7 Steps to Strengthen Building Automation Cybersecurity

Building Automation Cybersecurity has become a critical priority as modern buildings increasingly rely on connected controls for HVAC, lighting, security, and other systems. Cyber attacks on these building automation systems (often called BAS or BMS) can disrupt operations or even endanger occupants. All types of facilities – commercial offices, industrial plants, residential high-rises, and mixed-use complexes – face similar risks as they adopt “smart building” technologies. This article presents seven key steps to strengthen the cybersecurity of building automation systems. The tone is technical and objective, providing clear guidance suitable for an internal training manual or documentation. Each step includes practical measures and real-world considerations, drawing on established cybersecurity standards (like ISO 27001, IEC 62443, and NIS2) without any promotional bias.

7 Steps to Strengthen Building Automation Cybersecurity

Here are 7 Steps to Strengthen Building Automation Cybersecurity you must learn in 2025:

Step 1: Assess Risks and Inventory All Systems

The first step in building automation cybersecurity is to identify what you have and evaluate the risks. You can’t protect what you don’t know exists. Conduct a thorough audit of all building automation components, including HVAC controllers, lighting controls, elevators, access control panels, surveillance systems, and any IoT sensors integrated into the building. For each asset, document details such as device type, software/firmware versions, network interfaces, and the functions they control. This inventory provides the foundation for assessing vulnerabilities and potential impact.

Perform a cybersecurity risk assessment focusing on the building systems. Consider questions like: What could happen if this boiler controller is hacked? Could an attacker manipulate environmental controls, disable alarms, or jump from the building network into corporate IT systems? Evaluate both the likelihood of threats (e.g. malware infection, unauthorized access) and the impact (e.g. equipment damage, safety hazards, financial loss). Prioritize risks using a structured method (aligning with frameworks such as ISO 27001’s risk management process). For example, an internet-exposed building management server with outdated software would rank as a high risk, whereas a standalone lighting controller with no outside connectivity might be lower.

Key Actions:

• Compile a detailed inventory of all building automation system (BAS) devices, software, and network connections.

• Identify vulnerabilities and threats for each component (e.g. outdated firmware, default passwords, open network ports).

• Assess the potential impact of each risk on operations and occupant safety, and prioritize remediation of high-risk items.

• Use standards-based methodologies for risk assessment (for instance, following ISO 27001 guidelines or IEC 62443-3-2 for industrial risk assessment) to ensure a comprehensive evaluation.

Step 2: Implement Strong Access Controls and Credentials

Controlling access is fundamental to cybersecurity. Implement strict user access management for all building automation systems. Many breaches occur due to weak or default credentials. Start by eliminating default usernames and passwords on BAS devices and software interfaces – those should be changed upon installation. Enforce a strong password policy (complex passwords that are unique for each account) and avoid shared accounts. For example, each building engineer or facility manager should have an individual login, rather than everyone using a generic “admin” account. This prevents a compromised password from granting broad access.

Use role-based access control to limit each user’s permissions to only what they need to do their job (principle of least privilege). A contractor responsible for HVAC maintenance should not have the ability to disable the security alarm system, for instance. Wherever possible, enable multi-factor authentication (MFA) for remote or high-privilege logins – this adds an extra layer beyond just a password. Many modern building management platforms now support MFA or integration with corporate single sign-on systems.

Don’t forget physical access security as part of access control. Secure the rooms or closets where control system hardware resides (controllers, network switches, servers). Only authorized personnel should be able to enter these areas, as an intruder could otherwise plug in a rogue device or directly connect a laptop to the control network. Key cards, locks, and surveillance for these critical areas are important. Additionally, manage and monitor any third-party access: if vendors or integrators need to log in for maintenance, ensure they use secure methods and that their accounts are disabled when not in use.

Key Actions:

• Remove or change all default passwords on BAS devices and applications immediately upon deployment.

• Create unique user accounts with strong passwords; avoid sharing credentials among staff.

• Apply role-based permissions so that each user can only access systems and functions relevant to their role.

