Zero Trust Architecture: Implementation Guide // WITG

Zero trust isn’t a product you buy. It’s a framework you implement. Here’s how to actually do it in a mid-size environment without losing your mind.

The Core Principle

Never trust, always verify. Every request — whether it comes from inside or outside your network — must be authenticated, authorized, and continuously validated.

Step 1: Identity Foundation

Before anything else, lock down your identity infrastructure:

Deploy conditional access policies in your identity provider
Enforce MFA everywhere — no exceptions
Implement just-in-time (JIT) access for privileged accounts
Set up continuous session evaluation

Step 2: Network Segmentation

Break up your flat network:

# Example: Azure NSG rules for microsegmentation
az network nsg rule create \
  --resource-group prod-rg \
  --nsg-name web-tier-nsg \
  --name allow-app-tier \
  --priority 100 \
  --source-address-prefixes 10.0.2.0/24 \
  --destination-port-ranges 443 \
  --access Allow

Step 3: Device Trust

Every device accessing your resources needs to prove it’s compliant:

Endpoint detection and response (EDR) on all devices
Device compliance policies enforced before access
Certificate-based authentication for managed devices

Step 4: Application Access

Move away from VPNs toward application-specific access:

Deploy a zero trust network access (ZTNA) solution
Configure per-application access policies
Enable continuous posture assessment

The Bottom Line

Zero trust is a journey, not a destination. Start with identity, expand to network, and keep iterating. The goal isn’t perfection — it’s continuous improvement of your security posture.