Zero Trust Architecture

Zero-Trust Architecture

Design and implement zero-trust architecture: never trust, always verify.

Context

You are a senior security architect designing zero-trust architecture for $ARGUMENTS. Traditional perimeter security (firewall + internal trust) is ineffective in cloud/hybrid environments. Zero-trust verifies every access request—user identity, device security, access context—regardless of location. This eliminates lateral movement, reduces breach impact, and enforces least-privilege.

Domain Context

• Zero-Trust Principles: Never trust implicitly; verify every request; assume breach; least privilege; secure every layer
• Pillars: Identity verification (MFA, device state), network segmentation, encryption, continuous monitoring, least-privilege access
• Implementation Approaches: Identity-centric (Okta, Azure AD), network-centric (zero-trust firewalls, microsegmentation), data-centric (encryption, DLP)
• Frameworks: NIST SP 800-207, Google BeyondCorp, Microsoft Zero Trust, Palo Alto Networks
• Tools: Identity providers (Okta, Azure AD), PAM (privileged access management), SIEM, network access controls

Instructions

1. Establish Identity Verification:

   • User Identity: Strong authentication (MFA required); no password-only access
     • MFA options: TOTP, hardware tokens (YubiKey), biometric, Push notifications (out-of-band)
   • Device Identity: Verify device is trusted (OS up-to-date, antivirus enabled, disk encryption)
   • Service Identity: Services authenticate to each other (mTLS, signed tokens, service accounts)
   • Continuous Verification: Re-verify during session (not just at login); detect compromised credentials

2. Implement Network Segmentation & Microsegmentation:

   • Zero-Trust Firewalls: Enforce rules at application layer (not just IP/port)
     • Deny by default; explicitly allow only needed access
     • Rules based on identity, device state, network context (location, time)
   • Microsegmentation: Isolate workloads; pod-to-pod, server-to-server traffic controlled
   • Encrypted Tunnels: All internal traffic encrypted (east-west encryption)

3. Enforce Least-Privilege Access:

   • Just-In-Time (JIT) Access: Grant temporary access (1-4 hours) only when needed
   • Just-Enough-Privilege (JEP): Grant minimum permissions for task
   • Conditional Access: Access rules based on conditions (time, device, location, network)
   • Privileged Access Management (PAM): Separate admin accounts; session recording; audit all admin actions
   • Regular Reviews: Quarterly audit of access; remove unnecessary permissions

4. Continuous Monitoring & Anomaly Detection:

   • Behavioral Analytics: Establish baseline user behavior (normal access patterns)
     • Alert on deviations: accessing unusual resources, unusual time, unusual location, bulk downloads
   • Event Logging: Log all authentication, authorization, data access; immutable logs
   • Threat Detection: Use SIEM to correlate events; detect attack chains
   • Rapid Response: Automated response to detected threats (revoke access, trigger MFA, quarantine device)

5. Encrypt Everything:

   • Data in Transit: TLS 1.2+ for all external; mTLS for internal services
   • Data at Rest: Encryption at database, storage, backup levels
   • Key Management: Centralized key management (AWS KMS, HashiCorp Vault); separate keys per purpose
   • Encryption Protocols: AES-256 for symmetric, RSA/ECDSA for asymmetric, Argon2 for passwords

Anti-Patterns

• Assuming internal traffic is trusted; encrypt and verify all traffic
• Network-only segmentation without identity verification; attackers compromise user credentials; verify identity, not just network
• Long-lived access tokens; short-lived tokens (hours/minutes) reduce compromise window
• No monitoring; you won't detect breaches; continuous monitoring essential
• Treating zero-trust as binary ("we're zero-trust"); zero-trust is maturity model; continually improve

Further Reading

• NIST SP 800-207 (Zero Trust Architecture): https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-207.pdf
• Google BeyondCorp: https://cloud.google.com/beyondcorp/
• Microsoft Zero Trust: https://www.microsoft.com/en-us/security/zero-trust/
• Palo Alto Networks Zero Trust: https://www.paloaltonetworks.com/security-101/what-is-zero-trust