• Enable multi-factor authentication for remote access or administrative accounts to prevent unauthorized logins.

• Secure physical equipment locations (control panels, server rooms) against unauthorized entry and supervise any third-party or vendor access to the systems.

Suggested article to read: Cybersecurity in Construction; Guide to 2024

Step 3: Segment Networks and Secure the Connections

Network segmentation is a powerful strategy to contain threats and minimize unauthorized access to building systems. In practice, this means isolating the building automation network from other networks. Building control devices and supervisory servers should operate on dedicated VLANs or physically separate networks, distinct from the corporate IT network or public internet. By creating this separation, even if an attacker compromises a device on the building network, they cannot easily move laterally into office computers or data centers (and vice versa).

Implement firewall rules and gateways between the building automation system (BAS) network and any other network. Only allow the minimum required data flows. For example, if the BAS needs to send data to a cloud monitoring service, permit just that specific outbound connection and block all other inbound traffic. Many building systems use specific protocols (BACnet, Modbus, KNX, etc.); ensure your network controls (firewalls or routers) whitelist only the necessary protocols and IP ranges. Whitelisting known good communication and blocking everything else is more secure than broadly trusting an internal network.

Limit any direct internet access for building devices. Ideally, the BAS network should not be reachable from the internet at all. If remote access is needed for facility managers or vendors, use secure methods like a VPN (Virtual Private Network) or remote desktop gateway that authenticates users strongly and encrypts the connection. Avoid opening common ports (HTTP, Telnet, RDP, etc.) directly on control equipment. In one real-world case, attackers breached a retailer’s network via an HVAC control contractor’s remote connection – underscoring why direct links to building systems must be locked down.

Key Actions:

• Isolate building automation systems on a separate network segment or VLAN, away from business IT networks and public internet.

• Use firewalls or secure routers to strictly limit traffic between the BAS network and other networks, only permitting necessary protocols/ports.

• Avoid exposing BAS devices to the internet; require remote users to connect through secure VPNs or jump-hosts with proper authentication.

• Implement IP address and port whitelisting: only allow known, authorized devices and services to communicate with the building systems.

• If applicable, apply the IEC 62443 “zones and conduits” concept to design network architecture – group systems into security zones and tightly control data conduits between them.

Step 4: Harden System Configurations and Manage Vulnerabilities

Secure configuration (or “hardening”) of building automation components is essential to remove easy exploitation paths. Upon installation or during commissioning of a building system, configure every device and software service with security in mind. This involves disabling or uninstalling any features that are not used. For example, if a controller has an open FTP or Telnet service that isn’t needed, turn it off to reduce the attack surface. Ensure default accounts are removed or secured (as addressed in Step 2). Many BAS come with vendor documentation on security hardening – follow these guidelines to enable built-in security settings such as encryption, account lockouts, or network filtering on the devices.

Where possible, use encrypted protocols for communication between building devices and their management workstation. If your system supports a secure version of BACnet (like BACnet/SC which uses TLS encryption) or secure SNMP, implement it so that sensitive data isn’t sent in the clear. Also, protect data at rest – if the building management system stores historical data or configuration backups, that server should have disk encryption and proper access control.

A crucial part of vulnerability management is applying software updates and patches. Outdated software and firmware often contain known vulnerabilities that attackers can exploit. Establish a routine to check for updates from vendors of your BAS, PLCs, cameras, and other connected equipment. When updates are available, test them in a non-production environment if possible (for example, on a spare controller or a simulation of the BAS) to ensure compatibility. Then apply the patches during a maintenance window. Regular patching keeps you ahead of known exploits – many breaches, especially in industrial control settings, occur on systems that hadn’t applied available fixes.

Because building systems may have long lifecycles, also plan for how to handle components that no longer receive updates. If a vendor has ceased support (end-of-life) for a controller, you may need to segment it more strictly or plan for its replacement to maintain security. Additionally, implement anti-malware measures on any Windows or Linux servers in the BAS (like the front-end workstation or database server). Use application whitelisting where feasible to allow only approved programs to run. These measures align with industry recommendations (for instance, application whitelisting and prompt patching are top strategies in industrial cybersecurity guidelines from organizations like CISA and ISA).

