Building Management System Cybersecurity Best Practices

Building Management System Cybersecurity

A strong cybersecurity posture is essential for Building Management Systems to mitigate the risks associated with interconnected devices and systems.

Building Management System Overview

A Building Management System (BMS), also known as a Building Automation System (BAS) or Building Control System (BCS), is a computer-based control system that manages and monitors the mechanical, electrical, and plumbing systems in a building. These connected components include heating, ventilation, and air conditioning (HVAC) systems, lighting, access control, elevators, life safety, and more. BMS systems are used to control and optimize building operations, enhance occupant comfort, and improve energy efficiency.

Building management systems and related analytics services are used to manage occupant comfort, optimize energy use, reduce operational costs, and create a more sustainable built environment.

Key components of a Building Management System include:

  • Sensors and Actuators: Monitor environmental conditions such as temperature, humidity, and lighting, and control systems such as HVAC (Heating, Ventilation, and Air Conditioning) and lighting.
  • Controllers: Process data from sensors and actuators and make decisions based on predefined logic and algorithms to control building systems.
  • User Interface: Enables building operators to monitor system performance, adjust setpoints, and view alarms and alerts.
  • Communication Network: BMS systems use communication protocols such as BACnet, Modbus, and LonWorks to connect sensors, controllers, and other devices in the system.
  • Energy Management: BMS systems can optimize energy usage by monitoring energy consumption, identifying inefficiencies, and implementing energy-saving strategies such as demand-controlled ventilation, motion or occupancy-based lighting, and daylighting.
  • Security and Access Control: BMS systems can integrate with security systems to control access to buildings and monitor security cameras and alarms.
  • Maintenance and Diagnostics: BMS systems can generate reports on system performance, diagnose issues, and schedule maintenance tasks to ensure optimal operation.

Building Management System Cybersecurity Challenges ad Vulnerabilities

The basic communication protocols (e.g. BACnet, Modbus, LONworks) used for building management systems and building controls are inherently unsecure. As the capabilities of connected buildings expand, so do the challenges of securing them. Since modern building management systems rely on a network of devices communicating with each other, and connectivity to cloud-based services through the Internet, vulnerabilities can be exploited by malicious actors. Common risks include unauthorized access to building systems, manipulation of environmental controls, and potential breaches of sensitive data collected by sensors. The shift towards remote access and cloud-based solutions further amplifies the attack surface, necessitating robust security measures to protect against cyber threats.

Building Management System cybersecurity is not just a feature but a fundamental requirement to protect critical infrastructure, operations, and occupants.

Best Practices for Building Management System Cybersecurity

  1. Network Segmentation: Keep the IT and building management system network separate, and also divide the BMS network into isolated segments to limit lateral movement in case of a security breach. This reduces the impact of a potential compromise and enhances overall network security.
  2. Authentication: Implement robust identity verification mechanisms for users, devices, and data. Multi-factor authentication, biometric authentication, and strict access controls based on roles are integral to the Zero Trust approach.
  3. Continuous Monitoring: Deploy real-time monitoring systems to detect anomalies and potential security incidents. Automated alerts and responses ensure that any deviation from normal behavior is addressed promptly.
  4. Encryption: Secure data in transit and at rest through the use of strong encryption protocols. This safeguards sensitive information exchanged between devices and systems within the smart building ecosystem.
  5. System Updates:Maintain up-to-date software and hardware to ensure that building systems are running on the latest, most secure versions.
  6. Incident Response Planning: Develop comprehensive incident response plans tailored to the unique challenges of building management systems. These plans should outline clear procedures for addressing security incidents, minimizing the potential impact on building operations.
  7. User Education and Awareness: Foster a culture of cybersecurity awareness among building occupants and personnel. Educate users about potential risks, the importance of adhering to security protocols, and their role in maintaining a secure Smart Building environment.
  8. Contractor Performance: Require system integrators and contractors to implement you cybersecurity procedures when accessing your building management system for monitoring, modifications or additions.
  9. Regular Security Audits and Assessments: Conduct regular security audits and assessments to identify vulnerabilities and areas for improvement. Regular testing ensures that security measures remain effective against evolving cyber threats.

Building Management System cybersecurity is about about safeguarding the physical environment, ensuring operational continuity, and protecting data.

Zero Trust for Building Management System Cybersecurity

The National Institute of Standards and Technology (NIST) Zero Trust architecture has gained prominence as a robust approach to cybersecurity. Originally applied to IT networks, NIST Zero Trust principles are increasingly relevant for smart building cybersecurity and securing building controls. The fundamental tenet of Zero Trust is the elimination of implicit trust in any entity, whether inside or outside the network. Every user and device, even those within the network perimeter, must be continuously verified before being granted access to a resource.

Applying Zero Trust to building management systems controls involves rethinking traditional security models. Instead of relying on a presumed secure internal network, access controls are implemented based on the principle of least privilege. Users and devices are only granted access to the specific resources necessary for their roles, reducing the risk of lateral movement in case of a security breach. For the device-to-device communication in building networks, this means that each device must be authenticated in order to communicate with another device.

Continuous monitoring is a cornerstone of Zero Trust. In the context of Smart Buildings, this means real-time scrutiny of devices, sensors, and users. Any unauthenticated communication attempts will be blocked in real-time and will trigger an alert. The security of the building controls is not compromised while waiting for an investigation to begin. This is a proactive approach to security embodied in DOME that aligns with the real-time operations of Smart Buildings.

Zero trust is not just a proactive security model for building management systems, it is the future of cybersecurity and requires a mindset shift that requires continuous verification and validation of every device, user, and application accessing the network, that aligns with the dynamic nature of modern digital infrastructure.


As building management systems become more capable, pervasive, and expansive, securing all device of these systems becomes paramount. Embracing the NIST Zero Trust framework for building controls provides a comprehensive and adaptive approach to cybersecurity. By implementing best practices, continuous monitoring, and user education, facility managers can navigate the complexities of securing building management systems.

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Keywords: Building Management System Cybersecurity