Zero Trust Architecture: Never Trust, Always Verify

Traditional security was like a castle: Hard outer wall (Firewall/VPN), soft inside. Once an attacker breached the VPN, they could move laterally to any server, database, or file share because "inside" meant "trusted."

The Core Principles of Zero Trust

1. Verify Explicitly: Never trust a user just because they are on the office Wi-Fi. Authenticate and authorize every single request based on identity, location, device health, and anomaly detection.
2. Use Least Privilege Access: Give users access ONLY to the specific application they need, for the specific time they need it (Just-In-Time access). A marketing intern should not have network access to the production database.
3. Assume Breach: Design the network as if an attacker is already present. Encrypt all internal traffic (mTLS). Segment the network so a breach in one zone doesn't spill over to another.

Implementation: Moving Beyond VPNs

Modern "Zero Trust Network Access" (ZTNA) tools like Cloudflare Access or Google BeyondCorp replace the VPN. Users login via a web portal (SSO), get verified, and access specific apps without ever actually joining the network layer.

Key Takeaway

Zero Trust is not a product; it's a strategy. It acknowledges that the perimeter has dissolved. By verifying every request, regardless of where it comes from, you limit the blast radius of any potential compromise.