Plan Hybrid Identity Design Decisions

This document outlines the key design decisions to consider when planning your hybrid identity solution with Azure Active Directory (Azure AD). A well-thought-out design ensures security, scalability, and a seamless user experience.

1. Identity Synchronization Strategy

Choose how you will synchronize identities between your on-premises Active Directory and Azure AD.

  • Azure AD Connect (Express Settings): Suitable for simple, single-forest environments.
  • Azure AD Connect (Custom Settings): Provides more control over synchronization rules, OU filtering, and attribute selection. Essential for multi-forest scenarios or specific attribute requirements.
  • Password Hash Synchronization (PHS): Synchronizes a hash of the user's on-premises password hash to Azure AD. Simplest authentication method for hybrid.
  • Pass-through Authentication (PTA): Users authenticate directly against your on-premises AD. Requires agents on-premises.
  • Federation (AD FS or other IdP): Users authenticate against an on-premises Identity Provider. Most complex, but offers maximum control and supports advanced scenarios.

Decision Point: Evaluate the complexity of your on-premises AD infrastructure, security requirements, and the desired authentication experience for users.

2. Authentication Method

Decide on the primary method users will employ to authenticate to cloud resources.

  • Password Hash Synchronization (PHS): Recommended for most scenarios due to its simplicity and resilience.
  • Pass-through Authentication (PTA): Good for organizations that cannot allow password hashes to be stored in the cloud or require immediate enforcement of on-premises password policies.
  • Federation: If you have existing complex federation infrastructure or specific compliance needs that dictate it.

Decision Point: Consider the trade-offs between simplicity, security posture, and control over the authentication process.

3. Device Management Strategy

Determine how devices will be managed and joined to your hybrid environment.

  • Hybrid Azure AD Joined Devices: Devices are joined to your on-premises AD and registered with Azure AD. Enables single sign-on to both on-premises and cloud resources.
  • Azure AD Joined Devices: Devices are joined directly to Azure AD. Ideal for cloud-only or remote-first organizations.
  • Azure AD Registered Devices: Devices are registered with Azure AD, typically BYOD scenarios, allowing access to company resources while keeping personal data separate.

Decision Point: Align with your organization's mobility policies, security requirements, and user device ownership models.

4. Access Control and Conditional Access Policies

Plan how you will enforce access policies based on user, location, device, and application.

  • Conditional Access Policies: Define granular access controls based on conditions such as user group, sign-in risk, device state, and application.
  • Multi-Factor Authentication (MFA): Implement MFA for all users, especially administrators and access to sensitive applications.
  • Location-Based Access: Restrict access from untrusted locations.
  • Device Compliance: Enforce access only from compliant and managed devices.

Decision Point: Prioritize security for critical applications and sensitive data. Define clear policies for different user roles and scenarios.

5. User Provisioning and De-provisioning

Establish a clear process for managing user lifecycles.

  • Automated Provisioning: Leverage Azure AD Connect for initial user creation and synchronization.
  • Lifecycle Management: Define workflows for user onboarding, offboarding, and role changes, ensuring timely updates in both on-premises AD and Azure AD.
  • JIT (Just-In-Time) Access: Consider JIT access for privileged roles to minimize the attack surface.

Decision Point: Ensure that user accounts are created, updated, and deleted promptly and accurately across all identity stores.

6. Application Integration

Plan how your existing and new applications will integrate with Azure AD for single sign-on (SSO).

  • SAML/OAuth 2.0/OpenID Connect: Integrate modern applications using standard protocols.
  • Application Proxy: Provide secure remote access to on-premises web applications without requiring a VPN.
  • Directory Synchronization for Applications: Ensure user and group information is available to applications that rely on directory data.

Decision Point: Inventory all applications, assess their authentication methods, and prioritize integration based on business impact and security needs.

7. Identity Protection and Monitoring

Implement measures to detect, investigate, and respond to identity-related threats.

  • Azure AD Identity Protection: Utilize risk-based policies, anomaly detection, and automated remediation.
  • Azure AD Sign-in Logs: Regularly review sign-in logs for suspicious activity.
  • Azure Sentinel: Integrate Azure AD logs with a SIEM solution for advanced threat hunting and incident response.

Decision Point: Define your security monitoring strategy and the processes for responding to security alerts.

8. Disaster Recovery and High Availability

Ensure business continuity for your hybrid identity services.

  • Azure AD Connect High Availability: Configure staging mode for Azure AD Connect to facilitate failover.
  • Pass-through Authentication Agents: Deploy multiple agents across different servers and locations.
  • Federation Server Redundancy: Ensure your on-premises federation infrastructure is highly available.

Decision Point: Understand the critical components of your hybrid identity solution and design for resilience.

By carefully considering these design decisions, you can build a robust, secure, and efficient hybrid identity solution that empowers your users and protects your organization.