Zero Trust Architecture

Question

What is Zero Trust Architecture and how do you implement it in a modern infrastructure?

Answer

Zero Trust is a security model that assumes no implicit trust - every request must be verified. Core principles: 1) Never trust, always verify - authenticate and authorize every access attempt. 2) Least privilege - grant minimum necessary permissions. 3) Assume breach - design as if attackers are already inside. Implementation: identity-based access (not network-based), micro-segmentation, continuous verification with MFA, device health checks, encrypted communications everywhere, comprehensive logging. Technologies: identity providers (Okta, Azure AD), service mesh (mutual TLS), BeyondCorp-style access proxies.

Why This Matters

Traditional perimeter security (castle and moat) fails in cloud-native environments with remote workers, SaaS applications, and microservices. Zero Trust shifts security to identity and per-request verification. Google's BeyondCorp pioneered this approach. Implementation is a journey - start with identity management and gradually add micro-segmentation. The goal is that compromising one system doesn't give access to everything.

Code Examples

Istio mutual TLS policy

yaml

AWS VPC micro-segmentation

hcl

Common Mistakes

Implementing Zero Trust as a product purchase instead of architectural change
Forgetting about east-west traffic (service to service) and only securing north-south
Not having comprehensive logging to detect anomalies

Follow-up Questions

Interviewers often ask these as follow-up questions

How do you handle service-to-service authentication in a Zero Trust model?
What is the role of a service mesh in Zero Trust architecture?
How do you balance Zero Trust security with developer productivity?