ICS Study Guide 2026

Modbus is one of the oldest and most widely used serial communication protocols in SCADA (Supervisory Control and Data Acquisition) systems and other industrial control applications. It allows devices like PLCs, RTUs, and sensors to communicate with each other and with supervisory systems. Despite its age, Modbus remains prevalent due to its simplicity and widespread adoption, though it lacks inherent security features.

Regular security training reduces human error, the most common cause of security breaches, by keeping all staff aware of current threats and proper procedures.

Staying current ensures professionals provide the best possible service by incorporating the latest knowledge, techniques, and regulatory requirements.

The principle of least privilege limits access to the minimum necessary for job functions, reducing the attack surface and potential impact of compromised accounts.

Many legacy ICS protocols, such as older versions of Modbus or DNP3, were designed in an era when security was not a primary concern and systems were often air-gapped. Consequently, they commonly lack modern security features like authentication, encryption, or integrity checks. This inherent vulnerability makes them susceptible to various attacks, including eavesdropping, tampering, and unauthorized control, without built-in protections.

Aligning with standards helps improve security posture, meet compliance obligations, and reduce the risk of cyber threats.