# Zero Trust Model > Chapter 136 of the Courseiva AZ-900 curriculum — https://courseiva.com/learn/az-900/zero-trust-model **Official objective:** 2.5 — Describe identity, access, and security ## Introduction This chapter covers Zero Trust, a security model referenced throughout Azure's security guidance. AZ-900 tests this under objective 2.5, as a foundational security concept underlying many Azure security features covered elsewhere in this guide. ## Checking ID Every Time, Not Just at the Front Door A traditional office building checks your ID once at the front door, and after that, you can walk freely to any floor or room. A more cautious building checks your ID again at every sensitive door you try to open — not because it distrusts you personally, but because it doesn't assume that getting past the front door means you should be trusted everywhere inside. The Zero Trust security model applies that same idea to technology: instead of assuming anything inside a network is automatically trustworthy just because it got past the initial perimeter, every request is verified on its own merits. ## Core explanation ### What Zero Trust means Zero Trust is a security model based on the principle "never trust, always verify." Rather than assuming a user or device is trustworthy simply because it's inside a traditional network perimeter, Zero Trust verifies every access request explicitly, based on available signals, regardless of where the request originates. ### Core principles Zero Trust is commonly described around a few guiding principles: **verify explicitly** (authenticate and authorize based on all available signals, not just network location), **use least-privilege access** (grant only the access actually needed, connecting to the RBAC concepts covered in an earlier chapter), and **assume breach** (design systems as if an attacker may already have some level of access, minimizing the damage any single compromised credential or device can cause). ### Why this shift matters Traditional security models often relied heavily on a strong network perimeter — trusting anything "inside" the corporate network. As work has become more distributed (remote work, cloud services, personal devices), that perimeter-based trust model became less reliable. Zero Trust doesn't depend on a strong perimeter; it verifies continuously regardless of location. ### How Zero Trust connects to other Azure security features Many Azure identity and security features covered elsewhere in this guide put Zero Trust principles into practice — Conditional Access (verifying based on signals like device and location), multi-factor authentication (verifying more than one factor rather than trusting a single credential), and RBAC (least-privilege access) all reflect Zero Trust thinking. ## Real-world context An organization adopting Zero Trust principles requires multi-factor authentication and device compliance checks for accessing sensitive resources, regardless of whether the request comes from inside the corporate office or a remote location — trust is based on verified signals, not network location alone. ## Exam focus Objective 2.5 expects a conceptual understanding of Zero Trust as a "never trust, always verify" security model, and recognition of its core principles. A common wrong answer is describing Zero Trust as simply "extra strict network firewalls" — it's a broader philosophy about verifying every request explicitly, regardless of network location, not just a stronger perimeter. Stable terms: **Zero Trust**, **verify explicitly**, **least-privilege access**, **assume breach**. Memory trick: Zero Trust = never trust based on location alone; always verify explicitly, every time. ## Step by step 1. **Verify explicitly for every request** — Authentication and authorization decisions are based on all available signals, not simply on whether a request originates from inside a trusted network. 2. **Apply least-privilege access** — Users and systems are granted only the access they actually need, minimizing what a compromised account could reach. 3. **Design as if breach is possible** — Systems are designed to limit the damage a compromised credential or device could cause, rather than assuming perimeter security alone is sufficient. ## Common misconceptions - **Misconception:** Zero Trust just means having a very strict network firewall. **Reality:** Zero Trust is a broader philosophy about verifying every access request explicitly based on available signals, rather than trusting anything simply because it's inside a network perimeter. - **Misconception:** Zero Trust means literally trusting no one, ever, for anything. **Reality:** It means not extending automatic trust based on network location alone — access is still granted, but based on explicit verification rather than assumed trust. ## Key takeaways - Zero Trust is a security model based on 'never trust, always verify,' rather than assuming trust based on network location. - Core principles include verifying explicitly, using least-privilege access, and assuming breach is possible. - Many Azure security features (Conditional Access, MFA, RBAC) put Zero Trust principles into practice. ## FAQ **What is the Zero Trust model?** It's a security model based on the principle 'never trust, always verify' — rather than assuming a user or device is trustworthy because it's inside a traditional network perimeter, every access request is verified explicitly based on available signals. **How does Zero Trust relate to features like MFA and RBAC?** Multi-factor authentication, Conditional Access, and RBAC all put Zero Trust principles into practice — verifying explicitly and granting least-privilege access, rather than relying on network-location-based trust alone. --- Interactive version with quiz and diagrams: https://courseiva.com/learn/az-900/zero-trust-model