What Are Cyber-Physical Systems, and How Do You Secure Them?

Cyber-physical systems (CPS) sense, compute, and act based on the data they collect. The computational technologies in CPS include data analytics, modeling, simulation, embedded processing, automation, and real-time decision making. As their value becomes clearer, these environments have become more widespread across various industries like healthcare, manufacturing, energy, transportation, and critical infrastructure. 

Unlike conventional IT networks, cyber-physical systems introduce additional considerations related to safety, uptime, device fragility, and operational continuity. However, as these systems become more connected, they also expand the organization’s potential attack surface and increase exposure. 

To secure cyber-physical systems, organizations need to know what they are, where they might be using them, and implement the technologies that help mitigate risks. 

What Are Cyber-Physical Systems?

Cyber-physical systems (CPS) integrate computing, networking, and physical processes. Embedded computers and software monitor and control physical processes, often creating feedback loops where physical processes impact computations that then drive changes to the physical processes. Unlike traditional embedded systems that operate in isolation, CPS are inherently networked, enabling them to interact with other systems and human users.

What Are the Key Features of a Cyber-Physical System?

A CPS system converges computing, communication, and control technologies with physical components so organizations can monitor, control, and optimize physical operations. To achieve these objectives, they have the following key features:

• Data-driven: Continuously collecting data using sensors embedded in the physical world for insight into the environment, system status, and operational parameters.
• Embedded Mobile Sensing and Data Fusion: Sensor networks integrated into mobile platforms or distributed across a location for collecting data from physical environments to overcome the limitations of individual sensors, reduce uncertainty, and gain a more reliable understanding of the physical world.
• Adaptable and Trainable Models: Artificial intelligence (AI) and machine learning algorithms learn from new data, adapt to changing conditions, and improve their performance over time to optimize systems operating in complex, unpredictable, and dynamic physical environments.
• Simulation-Based Design: CPS architectures and control algorithms can be modeled and tested in virtual environments, often using digital twins to replicate real-world behavior.

What Is the Difference Between Internet of Things (IoT) and Cyber-physical Systems?

While often discussed together, IoT and CPS are closely related. However, some ways that they differ include:

• Purpose and Scope: While IoT connects devices to collect and share data, CPS integrates computation with physical processes for real-time control.
• Connectivity: While IoT focuses on networked devices, CPS focuses on integrating computation with physical processes.
• Use Cases: While IoT devices include consumer products like wearables, CPS devices focus on industrial automation, autonomous vehicles, and robotics. 
• Data and Decision-Making: While IoT devices primarily gather data for analysis, CPS uses data to make real-time decisions and control systems. 
• Security: While IoT devices face privacy and network risks, CPS must address these issues as well as safety-critical vulnerabilities in physical operations.
• Complexity: While IoT systems are often simple and modular, CPS requires advanced algorithms, simulations, and precise coordination.
• Digital Twins: While IoT systems focus on data collection and sharing, CPS models and test physical processes in virtual environments using digital twins.

What Are Some Examples of Cyber-Physical Systems?

To improve security, organizations need to identify the cyber-physical systems in their operations. Some common CPS technologies include:

• Industrial Control Systems (ICS): Computer systems used to monitor and control industrial processes, like those found in power plants, water treatment facilities, manufacturing lines, and transportation networks.
• Operation Technology: Hardware and software that detects or causes a change to, monitors, or controls physical processes, like industrial control systems (ICS), supervisory control and data acquisition (SCADA) systems, and distributed control systems (DCS).
• Industrial Internet of Things (IIoT): Subset of IoT focused on connecting industrial machines, sensors, and devices to facilitate the collection and analysis of data within industrial settings.
• Building Management Systems (BMS): Systems designed to monitor and control mechanical and electrical equipment in buildings, such as HVAC, lighting, security, and fire alarm systems. 
• Smart Grids: Modernized electrical grids that incorporate digital communication technology to monitor energy flow, detect and respond to local changes in usage, and efficiently manage the distribution of electricity, often part of broader smart city infrastructures.
• Smart Buildings: Integration of various systems for building operations, energy efficiency, occupant comfort, and security, like orchestrating HVAC, lighting, access control, and environmental monitoring.
• Robotics and Distributed Robotics: Autonomous or semi-autonomous technologies that interact directly with the physical environment. 
• Smart Transportation Systems (STS): Technologies like intelligent traffic signals, autonomous vehicles, autonomous automotive systems, and vehicle-to-everything (V2X) communication that allow for real-time traffic management, collision avoidance, and route optimization.
• Smart Manufacturing: Digital technologies, automation, and data exchange are integrated into manufacturing processes to improve efficiency, flexibility, and quality. 
• Medical Devices: Connected health devices that collect patient data, analyze it, and perform actions to manage health conditions or assist in medical procedures for improved patient outcomes, including remote patient medical monitoring, automated drug delivery, and robotic surgery.

