level protocol that effectively uses only two data types: bits (in the form of coils), and 16-bit words (in the form of registers), which are also the only form of data that can be natively addressed with most devices.