Zero Trust

Cloud-based services and mobile computing have changed the technology landscape for the modern enterprise. Today’s workforce often requires access to applications and resources outside traditional corporate network boundaries, rendering security architectures that rely on firewalls and virtual private networks (VPNs) insufficient. Changes brought about by cloud migration and a more mobile workforce has led to the development of an access architecture called Zero Trust.

The Zero Trust model

Based on the principle of “never trust, always verify,” Zero Trust helps secure corporate resources by eliminating unknown and unmanaged devices and limiting lateral movement. Implementing a true Zero Trust model requires that all components—user identity, device, network, and applications—be validated and proven trustworthy. Zero Trust verifies identity and device health prior to granting access to corporate resources. When access is granted, applying the principle of least privilege limits user access to only those resources that are explicitly authorized for each user, thus reducing the risk of lateral movement within the environment. In an ideal Zero Trust environment, the following four elements are necessary:

  • Strong identity authentication everywhere (user verification via authentication)

  • Devices are enrolled in device management, and their health is validated

  • Least-privilege user rights (access is limited to only what is needed)

  • The health of services is verified (future goal)

For Microsoft, Zero Trust establishes a strict boundary around corporate and customer data. For end users, Zero Trust delivers a simplified user experience that allows them to easily manage and find their content. And for customers, Zero Trust creates a unified access platform that they can use to enhance the overall security of their entire ecosystem.

Zero Trust architecture

A Zero Trust approach extends throughout the entire digital estate and serves as an integrated security philosophy and end-to-end strategy.

The illustration below provides a representation of the primary elements that contribute to Zero Trust.

In the illustration above:

Security policy enforcement is at the center of a Zero Trust architecture. This includes Multi-Factor authentication with conditional access that takes into account user account risk, device status, and other criteria and policies that you set.

Identities, devices (also called endpoints), data, applications, network, and other infrastructure components are all configured with appropriate security. Policies that are configured for each of these components are coordinated with your overall Zero Trust strategy. For example, device policies determine the criteria for healthy devices and conditional access policies require healthy devices for access to specific apps and data.

Threat protection and intelligence monitors the environment, surfaces current risks, and takes automated action to remediate attacks.

Guiding principles of Zero Trust

Today, organizations need a new security model that effectively adapts to the complexity of the modern environment, embraces the mobile workforce, and protects people, devices, applications, and data wherever they are located.

To address this new world of computing, Microsoft highly recommends the Zero Trust security model, which is based on these guiding principles:

  • Verify explicitly - Always authenticate and authorize based on all available data points.

  • Use least privilege access - Limit user access with Just-In-Time and Just-Enough-Access (JIT/JEA), risk-based adaptive policies, and data protection.

  • Assume breach - Minimize blast radius and segment access. Verify end-to-end encryption and use analytics to get visibility, drive threat detection, and improve defenses.

Microsoft's Zero Trust architecture

Below is a simplified reference architecture for our approach to implementing Zero Trust. The primary components of this process are Intune for device management and device security policy configuration, Azure AD conditional access for device health validation, and Azure AD for user and device inventory.

The system works with Intune, pushing device configuration requirements to the managed devices. The device then generates a statement of health, which is stored in Azure AD. When the device user requests access to a resource, the device health state is verified as part of the authentication exchange with Azure AD.


The National Institute of Standards and Technology has a Zero Trust Architecture, NIST 800-207, publication.

Microsoft Identity Manager or MIM helps organizations manage the users, credentials, policies, and access within their organizations and hybrid environments. With MIM, organizations can simplify identity lifecycle management with automated workflows, business rules, and easy integration with heterogenous platforms across the datacenter. MIM enables Active Directory Domain Services to have the right users and access rights for on-premises apps. Azure AD Connect can then make those users and permissions available in Azure AD for Microsoft 365 and cloud-hosted apps.

On-premises Active Directory Domain Services, Azure Active Directory (Azure AD), or a hybrid combination of the two all offer services for user and device authentication, identity and role management, and provisioning.

Identity has become the common factor among many services, like Microsoft 365 and Xbox Live, where the person is the center of the services. Identity is now the security boundary, the new firewall, the control plane—whichever comparison you prefer. Your digital identity is the combination of who you are and what you’re allowed to do. That is:

Credentials + privileges = digital identity

First step, you need to help protect your privileged accounts.

These identities have more than the normal user rights and, if compromised, allow a malicious hacker to access sensitive corporate assets. Helping secure these privileged identities is a critical step to establishing security assurances for business assets in a modern organization. Cybercriminals target these accounts and other privileged services in their kill chain to carry out their objectives.

Evolution of identities

Identity management approaches have evolved from traditional, to advanced, to optimal.

Traditional identity approaches

  • On-premises identity providers.

  • No single sign-on is present between on-premises and cloud apps.

  • Visibility into identity risk is very limited.

Advanced identity approaches

  • Conditional access policies gate access and provide remediation actions.

  • Analytics improve visibility into identity risk.

Optimal identity approaches

  • Passwordless authentication is enabled.

  • User, location, devices, and behavior are analyzed in real time.

  • Continuous protection to identity risk.

Steps for a passwordless world

  • Enforce MFA — Conform to the fast identity online (FIDO) 2.0 standard, so you can require a PIN and a biometric for authentication rather than a password. Windows Hello is one good example, but choose the MFA method that works for your organization.

  • Reduce legacy authentication workflows — Place apps that require passwords into a separate user access portal and migrate users to modern authentication flows most of the time. At Microsoft only 10 percent of our users enter a password on a given day.

  • Remove passwords — Create consistency across Active Directory Domain Services and Azure Active Directory (Azure AD) to enable administrators to remove passwords from identity directory.


We recommend Azure AD Privileged Identity Management as the service to help protect your privileged accounts.

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