ZTNA Explained: Why Zero Trust Network Access Is Replacing VPNs

58% of ransomware attacks in 2024 started with compromised security appliances, including VPN devices. The problem isn't user error; it's the fundamental way VPNs grant access.

Virtual Private Networks (VPNs) were built for a world that no longer exists. They assume employees work from offices and trust anyone who makes it past the login screen. One compromised credential now gives attackers free rein across your entire network.

Zero Trust Network Access (ZTNA) takes the opposite approach. It continuously verifies every access request and grants permission only to specific applications, never to your entire network.

After analyzing deployment data from enterprise implementations and comparing security architectures, we found that ZTNA doesn't just patch VPN vulnerabilities; it also addresses broader security challenges. It eliminates the trust-based model that enables those vulnerabilities.

This guide explains how ZTNA works, why leading organizations are making the switch, and what your migration path should look like.

The Problem with Traditional VPNs

VPNs were designed for a different era. They assume that once you authenticate, you deserve access to the entire network. This "castle-and-moat" approach made sense when everyone worked in offices and most applications lived in data centers.

Here's how VPNs create security gaps:

Problem #1: Implicit Trust After Login

VPNs authenticate you once at the start. After that initial check, they trust you completely.

If someone steals your credentials or compromises your device, they get the same access you have. No additional verification happens during your session.

Problem #2: Network-Wide Access

VPNs typically grant access to entire network segments. You might only need one application, but you can see and potentially access dozens of other systems. This creates unnecessary exposure.

Attackers love this setup because they can move laterally across your network once they get in.

Problem #3: Limited Visibility

Most VPN solutions provide minimal insight into what users do after they connect. You know someone logged in, but tracking their specific activities requires additional tools and complex configurations.

Problem #4: Performance Issues

VPN traffic often routes through central hubs, creating bottlenecks. Users experience slower connections, especially when accessing cloud applications. The extra latency frustrates employees and reduces productivity.

Problem #5: Scalability Challenges

As organizations adopt more cloud services, VPNs struggle to keep up.

Each new application or cloud environment requires additional configuration. Managing multiple VPN concentrators across different locations becomes unwieldy.

According to Cybersecurity Insiders' 2024 VPN Risk Report, 56% of organizations and enterprises experienced one or more cyberattacks exploiting VPN vulnerabilities in the past year, underscoring that traditional VPNs are increasingly ineffective at securing remote access.

Meanwhile, 78% of organisations plan to implement Zero Trust strategies within the next 12 months to protect remote access environments better.

Understanding Zero Trust Principles

Zero trust starts with a simple premise: never trust, always verify.

It assumes that threats exist both outside and inside your network perimeter. Every access request requires verification, regardless of its source.

The core principles include:

• Verify explicitly: Always authenticate and authorize based on all available data points
• Use least privilege access: Give users only the access they need for their current task
• Assume breach: Act as if attackers have already compromised your environment

These principles might sound abstract, but ZTNA makes them concrete and actionable.

How ZTNA Works

Understanding what is ZTNA and how does it work requires examining its technical architecture and workflow.

ZTNA applies zero-trust principles to network access. Instead of connecting users to networks, it connects users to specific applications.

A. The Authentication Flow

When you try to access an application through ZTNA, several things happen quickly:

Step 1: The system verifies your identity.

The initial step usually involves single sign-on (SSO) or multi factor authentication (MFA). Your username and password aren't enough; you need a second factor, such as a phone app or a security key.

Step 2: The system checks your device.

Is your operating system up to date?

Do you have current security patches?

Is your antivirus software running?

The system evaluates your device against company security policies.

Step 3: The system evaluates the context.

Where are you connecting from?

What time is it?

Does this access request match normal user behavior patterns?

All these factors influence the access decision.

B. Policy Enforcement

ZTNA uses detailed policies to control access.

These policies consider:

• Who you are (your identity and role)
• What device are you using
• Where are you're connecting from
• When you're accessing the resource
• Which application do you need
• How sensitive the data is

The system matches your request against these policies in real-time. If everything checks out, it creates an encrypted connection directly to the specific application you need. Nothing else becomes visible or accessible to you.

Policies are often role-based (RBAC) and context-driven; dynamically adapting based on risk signals such as device health or login location.

This fine-grained control reduces exposure and simplifies compliance.

C. Continuous Monitoring

ZTNA doesn't stop checking after you connect. It continuously monitors your session for suspicious network activity. If something changes, your device becomes non-compliant, your behavior looks unusual, or the risk level increases, the system can adjust or revoke access immediately.

ZTNA vs. VPN: The Key Differences

Below is a quick comparison that summarizes the shift from VPNs to ZTNA:

The differences go beyond features. ZTNA represents a different security philosophy. VPNs ask, "Are you allowed on the network?" ZTNA asks, "Should you access this specific resource right now?"

Real Business Benefits

Organizations implementing ZTNA see concrete improvements:

Security Improvements

ZTNA makes applications invisible to the internet. Attackers can't target what they can't see. Even if someone compromises a user account, they can only access the specific applications that the user needs. Lateral movement becomes nearly impossible.