Key Actions:

• Follow vendor hardening guides: disable unused services and ports, remove default accounts, and enable security features on all BAS devices.

• Ensure communications within the building automation network use secure protocols (VPN, TLS encryption, secure versions of industrial protocols) when supported.

• Keep all building automation software and device firmware up to date by applying security patches regularly on a defined schedule.

• Test updates in a controlled environment before deployment to avoid compatibility issues in critical building operations.

• Download patches only from reputable, verified sources and verify their integrity (to prevent fake or malicious updates).

• Develop a plan for legacy systems that no longer receive updates (additional isolation or phased replacement) to address their vulnerabilities.

Step 5: Monitor Activity and Detect Threats Continuously

Even with preventive measures in place, you must assume that some threats might slip through. Continuous monitoring of your building automation environment helps you detect suspicious behavior early and respond before major damage occurs. Start by enabling system logs and audit trails on all BAS platforms. Configure the building management software to record events such as user logins (successful and failed), configuration changes, alarm acknowledgments, and network connections. These logs are invaluable for forensic analysis and can also provide real-time indicators of an attack (for example, repeated login failures on an admin account or an unexpected change in a controller’s program).

Implement network monitoring on the BAS segment. This can range from simple traffic monitoring (observing if there’s a surge in data or contact with unknown external IPs) to deploying specialized intrusion detection systems (IDS) for industrial networks. There are ICS-specific IDS tools that can baseline normal building control traffic and alert on anomalies, such as a new device appearing on the network or a command issued outside of normal parameters. For instance, if a lighting controller suddenly starts communicating with an external server in another country, that would be a red flag to investigate.

Integrate the building systems monitoring with your broader security operations if possible. Many organizations feed BAS logs into a central Security Information and Event Management (SIEM) system alongside IT logs. This unified view can correlate events (e.g., an employee’s IT account was compromised and then used to attempt access to the BAS). If a dedicated cybersecurity team exists, ensure they are aware of the building systems and have visibility into those networks. In smaller organizations, at minimum, designate someone to review the building system security logs on a regular schedule (daily or weekly) to catch any irregularities.

Finally, set up alerting for critical conditions. You might configure email or SMS alerts for certain events, such as detection of malware on a BAS workstation, or a controller going offline unexpectedly, or an access attempt from an unauthorized device. Early detection gives you a chance to intervene before an incident escalates. Remember that building operations often run 24/7 – cyber incidents can happen after hours, so monitoring should be continuous. By maintaining vigilance, you can catch intrusions or system misuse in their early stages. This step aligns with requirements from standards like the NIS2 Directive and ISO 27001 which emphasize continuous monitoring and incident detection capabilities for critical systems.

Key Actions:

• Enable and collect security logs from all building automation components (access logs, alarm logs, network device logs).

• Use monitoring tools to observe network traffic on the BAS segment and detect anomalies or new devices on the network.

• Set up intrusion detection systems (IDS/IPS) or security monitoring appliances tailored to industrial control networks to get alerts on suspicious activity.

• Regularly review logs and alerts, either manually or via a SIEM platform, to identify potential unauthorized access or changes.

• Establish alerting thresholds for critical events (e.g. numerous failed login attempts, configuration changes outside maintenance hours) so responsible staff are notified immediately.

Step 6: Prepare Incident Response and Recovery Plans

Despite all precautions, security incidents may still occur. A prepared organization can respond to and recover from incidents much more effectively, reducing downtime and damage. Develop a clear incident response plan that covers the building automation systems. This plan should define procedures for different scenarios – for example, what to do if malware is detected on a BAS server, or if a controller is hijacked and unresponsive, or if unauthorized access to the building network is suspected. Assign roles and responsibilities in advance: know who (IT security, facility management, external specialists, etc.) will take charge of containment, investigation, communication, and recovery in each case.