What Are The Challenges of Managing Cyber-Physical Systems?

As cyber-physical systems become more ubiquitous, organizations need to implement security measures that maintain availability and uptime while also mitigating data security risks. However, some key challenges that organizations face when trying to manage CPS security include:

• Operational Fragility: Active probing can cause instability, downtime, or safety risks, requiring passive discovery and device-aware security approaches.
• Limited Visibility: Distributed IoT and embedded devices often operate outside traditional IT asset inventories, creating blind spots that increase exposure and slow incident response.
• Legacy and Unpatchable Systems: Industrial control systems, medical devices, and building automation equipment may run outdated firmware that cannot be easily patched, increasing long-term vulnerability risk.
• Real-time Constraints: CPS environments depend on low-latency communication and continuous uptime, leaving minimal tolerance for security tools that undermine performance.
• IT/OT Convergence Complexity: IT and OT use different protocols, risk models, and safety requirements that security teams must manage using different tools. 
• Safety-Critical Risk Exposure: CPS vulnerabilities can lead to physical consequences that impact production lines, utilities, transportation systems, or patient care.

Best Practices for Managing Cyber-Physical Systems

Attempting to manage CPS manually easily becomes overwhelming for security teams. As organizations work to protect their systems, they should look for solutions that enable them to implement the following best practices. 

Prioritize Passive Asset Discovery

Active scanning tools that probe networks and equipment can take CPS offline. To create an accurate asset inventory, organizations should find solutions that:

• Uses passive network monitoring to identify IoT, OT, and embedded devices.
• Avoids disruptive active scanning in fragile production environments.
• Continuously discovers new and transient devices without manual effort.

Maintain a Continuous, Context-Rich Asset Inventory

In CPS environments, static lists become outdated quickly so organizations need a solution that continuously updates the asset inventory while augmenting it with necessary operational context. Organizations should look for a solution that: 

• Tracks device type, manufacturer, model, and firmware version.
• Correlates assets with known vulnerabilities and exposure status.
• Updates inventory dynamically as devices are added or reconfigured.

Prioritize Vulnerabilities Based on Risk

Without contextual prioritization capabilities, security teams have no way to identify the vulnerabilities that pose the greatest risks to safety and continuity. When evaluating a solution, organizations should consider whether it:

• Prioritizes vulnerabilities based on exploitability and real-world threat intelligence.
• Accounts for device criticality and operational impact.
• Supports mitigation strategies when patching is not immediately possible.

Supports IT/OT Network Segmentation

The convergence of IT and OT networks means that segmentation has become one of the most effective security controls to reduce lateral movement and rapidly contain threats. When looking for a solution to manage CPS, organizations should consider whether it:

• Identifies communication paths between IT and OT systems.
• Detects unnecessary east-west traffic.
• Provides insights to support micro-segmentation and access control policies.

Monitors Device Behavior and Network Anomalies

Since CPS devices directly influence physical processes, organizations should understand baseline behavior so that they can monitor for abnormal use or communications. When looking for a solution to help with this additional protection capability, organizations should consider whether it:

• Establishes behavioral baselines for connected devices.
• Flags abnormal traffic patterns or protocol misuse.
• Detects unauthorized configuration changes.

Accounts for Operational Constraints and Fragility

CPS environments require security controls that protect systems without introducing instability. To manage both security and operational resilience, organizations should find a solution specifically designed for a cyber-physical context. When looking for a solution to manage CPS, organizations should consider whether it:

• Minimizes performance overhead in real-time environments.
• Supports environments with legacy or unpatchable devices.
• Enables safe validation of changes through simulation or digital modeling.

Asimily: Passive Monitoring to Mitigate Cyber-Physical System Security Risks

With Asimily, security teams gain better insight into all assets connected to their systems. Our comprehensive, passive asset identification and classification capabilities provide visibility into every device category, enriched with the context necessary for actionable risk management. By consolidating discovery functions into a single, integrated platform, Asimily enables organizations to eliminate redundant tools, break down data silos, and accelerate incident response while safeguarding sensitive operational workflows.