Zero Trust
2025-01-01

Overview#

Zero Trust replaces perimeter-based assumptions with continuous verification of identities, devices, and actions. Access decisions consider context (user role, device posture, location, workload identity) and enforce least privilege through policy engines and granular segmentation.

Core objectives#

  • Define a reference architecture covering identity, device health, network segmentation, and policy enforcement points.
  • Map crown-jewel applications and data flows; require strong authentication and explicit authorization for each hop.
  • Minimize implicit trust: eliminate flat networks, shared admin accounts, and long-lived credentials.
  • Instrument visibility to verify that policies are enforced and to detect anomalous behavior.

Implementation notes#

  • Start with identity: consolidate IdPs, enforce MFA/WebAuthn, and federate service-to-service auth via short-lived tokens.
  • Deploy microsegmentation or SD-WAN/overlay policies to restrict lateral movement; pair with DNS and egress controls.
  • Use device posture (managed status, patch level, EDR health) as part of access policy for high-sensitivity apps.
  • Introduce just-in-time access for administrative tasks with session recording where legal.

Operational signals#

  • Leading indicators: percentage of traffic evaluated by policy engines, MFA bypass rates, and enrollment coverage for device health signals.
  • Lagging indicators: lateral movement observed in incidents, compromised long-lived credentials, or unauthorized data egress.
  • Feedback loops: quarterly architecture reviews, control-maturity scoring, and red-team results feeding detection improvements.

Runbook essentials#

  • Onboarding new app: define resource tags, required identity assurance level, device posture rules, and network segment exposure.
  • Break-glass: time-bound emergency accounts with hardware token MFA and session logging; require post-use review.
  • Migration plan: decommission legacy VPN access as granular policies mature and user experience stabilizes.
  • Identity and access management, endpoint hardening, and secure configuration form the foundation for Zero Trust.
  • Detection engineering should monitor for policy misconfigurations, token reuse, and anomalous lateral connections.
  • Business continuity exercises should include scenarios where policy engines are degraded or unreachable.