Secure-by-Design Series: Implementing Zero Trust Architecture (ZTA)
Summary
One highly actionable Secure-by-Design topic for security engineers is implementing Zero Trust Architecture (ZTA) across enterprise networks. This model is based on the premise that no user or device, whether inside or outside the network, should be automatically trusted. Instead, access must be explicitly verified before it’s granted.
Key Concepts and Implementation Steps
1. Zero Trust Principles
- Never trust, always verify
- Assume breach and minimize lateral movement
Enforce explicit verification for all access requests
2. Identify the Protect Surface
Focus security on the most critical data, systems, or services—your "protect surface"—rather than attempting to secure the entire network. Protect surface is used here instead of attack surface because of the intentional identification of “crown jewel” or most important assets.
3. Micro-segmentation
Break your network into smaller zones with controlled access. This limits an attacker’s ability to move freely if they breach a segment.
4. Least Privilege Access
Ensure users and systems have only the access necessary for their roles, reducing the potential damage of a compromise.
5. Multifactor Authentication (MFA)
Require MFA for all access to provide an added layer of identity verification. This greatly reduces the risk of unauthorized access.
6. Continuous Monitoring and Validation
Monitor user behavior and network activity in real-time to detect anomalies. Regularly validate security configurations against policy.
7. Automation and Orchestration
Use automation to rapidly respond to threats and orchestrate complex workflows, reducing manual workload and improving response times.
8. Security Policies and Enforcement
Establish and enforce consistent security policies across on-premises, cloud, and hybrid environments. Avoid exceptions.
9. Trust Evaluation for Users and Devices
Continuously collect and analyze telemetry data to evaluate the trustworthiness of users and devices.
10. Education and Training
Train teams regularly on Zero Trust principles, tools in use, and how to recognize and respond to threats.
Key Takeaways
- Adopt a Verify-First Approach – Every access request must be verified with the assumption of a possible breach.
- Prioritize Critical Asset Protection – Identify and secure sensitive data and systems.
- Segment Your Network – Use micro-segmentation to limit attacker movement.
- Limit Privileges – Apply least privilege principles to restrict access.
- Mandate MFA – Require multifactor authentication across the organization.
Implementation Examples
Below is an example of threats, descriptions, countermeasures, and verification questions. Included with each is an example of the logic that can be used in the IriusRisk rules engine to action this content according to your strategy.
| Threat | Description | Rule Description | Countermeasure | Verification Questions |
|---|---|---|---|---|
| Unauthorized Access | Improper verification may allow unauthorized access |
Condition – Does dataflow contain Auth tag? Action – Add Threat to Destination Component |
Zero Trust Verification |
Are all access requests verified? Are just-in-time access policies in place? Is trust re-evaluated continuously? |
| Lateral Movement | Attackers may move freely in flat networks |
Condition – Dataflow crosses trust boundary Action – Add Threat to Source Component |
Network Micro-segmentation |
Is the network segmented? Are inter-segment policies enforced? Is traffic monitored? |
| Overprivileged Access | Users with too much access can cause harm |
Condition – Add Functional Component for Role Change Action – Add Risk Pattern |
Least Privilege Access Policy |
Are roles reviewed? Is access revoked promptly? Are controls dynamic? |
| Weak Authentication | Single-factor access is vulnerable |
Condition – Dataflow contains Authentication & is MFA Action – Trigger Add |
Mandatory MFA Implementation |
Is MFA enforced? Are users trained? Are logs/audits monitored? |
Conclusion
Zero Trust Architecture supports Secure-by-Design by embedding security into every layer of the system. It protects against both external and internal threats, and promotes a proactive, rigorous, and verifiable security posture for organizations.
If you are needing help implementing these things in IriusRisk or want to see how IriusRisk can help you scale your organization’s secure by design efforts, please reach out to IriusRisk today!
