Zero trust architecture

Why it matters

The older model, trust anything already inside the network perimeter, fails the moment an attacker gets past the perimeter once, through a phished credential or a compromised device, since everything inside is then implicitly trusted. Zero trust removes that single point of failure by requiring verification at every step, not just at the door. It also matters for remote and hybrid work specifically, where 'inside the network' no longer means a defined office perimeter at all, making the old trust model structurally unworkable rather than just outdated. It also reduces the blast radius of a supply-chain compromise, where a trusted third-party tool or library is the actual point of entry rather than a direct attack on the perimeter itself.

What goes wrong when it's handled badly

A system that calls itself zero trust but still grants broad access once a session is authenticated has not actually implemented the model, just renamed a perimeter. A concrete failure looks like a compromised employee laptop with a valid login being able to reach every internal system, rather than only the specific systems that employee's role actually requires. A concrete example is a former contractor's VPN credentials, never revoked after the contract ended, still granting broad internal network access months later, a failure zero trust's continuous verification is specifically designed to prevent. Implementing it typically means combining strong identity verification, device health checks and narrowly scoped access together, rather than any single control on its own being enough to call a system zero trust. Combining these controls, rather than adopting one in isolation, is what actually closes the gap a renamed perimeter leaves open.