Security7 min read

Zero Trust Architecture

Design systems where no user, device, or service is trusted by default. Verify explicitly, use least privilege, and assume breach at every layer.

zero-trustsecurityidentitynetwork-security

Zero Trust is a security model that eliminates implicit trust-even within the perimeter. Every request must be authenticated, authorized, and continuously validated. It's a strategic shift from "trust but verify" to "never trust, always verify."

Treat every network location, user, and device as hostile. Authenticate and authorize every request. Grant minimal permissions just-in-time. Log everything. Assume you are already compromised and design accordingly.

Workflow

Enforce strong identity for all principalsIdentity is the new perimeter-all access decisions start here.
Apply least-privilege access controlOver-provisioned accounts amplify blast radius of any compromise.
Microsegment networks and servicesFlat networks let attackers move laterally unchecked once inside.
Validate device health postureCompromised or unpatched devices can bypass user-level auth controls.
Monitor, detect, and respond continuouslyZero trust assumes breach-continuous monitoring catches attacks mid-flight.

Output Format

Identity-verified access with MFA, least-privilege ABAC policies, microsegmented network with allow-lists, device posture checks, centralized audit logging.

Examples

SPIFFE workload identity: services get X.509 SVIDs from SPIRE; no shared secrets or passwords

Istio authorization policy: `action: DENY; source: notPrincipals: ["cluster.local/ns/payments/sa/payment-service"]`

JIT access: request elevated role via PAM, auto-expire after 2 hours, require justification ticket

Edge Cases & Gotchas

Legacy apps that cannot support modern auth require wrapping with a reverse proxy that enforces identity (BeyondCorp Enterprise, Cloudflare Access)
Service mesh mTLS adds latency-measure P99 before enforcing strict mode in high-throughput paths
JIT access tools require on-call engineers to pre-provision access paths before incidents to avoid slowdown during response

When to Break These Rules

Small internal tools with no sensitive data and no external attack surface can use simpler VPN-based access-zero trust adds operational overhead worth paying for sensitive systems.

Reference Files

NIST SP 800-207 Zero Trust: https://doi.org/10.6028/NIST.SP.800-207
Google BeyondCorp: https://cloud.google.com/beyondcorp
SPIFFE/SPIRE: https://spiffe.io/
Cloudflare Zero Trust: https://www.cloudflare.com/zero-trust/