Azure Active Directory (Azure AD) Conditional Access is a powerful tool for enforcing access policies based on real-time conditions. It allows you to grant access to your organization's resources only when the access request meets your specified requirements. This post explores several practical scenarios where Conditional Access can significantly enhance your security posture.
Why Conditional Access?
In today's hybrid work environment, security needs to be adaptive. Relying solely on identity and password is no longer sufficient. Conditional Access acts as the intelligence layer, enabling you to:
- Grant access based on user, location, device, application, and real-time risk.
- Enforce granular controls like multi-factor authentication (MFA), session limits, and app controls.
- Reduce friction for legitimate users while blocking potentially malicious access attempts.
Common Conditional Access Scenarios
Scenario 1: Requiring MFA for All Users
This is a foundational security measure. Ensuring all users authenticate with MFA significantly reduces the risk of compromised credentials.
Conditions:
- Users: All users
- Cloud apps or actions: All cloud apps
Access Controls:
- Grant: Grant access
- Require: Require multi-factor authentication
Scenario 2: Requiring Compliant Devices for Sensitive Applications
Protect sensitive data by ensuring that only devices meeting your organization's compliance standards can access them.
Conditions:
- Users: Specific users or groups (e.g., Finance Department)
- Cloud apps or actions: Sensitive applications (e.g., Financial Management App)
- Device platforms: All platforms
- Filter for devices: Devices that are Hybrid Azure AD joined or Azure AD joined AND marked as compliant
Access Controls:
- Grant: Grant access
- Require: Require device to be marked as compliant
Scenario 3: Blocking Access from Untrusted Locations
Prevent unauthorized access by blocking sign-ins from specific geographic locations or known untrusted IP address ranges.
Conditions:
- Users: All users
- Cloud apps or actions: All cloud apps
- Locations: Any location (excluding trusted locations)
Access Controls:
- Grant: Block access
Note: You'll need to define your trusted locations (e.g., your corporate network IP ranges) in Azure AD.
Scenario 4: Enforcing MFA for Guest Users
Strengthen security for external collaborators by requiring MFA when they access your resources.
Conditions:
- Users: Guest users (External users)
- Cloud apps or actions: All cloud apps
Access Controls:
- Grant: Grant access
- Require: Require multi-factor authentication
Scenario 5: Limiting Session Length for Browsers
Enhance security by periodically prompting users to sign in again when accessing resources via web browsers.
Conditions:
- Users: All users
- Cloud apps or actions: Specific applications where session control is critical
- Client apps: Browser
Access Controls:
- Grant: Grant access
- Session: Sign out after a specified interval (e.g., 12 hours)
Implementing Conditional Access
To implement these policies:
- Navigate to the Azure portal and select Azure Active Directory.
- Go to Security > Conditional Access.
- Click on + New policy to create a new policy.
- Configure the assignments (users, apps, conditions) and access controls as per the scenarios described above.
- Crucially, start by using the Report-only mode to test your policies without enforcing them. This helps prevent accidental lockouts. Once confident, switch to On.
Conclusion
Azure AD Conditional Access is a cornerstone of modern cloud security. By thoughtfully implementing policies tailored to your organization's needs, you can create a robust defense-in-depth strategy that adapts to evolving threats and user behaviors. Experiment with different scenarios in report-only mode to find the optimal balance between security and user experience.