Zero Trust VPN: Meaning and Alternatives

Any cybersecurity professional would agree that traditional Virtual Private Networks (VPNs) are insufficient for modern security demands. One of the key reasons for this shift is the emergence of the zero-trust security model, which fundamentally challenges the assumptions upon which VPNs are built. This article explores what Zero Trust is, why VPNs are incompatible with Zero Trust principles, and what alternatives organizations should consider.

What is a Zero Trust VPN?

Zero Trust VPN means a virtual private network service that works on the principle of "never trust, always verify." This model requires continuous verification of user identities, devices, and access requests, regardless of their location within or outside the network. Although some VPN providers claim to offer Zero Trust VPN, in reality, most VPNs lack some core features and the users need to buy extra security products/services to implement the Zero Trust model.

Why VPNs Are Incompatible with Zero Trust Architecture

Traditional VPNs were designed with the assumption that once a user or device is authenticated, they can be trusted throughout their session. However, this approach is fundamentally at odds with the Zero Trust philosophy for several reasons.

1. Lack of Continuous Verification

VPNs typically authenticate users at the beginning of a session. Once authenticated, the user is granted access to a broad range of resources without further checks. This lack of continuous verification in so-called zero-trust VPNs creates significant security risks. If a user's credentials are compromised, an attacker can potentially access sensitive data without any additional verification checks. Zero Trust, on the other hand, demands continuous authentication and authorization, ensuring that each access request is independently verified.

2. Lack of Context-Based Access

VPNs generally do not account for the context in which access requests are made. They lack the ability to differentiate between a legitimate user accessing data during regular working hours and a potential intruder attempting to access the same data at an odd time or from an unusual location. Zero Trust models incorporate context-aware access, where decisions are made based on factors such as the user's role, what groups the user belongs to, the sensitivity of the data, the device used, and the user's location. This contextual awareness is critical in preventing unauthorized access and minimizing the potential attack surface.

3. Broad Network Access

Once connected to a VPN, users often have access to a wide range of network resources. This broad access violates the principle of least privilege, which is central to Zero Trust. In contrast, zero-trust architectures enforce the principle of least privilege by granting users only the access necessary to perform their tasks, minimizing the potential damage in case of a breach.

Zero Trust VPN Alternatives

Given the limitations of traditional VPNs, organizations are increasingly looking for alternatives that align with Zero Trust principles. Here are some key technologies that can serve as more effective solutions:

1. Identity-Aware Proxies (IAPs)

Identity-aware proxies, like Pomerium, provide a more granular approach to access control by verifying user identity and context before granting access to specific applications or resources. Unlike VPNs, IAPs do not grant broad network access but instead enforce strict access controls based on user roles and contextual data like the user’s 

• location, 

• device security status, and 

• IP address. 

This aligns with the Zero Trust principle of least privilege.

It also offers continuous verification, which is a core Zero Trust concept. Unlike so-called zero-trust VPNs that only verify a user's identity and authorization at the start of a session, IAP tools like Pomerium continuously verify every action based on authentication, authorization, and contextual factors before granting or denying access. 

2. Software-Defined Perimeter (SDP)

Software-defined perimeter solutions create a dynamic, user-specific network perimeter based on Zero Trust principles. SDPs authenticate users and devices before granting access and continuously monitor for potential threats during the session. This approach ensures that access is tightly controlled and that any suspicious activity can be quickly detected and addressed.

3. Secure Access Service Edge (SASE)

Secure Access Service Edge combines network security functions with WAN capabilities to support the dynamic secure access needs of modern organizations. SASE solutions typically include Zero Trust Network Access (ZTNA), which replaces traditional VPNs with a more secure, context-aware, and scalable solution. By enforcing Zero Trust policies, SASE ensures that access is tightly controlled based on user identity, device health, and context.

4. Privileged Access Management (PAM)

Privileged Access Management tools enforce strict access controls for users with elevated privileges, ensuring that even highly trusted users are continuously verified. PAM solutions can integrate with Zero Trust frameworks to ensure that privileged access is only granted under specific, well-defined conditions.

Conclusion on Zero Trust VPN

As cyber threats become more sophisticated, the limitations of traditional VPNs become increasingly apparent. While the Zero Trust architecture offers a more robust security model by emphasizing continuous verification, context-based access, and the principle of least privilege, the so-called zero-trust VPNs are often unable to meet these needs. Organizations looking to enhance their security posture should consider alternatives to VPNs that align with Zero Trust principles, such as Identity-Aware Proxies, Software-Defined Perimeters, Secure Access Service Edge, and Privileged Access Management solutions. These technologies offer a more secure, flexible, and scalable approach to protecting sensitive data in today's complex digital environment.