Setting up a specific list of users in Microsoft SharePoint 365 to
enforce Two-Factor Authentication (2FA) via the Microsoft Authenticator App involves configuring
Conditional Access Policies in
Azure Active Directory (Azure AD). This method ensures that the selected users must use multi-factor authentication (MFA) when accessing SharePoint and other services. Below are the detailed steps to set this up:
Step 1: Confirm License Requirements
- Ensure that your Microsoft 365 tenant includes the necessary Azure AD Premium P1 or P2 licenses since Conditional Access is a feature of these plans.
- Check the license assignments for the specific users needing 2FA.
Step 2: Enable Multi-Factor Authentication (MFA) for the Selected Users
- Login to Microsoft 365 Admin Center:
- Go to https://admin.microsoft.com and log in using your Global Admin account.
- Access Active Users:
- Navigate to Users > Active Users.
- Enable MFA:
- Select the users that require 2FA.
- In the toolbar, choose Multi-Factor Authentication Setup.
- Enable MFA for the selected users; this ensures that 2FA prompts will occur when accessing Microsoft 365.
Step 3: Create a Conditional Access Policy to Enforce MFA for SharePoint
To enforce specific policies for SharePoint only:
- Login to Azure AD:
- Go to the Azure portal at https://aad.portal.azure.com and log in with an account that has global admin or security admin permissions.
- Open Conditional Access:
- In Azure AD, navigate to Security > Conditional Access.
- Create a New Policy:
- Click + New policy and give it a descriptive name, e.g., "Require MFA for SharePoint."
- Select Users:
- Under Assignments, go to Users or workload identities.
- Select the option Users and groups, and then specify the users or groups requiring 2FA.
- Select Cloud Apps:
- Under Cloud apps or actions, click Include and choose Select apps.
- In the app selection menu, search for and select SharePoint Online.
- Set Conditions (Optional):
- If you'd like to specify conditions such as device platform, location, or client app, define these under the Conditions section.
- Set Grant Controls:
- Under Grant, select:
- Require multi-factor authentication.
- Click Select to apply the grant control.
- Enable the Policy:
- Set the policy to Report-only mode first to monitor its effect without enforcing it immediately.
- After testing, switch the policy to On to enforce it.
Step 4: Test the Conditional Access Policy
- Ask one of the affected users to log in to SharePoint Online and verify they receive a 2FA prompt via the Microsoft Authenticator App.
- Address any unexpected issues during the testing phase.
Step 5: Monitor and Manage the Policy
- Monitor the policy’s effectiveness via Azure AD logs:
- Navigate to Sign-ins in Azure AD to review the authentication logs.
- If issues arise, refine the Conditional Access policy settings or exclusion criteria.
Additional Notes:
- Remember Backup Options:
- Ensure users have backup methods configured (such as a phone number for SMS).
- Train users on how to use the Authenticator App, including app setup, receiving verification codes, or approving push notifications.
- Exclusions:
- You may need to exclude certain service or admin accounts from the policy to avoid lockout scenarios.
By following these steps, you can enforce multi-factor authentication for specific users accessing Microsoft SharePoint Online, significantly enhancing the security of your system. Let me know if you encounter any challenges during setup!