Your security team gains better visibility, too. They can see exactly which applications each user accesses, when they connect, and what they do during sessions. This detailed logging helps with compliance requirements and incident investigation.

Operational Advantages

ZTNA simplifies remote access management. You don't need separate VPN concentrators for each office location.

Users don't manually connect and disconnect. The system handles authentication and access automatically based on your policies.

Cloud application performance improves significantly. Instead of routing traffic through a central VPN hub, users connect directly to cloud services. This minimizes latency and improves the user experience.

According to Gartner, by 2025, 70% of new remote access deployments will use ZTNA instead of traditional VPNs. Organizations recognize the operational and security advantages.

Common Use Cases

Remote workforce enablement is the most obvious use case. Employees can securely access applications from anywhere without compromising security.

Third-party access becomes simpler, too. Instead of giving contractors VPN credentials with broad network access, you grant them access only to the specific applications they need. When the project ends, you revoke their access.

Mergers and acquisitions also benefit from ZTNA. You can quickly provide acquired company employees access to necessary applications without merging entire networks.

Implementation Considerations

Moving from VPN to ZTNA requires planning. Most organizations take a phased approach.

A. Migration Strategies

1. Start Small

Begin with cloud-based applications. These are easiest to protect with ZTNA since they're already outside your traditional network perimeter. Pick a few non-critical applications to test your implementation first.

2. Run Both Systems

Keep your VPN running while you roll out ZTNA. This parallel operation lets users fall back to VPN if they encounter issues. It also gives you time to migrate legacy applications that might need special handling.

3. Focus on User Experience

ZTNA should make access easier for users, not harder. If your implementation creates friction, users will find workarounds that compromise security. Test thoroughly with real users before full deployment.

4. Build Clear Policies

ZTNA's power comes from granular policies.

You need to decide:

• Which users need access to which applications
• What device security standards do you enforce
• How you'll handle different risk scenarios
• What to do when policies conflict

Policy design takes time. Involve stakeholders from IT, security, and business units in the process.

5. Address Legacy Applications

Some older applications might not work well with ZTNA. Identify these early and develop migration plans. You might need to modernize some applications or temporarily maintain VPN access for specific legacy systems.

6. Train Your Team

Both IT staff and end users need training. IT teams must understand policy management and troubleshooting. Users need to know how the new system works, even if it's mostly transparent to them.

B. Technical Requirements

• Integration with identity providers (e.g., Okta, Azure AD).
• Endpoint management and device posture validation.
• Network infrastructure that supports micro-segmentation.
• Comprehensive application inventory and discovery.

C. Common Challenges

Organizations implementing ZTNA face predictable hurdles:

• Complexity: ZTNA introduces new components and concepts. Your team needs time to learn the technology and develop expertise.
• Initial Costs: ZTNA requires investment in new infrastructure and tools. However, organizations often recover these costs by reducing VPN infrastructure and improving their security posture.
• Integration Work: ZTNA needs to connect with your identity provider, endpoint management system, and other security tools. These integrations require planning and testing.
• Change Management: Users resist change, especially if they don't understand the benefits. Clear communication about why you're implementing ZTNA helps smooth the transition.

ZTNA adoption is as much a people-and-process change as it is a technology upgrade.

The Future of Network Access

A. Industry Trends

ZTNA is evolving rapidly. Many vendors now integrate it into Secure Access Service Edge (SASE) platforms for unified control.

Artificial intelligence (AI) and machine learning are increasingly used to fine-tune access policies based on behavior patterns.

B. Beyond “VPN Replacement”

ZTNA isn’t just a newer VPN; it’s a foundational component of zero-trust architecture. It extends protection beyond remote users to on-premises systems, APIs, and IoT devices.

C. Predictions

• Most large enterprises will implement ZTNA within the next few years.
• VPNs may persist for niche use cases, but adoption will decline sharply.
• Expect consolidation as universal ZTNA standards mature across vendors.

The shift is inevitable as organizations prioritize user identity-centric security over network-centric access controls.

Conclusion

VPNs served us well for years, but the world changed.

Remote work became permanent. Cloud adoption accelerated. Cyber threats have evolved. VPNs can't adequately address these modern challenges.

ZTNA offers a better approach. It provides stronger security through continuous verification and least-privilege access control. It improves user experience with seamless, transparent connections. It simplifies operations by eliminating complex VPN infrastructure.

The transition won't happen overnight. Most organizations will run VPNs and ZTNA in parallel for months or even years. That's fine.

Start with a pilot program. Learn what works in your environment. Build expertise gradually.

The shift from network-centric to identity-centric security isn't optional anymore. Organizations that embrace ZTNA solution now will be better positioned to handle tomorrow's security challenges. Those who cling to VPNs will find themselves increasingly vulnerable and operationally constrained.

Your next step is simple: evaluate ZTNA as part of your broader security strategy. Identify applications that could benefit from ZTNA protection. Talk to your team about what a migration path might look like for your organization.

The technology is mature. The benefits are clear. The time to act is now.