Description:

Microsoft Admin Portals (such as Azure Admin Portal, Microsoft 365 Admin Center, and other Microsoft service admin interfaces) provide privileged access to sensitive and critical administrative functions for services within the Microsoft Entra ID (Azure AD) ecosystem. To protect these portals from unauthorized access and mitigate the risk of credential theft or misuse, it is essential to require Multi-Factor Authentication (MFA) for all users accessing them.

Enforcing MFA for admin portals ensures that even if an administrator’s password is compromised, the attacker would still need access to a second factor (e.g., a mobile device, hardware token, or biometrics) to gain access. This significantly improves the security posture of your organization.

Rationale:

Requiring MFA for accessing Microsoft Admin Portals helps to:

  • Enhance security by ensuring that administrators access critical systems only after successfully authenticating with a second factor.

  • Prevent unauthorized access to sensitive administrative functions by adding an additional authentication layer.

  • Meet compliance requirements in organizations or industries that mandate strong authentication mechanisms for access to administrative systems.

  • Ensure accountability by linking access to admin portals with verifiable multi-factor authentication events.

Impact:

Enforcing MFA on Microsoft Admin Portals will:

  • Improve security for your organization's admin functions.

  • Add an additional step for admins to access these portals, slightly increasing the time it takes to log in, but significantly improving security.

  • Help comply with industry standards, regulations, and best practices for secure authentication to privileged portals.

Default Value:

By default, Microsoft Admin Portals do not require MFA for access. This setting needs to be manually configured to enforce MFA for users accessing these portals.

Pre-requisites:

  • Azure subscription with Microsoft Entra ID (Azure AD) configured.

  • Global Administrator or Security Administrator role permissions to configure MFA for admin portals.

  • Azure AD Multi-Factor Authentication (MFA) enabled for all users who need access to admin portals.

Audit:

  1. Sign in to Azure portal as a Global Administrator or Security Administrator.

  2. Navigate to Azure Active Directory > Security > Conditional Access to review the policies enforcing MFA.

  3. Ensure that MFA is required for access to Microsoft Admin Portals such as Microsoft 365 Admin Center and Azure Admin Portal.

Implementation Steps (Manual):

  1. Sign in to Azure portal:

    • Use an account with Global Administrator or Security Administrator permissions.

  2. Navigate to Microsoft Entra ID (Azure AD):

    • In the Azure portal, go to Azure Active Directory.

  3. Go to Conditional Access:

    • Under Security, select Conditional Access.

  4. Create a New Conditional Access Policy:

    • In Conditional Access, click + New policy to create a new policy.

  5. Define the Policy Conditions:

    • Under Assignments, select Users and groups. Choose the users or groups that should be required to use MFA to access the admin portals (typically, select all administrators).

    • Under Cloud apps or actions, select All cloud apps or specifically the admin portals you want to enforce MFA for, such as Microsoft 365 Admin Center and Azure Admin Portal.

  6. Set the Grant Control to Require MFA:

    • Under the Grant section, select Require multi-factor authentication. This will enforce MFA when accessing any of the admin portals defined.

  7. Review and Create:

    • Review your Conditional Access policy and ensure it is correctly set up to require MFA for admin portal access.

    • Click Create to enable the policy.

  8. Verify MFA Enforcement for Admin Portal Access:

    • After the policy is created, test the configuration by attempting to log in to the Azure Admin Portal or Microsoft 365 Admin Center.

    • Ensure that MFA is required for logging in.

  9. Monitor Sign-in Attempts:

    • Use Azure AD Sign-in logs to monitor and verify that MFA is being enforced for users accessing the admin portals.

Example Sign-in logs query in Log Analytics:

SigninLogs

| where ConditionalAccessStatus == "failure"

| where ActivityDisplayName == "Microsoft Admin Portal"

| take 10

  1. Automate MFA Enforcement via PowerShell (Optional): You can automate the enforcement of MFA for admin portals using PowerShell by creating a Conditional Access policy through the PowerShell interface.

Example command to create a Conditional Access policy:

New-AzureADMSConditionalAccessPolicy -DisplayName "Require MFA for Admin Portals" -State "enabled" -Conditions @{

    Users=@{Include="All Administrators"}

    Applications=@{Include="All"} 

} -GrantControls @{

    BuiltInControls="Mfa"

}

  1. Set Up Alerts for MFA Failures (Optional):

    • You can create alerts in Azure Monitor to notify administrators of MFA failures when users attempt to access the admin portals.

    • In Azure Monitor, go to Alerts and create a new alert rule based on Sign-in logs and Conditional Access failure events.

Backout Plan (Manual):

  1. Sign in to Azure portal:

    • Use an account with Global Administrator or Security Administrator permissions.

  2. Navigate to Microsoft Entra ID (Azure AD):

    • Go to Azure Active Directory in the Azure portal.

  3. Disable or Modify the Conditional Access Policy:

    • In Conditional Access, find the policy that requires MFA for admin portal access.

    • Either delete the policy or disable the MFA requirement for admin portal access.

  4. Verify the Change:

    • After disabling or deleting the policy, test logging into the Microsoft Admin Portals (e.g., Microsoft 365 Admin Center and Azure Admin Portal) to confirm that MFA is no longer required.

  5. Test the Reverted Configuration:

    • Log in to the admin portals using a user account and verify that MFA is no longer enforced.

References: