The rise of cloud computing, mobile devices, the Internet of Things (IoT), and bring-your-own-device (BYOD) policies is transforming the technological landscape of contemporary enterprises.

Traditional security architectures depend on virtual private networks (VPNs) and network firewalls for protection. However, these measures fall short in defending organizations against advanced cyber threats. While such architectures limit access to company resources and services, they are inadequate for employees who require access to applications and resources across network boundaries.

As organizations transitioned to the cloud and threats evolved, Microsoft embraced a zero-trust security model.

Zero trust is founded on the principle of verified trust—trust must be established through verification before it is granted. This approach eliminates the inherent trust commonly found in legacy networks. A zero trust architecture minimizes risk across all environments by:

• Setting up strong authentication
• Verifying device compliance prior to granting access
• Enforcing least-privilege access by permitting only explicitly approved resources

Zero trust mandates the verification of all transactions between systems, encompassing user identity, network, applications, and devices. The system must authenticate each transaction and confirm its trustworthiness before permitting it to proceed. Ideally, a zero trust environment should encompass the following elements:

• Multi-Factor Authentication (MFA): Implement this mechanism to validate and secure identities. It can eliminate password expirations and potentially eliminate the need for passwords altogether. Additionally, consider using biometrics to establish strong authentication for user-backed identities.
• Device Health Validation: Assess the health of all device types. Ensure that all operating systems meet the minimum required health standards before granting access to Microsoft resources.
• Pervasive Data and Telemetry: Leverage this information to gain insight into your current security posture, evaluate the impact of new controls, correlate data across services and applications, and identify coverage gaps.
• Least Privilege Access: Adopt this approach to restrict access to only the essential resources (applications, infrastructure, and services) necessary for job functions. Avoid using access solutions that are scoped to specific resources or that grant broad access without proper segmentation.

The diagram above depicts a simplified reference architecture for Microsoft's zero trust approach. The key components in this process are:

• Microsoft Intune: Facilitates device management and allows for the application of device security policy configurations. Intune can also assist in deploying agents and creating policies for Microsoft Defender for Endpoint.
• Azure Active Directory (Azure AD): Utilizes its user and device inventory features to enable the establishment of conditional access, which verifies device health.

Intune assists in enforcing device configuration requirements on your managed devices. Subsequently, a managed device produces a health statement, which is stored in Azure AD. When a user’s device seeks access to a Microsoft resource, Azure AD begins an authentication exchange process to verify the device's health status.