What is Zero Trust Network Access?

Zero Trust is a cybersecurity model based on a simple, powerful idea: never trust, always verify.

Unlike traditional security models that assume users and devices inside a corporate network are trustworthy, ZTNA assumes that no entity—inside or outside the network—should be trusted by default. Every access request is rigorously authenticated, authorized, and continuously validated every time access is granted.

ZTNA emerged as a response to the evolving threat landscape, where traditional perimeter-based security models have become inadequate. As cyber threats have grown more sophisticated, exploiting vulnerabilities within supposedly trusted networks, the need for a more robust and comprehensive security approach has become clear. ZTNA minimizes these risks by reducing the attack surface and implementing stringent verification processes.

According to the National Institute of Standards and Technology (NIST), Zero Trust Architecture (ZTA) shifts security away from static perimeters and toward protecting individual users, assets, and resources.

Learn more with Neeve Podcast: Zero Trust Architecture and ZTNA

At the heart of Zero Trust is the understanding that breaches are inevitable—and preparation is key. Here’s what sets this model apart:

• Continuous Verification
  Every user and device must prove they’re safe, every time. It’s not one-and-done.

• Least Privilege Access
  Users and systems only get access to the exact resources they need—nothing more.

• Microsegmentation
  Networks are broken into smaller zones, so one breach doesn’t open the door to everything.

• Multi-Factor Authentication (MFA)
  Multiple layers of identity checks reduce the risk of unauthorized access.

• Assume Breach
  Operate as if attackers are already inside—and build your defenses accordingly.

Advantages of ZTNA Compared to Traditional Security Models

Traditional security models rely heavily on strong perimeter defenses, assuming threats primarily come from outside the organization. Once inside the network, users and devices were often granted broad access based on their position within the network, with minimal internal segmentation. This approach is akin to having a strong outer wall but leaving internal doors unlocked.

Vulnerabilities in Traditional Models

• Implicit Trust: If a bad actor breaches the perimeter, they can move laterally within the network with minimal resistance.
• Static Security Policies: Traditional models often use static security policies that do not adapt to the dynamic nature of modern networks, where users and devices frequently move across different locations.
• Lack of Internal Visibility: Once inside the network, there is often limited visibility into what is happening, making it difficult to detect and respond to threats quickly.

Zero Trust Network Access is the practical application of Zero Trust principles to remote access. Instead of giving broad access to a network like a VPN does, ZTNA grants access to specific applications, for a specific session, for a verified user on a verified device.

Here’s how it works in practice:

• Identity and Access Management (IAM)
  Each user and device is authenticated using identity providers, certificates, or directory services.

• Device Posture Checks
  ZTNA confirms that a device is healthy, secure, and compliant before allowing access.

• Per-Session Access
  Access is dynamically granted per application, per session—no open-ended network access.

• Encrypted Tunnels
  All communication is encrypted (typically using AES-256), protecting data in transit.

• Real-Time Monitoring
  ZTNA systems watch for anomalies and can shut down or adjust access automatically.

ZTNA vs. VPN: What’s the Difference?

For businesses and building operators, Zero Trust isn’t just a security upgrade—it’s a smarter way to run infrastructure.

• Enhanced Security
  Attackers can’t exploit broad network access—they’re stopped at the door.

• Remote-Ready
  ZTNA is ideal for hybrid and remote teams. No client installs, no VPN complexity.

• Improved Compliance
  Audit trails and role-based access make compliance easier and more defensible.

• Operational Efficiency
  Fewer truck rolls. Faster troubleshooting. More secure vendors and contractors.

• Happier Users
  ZTNA works quietly in the background, giving users fast, frictionless access.

The Unique Challenges of OT Security

Operational Technology (OT) refers to hardware and software that detects or causes changes through direct monitoring and control of physical devices, processes, and events within industrial settings. This includes systems like Building Management Systems (BMS), Industrial Control Systems (ICS), and Supervisory Control and Data Acquisition (SCADA) systems.

OT environments present unique security challenges:

• Legacy Systems: Many OT systems are legacy technologies designed before cybersecurity was a major concern. They often lack built-in security features and cannot be easily updated.
• Low latency Systems: OT systems typically have flat architecture to reduce latency in communications between devices. These flat architectures leave networks vulnerable to lateral movement.
• Interconnected Systems: Modern OT environments are increasingly interconnected with IT systems, exposing OT networks to the broader internet and increasing their vulnerability to cyberattacks.
• High Availability Requirements: OT systems often control critical infrastructure (like HVAC systems, energy management, and manufacturing processes), where downtime can have significant safety and financial consequences. This makes traditional patching and updating approaches challenging.

ZTNA’s Role in Enhancing OT Security

1. Protection Against Lateral Movement: ZTNA’s strict access controls are particularly beneficial in OT environments. If one access point is compromised, ZTNA ensures that the attacker cannot easily move laterally to other parts of the network.
2. Securing Legacy Systems: ZTNA can be implemented in front of legacy OT systems, adding a layer of security without requiring changes to the underlying systems. This is crucial in environments where legacy systems cannot be easily updated or replaced.
3. Real-Time Monitoring: Continuous monitoring and threat detection capabilities of ZTNA are critical in OT environments, where real-time response to anomalies is essential to prevent catastrophic failures.
4. Compliance and Risk Management: ZTNA helps OT environments comply with increasingly stringent cybersecurity regulations. By implementing strict access controls and ensuring that every access request is verified and logged, organizations can demonstrate adherence to industry standards and reduce their liability in the event of a breach.

In smart buildings, where Building Management Systems (BMS) and other OT systems are integrated with IT networks, ZTNA is essential. The integration of IoT devices, cloud services, and AI-driven analytics creates a complex network environment where traditional security models are inadequate. ZTNA provides the necessary security framework to manage these complexities, ensuring that each device and user is authenticated and that their actions are continuously monitored and controlled.

Getting started doesn’t mean starting from scratch. Here’s how to begin:

1. Define Your Protect Surface
   Identify your most valuable data, systems, and services.

2. Map Transaction Flows
   Understand how users and devices interact with those critical assets.

3. Design with Microsegmentation
   Segment your network around assets, not just zones.

4. Create Access Policies
   Define the “who, what, when, where, why, and how” for each access request.

5. Continuously Monitor and Adapt
   Use analytics and alerts to evolve your policies over time.

How to Choose a ZTNA Solution

When evaluating providers, look for:

Granular Access Control
Support for context-based policies tied to user, device, time, and location.

Cloud-Native Design
Don’t bolt Zero Trust onto an old platform—choose a vendor built for modern infrastructure.

Vendor Integrations
Seamless integration with your IAM, SIEM, and endpoint tools makes adoption easier.

Unified Agent (Optional)
Some platforms offer both VPN and ZTNA in one agent for a smoother transition.