Include the building facilities team in incident response drills and planning. Their operational knowledge is crucial for decisions like isolating a segment of the building network or switching a system to manual backup mode. For instance, if a building’s HVAC control is compromised and starts malfunctioning, facilities personnel may need to override controls manually while IT contains the breach. Plan for such contingencies to maintain safety (e.g., manual emergency shutoff for equipment, or temporary procedures to operate lights and climate control without the central system if needed).

A vital component of recovery is regular data backups and system restoration capabilities. Back up configurations of controllers, the building management system database, historical trend data, and any other critical information. These backups should be stored securely offline or in a location isolated from the BAS network (so ransomware or an attacker cannot easily reach and encrypt/delete the backups). In practice, this might mean keeping a copy of each controller’s program on a secured server or external drive, and database backups on offline media.

Additionally, keep spare parts or fallback options for critical components. If a key controller or network switch is “bricked” (rendered unusable) by an attack, having a pre-configured spare can drastically reduce downtime. Document baseline configurations so that if systems need to be rebuilt from scratch, you have the necessary settings and software on hand. This level of preparedness can turn a potentially devastating attack into a manageable outage.

Communication and reporting are also part of incident response. Determine how you will inform stakeholders and possibly occupants if a cyber incident impacts building services. For example, if access control or elevators are affected, building occupants need timely information for safety. From a compliance standpoint, if you fall under regulations like NIS2 (which mandates reporting significant incidents in essential services), know the required notification timelines and authorities to contact. Being prepared in this manner ensures you handle incidents in a calm, methodical way rather than ad hoc chaos.

Key Actions:

• Develop a written incident response plan specifically for cybersecurity events in building automation systems, and ensure both IT and facilities teams are trained on it.

• Define clear roles (e.g., who isolates affected systems, who communicates with management or tenants, who interfaces with law enforcement or regulators).

• Maintain secure, offline backups of all critical BAS configurations and data. Verify these backups through periodic test restores.

• Keep spare hardware or firmware images for crucial devices to facilitate quick recovery or replacement if they are compromised.

• Conduct drills or tabletop exercises simulating BAS cyber incidents to practice your response and identify gaps in your plan.

• Ensure compliance with any incident reporting obligations (for instance, critical infrastructure operators under NIS2 must report substantial cyber incidents within a set time frame).

Step 7: Foster a Cybersecurity Culture and Align with Standards

Technology alone cannot guarantee security – it also requires an ongoing culture of cybersecurity and governance. This final step involves institutionalizing good security practices and continuously improving. Educate and train all personnel involved with building operations on the importance of cybersecurity. Facility managers, building engineers, and maintenance staff should understand basic cyber risks (such as phishing emails, USB malware, or poor password practices) as well as the specific policies in place for the building systems. Regular training sessions and awareness programs will help prevent mistakes that could lead to breaches. For example, training can cover why one should never plug unknown devices into the building network, or the procedure to follow if an unusual system alert appears.

Create formal policies and procedures for managing the building automation environment securely. This can include an acceptable use policy for the BAS (who is allowed to do what), a procedure for approving and documenting changes to control system settings (change management), and rules for connecting new devices to the network (ensuring they meet security requirements). Make cybersecurity a standard part of vendor selection and contracting: when hiring integrators or purchasing new building technology, include security criteria (such as compliance with IEC 62443 standards or providing regular software updates) in the requirements.

Align your building automation cybersecurity program with well-recognized frameworks and standards to ensure completeness. Implementing an Information Security Management System (ISMS) according to ISO/IEC 27001 can provide a governance structure – even though ISO 27001 is organization-wide, it should encompass building systems as part of the scope of information assets to protect.

he IEC 62443 series of standards offers detailed guidance specifically for industrial and automation control system security; these can be used as a reference for technical and process controls in a building context (for instance, IEC 62443-3-3 outlines system security requirements that can apply to a BAS deployment). In the European Union, the NIS2 Directive now mandates that many operators of essential services adopt risk management and cyber resilience practices – large or critical building facilities (like hospitals, data centers, transportation hubs) may fall under these rules. Even if not legally required, adhering to such standards elevates your cybersecurity maturity.

