Smart Buildings Academy Podcast | Formerly Building Automation Monthly Podcast

SBA 546: VPN and Remote Access in BAS

Written by Smart Buildings Academy | May 21, 2026 12:00:00 PM

Episode Description:

Remote access is no longer optional in building automation. But every connection to your BAS can also become a pathway for risk if security is treated as an afterthought.

In this episode, you’ll learn how VPNs, remote desktop tools, and zero trust strategies are reshaping the way automation professionals manage buildings remotely. You’ll also hear why many BAS networks remain vulnerable and where even experienced teams make costly mistakes.

Topics Covered
• Why BAS cybersecurity is different from traditional IT security
• The real differences between site-to-site, client-to-site, and zero trust access
• How network segmentation protects building systems from larger threats
• Common remote access mistakes that create hidden vulnerabilities
• What a practical and secure remote access strategy should include

As building systems become more connected, the challenge is no longer just enabling access. It’s securing it without compromising operations.

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Securing Remote Access in Building Automation Systems with VPNs and Zero Trust 

Remote access has become a standard expectation in modern building automation systems. Facility teams want visibility from anywhere. Service providers need the ability to troubleshoot remotely. Owners expect cloud analytics, dashboards, and centralized oversight across portfolios.

At the same time, every remote connection creates a potential entry point into operational technology systems.

Building automation systems were never originally designed for internet connectivity. Many systems still operate with legacy controllers, outdated firmware, proprietary protocols, and long upgrade cycles. As connectivity expands, cybersecurity risks increase alongside convenience.

In this episode, we break down the fundamentals of VPNs, secure remote access strategies, and the security pitfalls that continue to expose BAS environments.

Why Building Automation Systems Are Different

Traditional IT security practices do not always translate cleanly into operational technology environments.

Building automation systems contain devices that often remain in service for decades. Many controllers cannot tolerate downtime for frequent patching or upgrades. Some devices were built long before cybersecurity became a priority.

A typical BAS network also contains multiple layers:

  • Field devices like sensors, actuators, and VFDs
  • Automation controllers such as PLCs and DDCs
  • Supervisory front-end platforms
  • Enterprise integrations and cloud platforms

Each layer introduces different risks and different access requirements.

Treating the entire BAS environment like a flat IT network creates major vulnerabilities.

What a VPN Actually Does

A VPN, or Virtual Private Network, creates an encrypted tunnel between two endpoints across a public network.

The purpose is simple:

  • Protect data while it travels across the internet
  • Prevent unauthorized interception
  • Secure remote access to private systems

The episode explains several common VPN architectures used in building automation:

Site-to-Site VPNs

These create permanent encrypted connections between locations, such as a remote facility and a central operations center.

They are commonly used for:

  • Multi-site building portfolios
  • Corporate integrations
  • Continuous monitoring environments

Client-to-Site VPNs

These allow individual users to securely connect to a BAS network remotely from laptops or mobile devices.

This is the most common approach for technicians and facility operators working remotely.

Zero Trust Network Access

Zero trust takes a different approach entirely.

Instead of granting broad network access, users only receive access to specific resources for limited periods of time.

For example:

  • A technician may gain temporary access to one controller
  • Access may expire automatically after two hours
  • All activity may be fully logged and recorded

Everything else on the network remains invisible.

Why Network Segmentation Matters

One of the most important concepts covered in the episode is network segmentation.

Many BAS environments still operate on flat networks where building systems sit too close to corporate IT infrastructure.

That creates unnecessary risk.

A properly segmented architecture separates:

  • Corporate IT systems
  • BAS supervisory systems
  • BAS control networks
  • Remote access termination zones
  • Cloud integrations

Segmentation limits exposure when a compromise occurs.

If an attacker gains access to one segment, they cannot automatically move throughout the entire environment.

Defense in depth becomes essential for operational technology security.

The Biggest Remote Access Mistakes

The episode also highlights several common failures that continue to appear in BAS deployments.

Treating Security as a One-Time Project

A VPN installed years ago without updates becomes a liability.

Remote access infrastructure requires:

  • Ongoing maintenance
  • Patch management
  • Credential reviews
  • Continuous monitoring

Security is an operational responsibility, not a completed task.

Bypassing Secure Access Methods

Convenience often creates risk.

When users avoid VPNs because they are slow or difficult to use, they may create unauthorized workarounds using tools like remote desktop sharing applications.

These shortcuts often bypass security controls entirely.

Exposing Remote Desktop Directly to the Internet

Remote Desktop Protocol remains one of the most exploited attack vectors in operational technology.

Any remote desktop solution should sit behind secure access controls such as:

  • VPNs
  • Zero-trust platforms
  • Multi-factor authentication

Direct internet exposure creates unacceptable risk.

Failing to Involve IT and Security Teams Early

Controls professionals understand BAS operations extremely well. Cybersecurity, however, is its own discipline.

Strong remote access strategies require collaboration between:

  • Building automation teams
  • IT departments
  • Cybersecurity professionals

The best results happen when security planning begins during system design, not after deployment.

The Growing Importance of Zero Trust

Zero-trust architecture is gaining momentum because it aligns well with operational technology security goals.

Instead of assuming users should trust the network once connected, zero trust continuously verifies:

  • Who the user is
  • What they need access to
  • How long do they need it
  • Whether their activity is appropriate

This significantly reduces the impact of compromised credentials or insider threats.

As BAS environments continue moving toward cloud connectivity, centralized management, and remote service delivery, zero trust models will likely become more common across the industry.

Remote Access Requires Discipline

Connectivity delivers real operational value.

Remote monitoring, cloud analytics, digital twins, and centralized management platforms can improve efficiency and reduce service costs.

But connectivity without security creates exposure.

A secure BAS remote access strategy should include:

  • Network segmentation
  • Proper VPN architecture
  • Multi-factor authentication
  • Access governance
  • Logging and monitoring
  • Regular patching
  • Clear documentation

The organizations that succeed will be the ones that balance operational flexibility with disciplined cybersecurity practices.

Building automation systems are no longer isolated systems sitting quietly inside buildings. They are connected operational platforms that require the same level of security attention as any critical infrastructure environment.

For a deeper discussion and insights from the field, listen to this episode on the Smart Buildings Academy podcast.