VPN vs. Zero Trust: Why One Big Lock Isn’t Enough
When the world went into lockdown in 2020, the Virtual Private Network (VPN) became the unsung hero of the global economy, providing a digital lifeline that allowed millions to work from their kitchen tables. For years, organizations have leaned on VPNs as a primary line of defense. Safely browsing from a local coffeeshop or uploading the last touches to a spreadsheet before boarding a plane. The logic made sense to me at the time: if you put a steel door and a strong lock at the entrance of your digital castle, only trusted people can get inside. However, as remote work shifted into a permanent hybrid reality, the limitations of this “connect once, trust forever” model became glaringly apparent. Today’s threat landscape has changed, and that old model leaves far too much room for trouble once someone slips past the gate.
A VPN is essentially that big steel door and heavy lock on your castle’s main entrance. It creates a safe tunnel for access to your environment, encrypts traffic, shields users from prying eyes, and ensures that only authenticated users can enter the network. That’s valuable, but it’s also where the protection stops for most customers. Once a user, legitimate or malicious, gets inside, the VPN doesn’t stop them from wandering freely through every hallway and room. This could mean laterally moving through the network or escalating right up to the C-suite floors. If an attacker compromises a single device or steals a set of credentials, they inherit the same open access. Your entire castle becomes fair game.
Zero Trust architectures flip that model on its head. Instead of assuming that anyone inside the walls is trustworthy, Zero Trust assumes the opposite: trust no one, verify everything. In castle terms, Zero Trust doesn’t just lock the front door, it places locks on every room, every closet, every vault. Each time someone tries to enter a new space, they must prove they belong there. Identity, device health, location, and behavior patterns each becomes part of the decision to grant or deny access.
This approach dramatically limits the blast radius of a breach. Even if an attacker manages to get inside your castle, they can’t simply roam around. They hit locked doors at every turn. Sensitive rooms and your crown jewels remain protected behind multiple layers of verification. Instead of relying on a single perimeter defense, Zero Trust distributes security throughout the entire environment.
The difference between a VPN and Zero Trust isn’t just technical, it’s philosophical. A VPN is built on the idea of “inside equals safe.” Zero Trust recognizes that in a world of phishing attacks, compromised devices, insider threats, and cloud-based systems, that assumption no longer holds true. Modern security requires continuous validation, granular access control, and the ability to limit movement even after authentication.But let’s cut to the chase. For many of us, Zero Trust implementation is no longer an option. Executive Order 14028 directed all federal agencies to transition to Zero Trust architectures and principles as a part of an overarching plan to better secure American networks and data. In turn, states, local governments, and educational institutions are releasing similar directives of their own. In fact, I would wager that you are reading this article because your own organization is making this transition (or needs to start now). If you are struggling and relying on outdated technology but need to reach Zero Trust maturity in 2027, there is an innovative solution built just for you by Tensley Consulting. ZT ROAM is the first commercially available Outcome-Based Assessment Tool to measure an organization’s ability to defend against attacks using Zero Trust architectures and principles. It is automated, objective, and exports a government accepted compliance report instantly. Whether you need to achieve 91 Target activities from the DoD Zero Trust Strategy or reach the Optimal ZT maturity level of the CISA Zero Trust Maturity Model, ZT ROAM can help your organization become compliant faster and with the confidence to know your data is protected.
If you want to know more about how we at Tensley Consulting construct and assess Zero Trust architectures, visit our website and check out our next article focusing on the value of automated outcome-based assessments over traditional compliance checklists.
Written by:
CPT William Johnson (U.S. Army Ret.) & Dr. David Moured Ph.D.