Think like an attacker: periodically, conduct vulnerability assessments or even hire ethical hackers to test the security of your building automation setup. The findings will show areas to improve and keep everyone on their toes. By treating cybersecurity as an integral part of operating a building (just like physical safety or maintenance), the whole team contributes to a more secure, resilient environment.

Key Actions:

• Provide ongoing cybersecurity training and awareness for facilities management teams and any staff who interact with building IT/OT systems.

• Establish clear security policies for building automation (covering password management, remote access, change control, incident reporting, etc.).

• Perform regular security audits or assessments of the building systems to ensure compliance with policies and identify new risks.

• Adopt industry standards and best practices: for example, manage your security program according to ISO 27001 and implement technical controls referencing the IEC 62443 framework.

• Stay updated on regulations (such as NIS2 in the EU or other local laws) that may impose cybersecurity requirements on building operations, and ensure your practices meet those requirements.

• Promote a culture of shared responsibility for cybersecurity, where every stakeholder from executives to on-site technicians understands their role in keeping the building systems safe.

FAQs 

How can I improve building automation cybersecurity in existing buildings?

• Improving cybersecurity in an existing building starts with assessing the current state. First, review all your building automation components (HVAC, lighting, elevators, etc.) and identify any weak points (outdated software, default passwords, open connections). Then implement the key steps outlined above: update default credentials to strong, unique ones; segment the network so building systems are isolated from office IT; apply all available security patches and firmware updates; enable firewalls and only allow necessary communication; and start monitoring the systems for any irregular activity. It’s also important to train your facility staff on security awareness so they follow best practices. By systematically addressing these areas, even an older building can drastically enhance its cybersecurity posture.

What are the common cyber threats to building automation systems?

• Building automation systems face many of the same threats as other networked devices, as well as some unique risks. Common cyber threats include malware infections (for example, ransomware or specialized ICS malware like Triton or Stuxnet) that can disrupt or take control of building equipment. Unauthorized access or hacking attempts are also a major threat – attackers might exploit weak passwords or vulnerabilities to gain remote control of a BAS. Insider threats or human error are a concern too (an employee might unintentionally download malware on a BAS workstation or misconfigure a system).

Which cybersecurity standards apply to building automation systems?

• Several established standards and frameworks can guide cybersecurity for building automation. ISO/IEC 27001 is an international standard for information security management – it provides a high-level framework that can include building systems as part of an organization’s overall security program. IEC 62443 is a family of standards specifically for industrial automation and control system security; these are highly relevant to BAS since building controls are a type of control system. The IEC 62443 standards outline best practices for system design, implementation, and maintenance to achieve different security levels.

Is it true that smart buildings are more vulnerable to cyber attacks?

• “Smart” buildings (those with extensive automation and IoT integration) have more digital entry points, so they can be more exposed to cyber attacks than traditional buildings, but it depends on how well they are secured. In a traditional building with minimal connectivity, the cyber risk was low simply because systems were isolated. Once you introduce networked sensors, remote control, and integration with IT networks or cloud services, the building gains tremendous efficiency and functionality – but yes, it also becomes a target for hackers.

Conclusion

In conclusion, strengthening Building Automation Cybersecurity requires a multi-layered approach and commitment from both technology and people. We outlined seven essential steps: knowing your systems and risks, securing access controls, isolating networks, hardening and patching devices, monitoring for threats, preparing for incidents, and cultivating a security-focused culture. By following these steps, any facility – whether it’s an office skyscraper, a factory, an apartment complex, or a mixed-use campus – can significantly improve its resilience against cyber attacks.

The goal is to protect not only the digital assets, but also the physical safety, comfort, and business continuity that depend on secure building operations. Cybersecurity is an ongoing process: as buildings become smarter and threats evolve, continuously revisit and refine your security measures. With diligent effort and adherence to best practices and standards, building automation systems can be operated safely and reliably in today’s connected world.