Azure Active Directory (Azure AD) Conditional Access is a powerful tool for enforcing granular access controls to your cloud applications. By combining conditions, assignments, and access controls, you can implement robust security policies tailored to your organization's needs. This post outlines essential best practices to help you leverage Conditional Access effectively.
1. Start with a Baseline and Iterate
Don't try to implement all policies at once. Begin with a small set of critical policies and gradually expand. Utilize the "Report-only" mode to understand the impact of a policy before enforcing it.
2. Target High-Risk Scenarios First
Prioritize policies that address your most significant risks. Common high-risk scenarios include:
- Requiring multi-factor authentication (MFA) for all users.
- Enforcing MFA for administrators.
- Restricting access from untrusted locations.
- Requiring compliant devices for access to sensitive applications.
3. Leverage Built-in Role Assignments
When assigning policies, use Azure AD built-in roles (e.g., "Global Administrators," "User Administrators") rather than individual user accounts where possible. This simplifies management and ensures policies are applied consistently as roles change.
4. Group Applications Logically
Instead of assigning policies to individual applications, group related applications together using the "Cloud apps or actions" assignment. This reduces the number of policies you need to manage.
Example:
Create a group for all Microsoft 365 applications (e.g., Exchange Online, SharePoint Online, Teams) and apply a single policy to this group.
5. Use a Combination of Conditions
Conditional Access policies become most powerful when multiple conditions are combined. Consider using:
- Users and Groups: Target specific users or groups.
- Cloud Apps or Actions: Specify which applications or actions the policy applies to.
- Conditions:
- Device Platforms: Target specific operating systems (Windows, macOS, iOS, Android).
- Locations: Define trusted and untrusted network locations.
- Client Applications: Differentiate between browser-based access and mobile apps or desktop clients.
- Device State: Require devices to be Hybrid Azure AD joined or marked as compliant.
6. Define Granular Access Controls
Access controls are the "what" of your policy. Common controls include:
- Grant access:
- Require multi-factor authentication.
- Require device to be marked as compliant.
- Require Hybrid Azure AD joined device.
- Require approved client application.
- Require app protection policy.
- Block access: Directly deny access.
- Session controls: Apply session-specific constraints like limiting sign-in frequency or enforcing app enforced restrictions.
7. Regularly Review and Audit Policies
Security is an evolving landscape. Regularly review your Conditional Access policies to ensure they remain relevant and effective. Utilize Azure AD Sign-in logs and the Conditional Access insights and reporting workbook for auditing and troubleshooting.
8. Exclude Break-Glass Accounts
Always exclude at least two emergency access or "break-glass" accounts from your Conditional Access policies. These accounts should be highly secured and only used in emergency situations to prevent tenant lockout.
9. Understand Session Controls
Session controls offer finer-grained management of user sessions. Use them to:
- Sign-in frequency: Control how often users need to re-authenticate.
- Persistent browser session: Allow users to stay signed in after closing and reopening their browser.
- Use app enforced restrictions: Leverage controls built into specific applications (e.g., preventing downloads in SharePoint Online).
10. Educate Your Users
Communicate policy changes to your users, especially those requiring MFA or introducing new access requirements. Clear communication reduces confusion and helps users adapt to new security measures.
By implementing these best practices, you can significantly enhance your organization's security posture using Azure AD Conditional Access. Remember that security is an ongoing process, so continuous monitoring and adaptation are key.