Zero Trust vs VPN: Rethinking Remote Access Security

The Premise That Separates These Two Approaches

Every remote access security model rests on a foundational assumption about trust. Traditional VPNs assume that users who successfully authenticate to the VPN gateway can be trusted to access network resources — the "castle and moat" model, where getting past the drawbridge means you are inside the trusted zone. Zero Trust Network Access (ZTNA) assumes the opposite: trust nothing and no one by default, regardless of network location. Every access request — from any user, device, or application, on any network — is evaluated continuously against identity, device health, and context before access is granted.

That difference in starting assumptions produces security architectures that diverge significantly in their risk profiles, especially for the distributed workforce patterns that have become standard across US businesses since 2020.

How Traditional VPNs Work — and Where They Fall Short

A VPN creates an encrypted tunnel between a remote device and a corporate network gateway. Once established, the user typically receives an IP address inside the corporate network and can reach resources as if physically on-premises. For the threat landscape of the early 2000s — where remote access was occasional, the workforce was small, and devices were corporate-managed — this was a reasonable model.

The risk profile of VPNs in 2025 reflects a different threat environment:

• Broad network access after authentication: A compromised VPN credential gives an attacker lateral movement across the internal network. The 2020 SolarWinds attack and the 2021 Pulse Secure VPN exploits demonstrated how systematically this weakness is exploited.
• Device health is not evaluated: Traditional VPNs authenticate the user but generally do not assess the security posture of the connecting device. A personal laptop with outdated software, no EDR, and an active malware infection can connect to the corporate network if the user's credentials are valid.
• Attack surface on the VPN concentrator itself: VPN gateways are internet-facing and frequently targeted. CVE databases consistently list high-severity vulnerabilities in major VPN products; the Cybersecurity and Infrastructure Security Agency (CISA) has issued multiple advisories specifically warning that nation-state actors are actively exploiting known VPN vulnerabilities in US critical infrastructure.
• Performance and scalability challenges: Routing all remote traffic through a central gateway creates bandwidth bottlenecks and latency — a problem that became acute when large fractions of US workforces shifted to remote work and VPN infrastructure was not designed for that throughput.

How Zero Trust Network Access Works

ZTNA, codified in NIST Special Publication 800-207, replaces the network perimeter with a policy enforcement model. Rather than connecting users to a network, ZTNA connects authenticated, authorized users to specific applications — and nothing else. Key characteristics include:

• Identity-centric access: Every access request is authenticated against an identity provider (such as Microsoft Entra ID or Okta) and evaluated against role-based access policies. The same user may have different levels of access depending on device posture, location, and time of day.
• Device posture assessment: Before granting access, ZTNA solutions evaluate whether the connecting device meets defined security requirements — patch level, EDR agent status, disk encryption, and so on. Non-compliant devices are denied or redirected to remediation.
• Least-privilege application access: Users see and can reach only the specific applications they are authorized to use. There is no concept of "being on the network" — lateral movement is structurally prevented because there is no network to move laterally across.
• Continuous verification: Trust is not established once at login and then assumed for the duration of a session. Signals are evaluated continuously; anomalous behavior (unusual data volume, access from a new location, changed device posture) can trigger step-up authentication or session termination.
• No internet-exposed gateway: ZTNA connectors initiate outbound connections to a cloud broker, which means there is no VPN concentrator with a public IP address for attackers to target with known vulnerabilities.

Direct Comparison: VPN vs. Zero Trust

• Trust model — VPN: implicit trust after authentication. Zero Trust: explicit, continuous verification of every request.
• Access scope — VPN: broad network access. Zero Trust: specific application access only.
• Device evaluation — VPN: typically not assessed. Zero Trust: device posture is a condition of access.
• Lateral movement risk — VPN: high; compromise of one credential can reach many resources. Zero Trust: structurally low; users cannot reach resources they are not authorized for.
• Attack surface — VPN: internet-facing concentrator, frequently targeted. Zero Trust: no public-facing gateway.
• Scalability — VPN: central gateway bottleneck. Zero Trust: cloud-native, distributed, scales with demand.
• Visibility — VPN: limited behavioral telemetry. Zero Trust: continuous session monitoring with rich access logs.
• User experience — VPN: often slow, connection drops, split-tunnel complexity. Zero Trust: generally transparent, faster for SaaS-heavy environments.

The US Regulatory and Guidance Context

Federal guidance has aligned behind Zero Trust for several years. Executive Order 14028 (May 2021), which mandated cybersecurity improvements across the federal government, explicitly called for federal agencies to adopt Zero Trust architecture. CISA's Zero Trust Maturity Model and the Office of Management and Budget's M-22-09 memorandum set specific ZTNA migration targets for federal agencies. While these mandates apply to federal entities, they signal the direction of US cybersecurity policy and are increasingly echoed in the expectations of federal contractors, regulated industries, and cyber insurers.

When Traditional VPNs Still Have a Role

Zero Trust is not a universal replacement for VPN in every scenario. Site-to-site connectivity between physical locations, legacy applications that require network-level access and cannot be proxied through an application connector, and OT/ICS environments with specialized protocol requirements may still require VPN as part of the connectivity architecture. The most pragmatic approach for most US organizations is a hybrid transition: deploying ZTNA for user-to-application access while maintaining site-to-site VPN where structurally required, and gradually migrating legacy applications as they are modernized.

The Business Implications of the Shift

For US business and technology leaders, the choice between VPN and ZTNA is not purely technical — it carries material business implications. Cyber insurers increasingly view ZTNA favorably relative to VPN-dependent architectures, particularly in the context of ransomware underwriting. A breach that originates through a compromised VPN credential and results in broad lateral movement will face hard questions about why network-level access was granted without device posture checks. Regulators in healthcare, financial services, and critical infrastructure are moving in the same direction.

GR IT Services advises US organizations on remote access security strategy — from evaluating current VPN risk exposure to developing a phased ZTNA adoption roadmap. To discuss your organization's remote access architecture, reach out to our team at inquiry@gritservices.io.