Cis Azure Foundations 5.1.2

Ensure 'multifactor authentication' is 'enabled' for all users

Description

[IMPORTANT - Please read the section overview: If your organization pays for Microsoft Entra ID licensing (included in Microsoft 365 E3, E5, F5, or Business Premium, and EM&S E3 or E5 licenses) and CAN use Conditional Access, ignore the recommendations in this section and proceed to the Conditional Access section.]

Enable multifactor authentication for all users.

Note: Since 2024, Azure has been rolling out mandatory multifactor authentication. For more information:

• https://azure.microsoft.com/en-us/blog/announcing-mandatory-multi-factor-authentication-for-azure-sign-in
• https://learn.microsoft.com/en-us/entra/identity/authentication/concept-mandatory-multifactor-authentication

Rationale

Multifactor authentication requires an individual to present a minimum of two separate forms of authentication before access is granted. Multifactor authentication provides additional assurance that the individual attempting to gain access is who they claim to be. With multifactor authentication, an attacker would need to compromise at least two different authentication mechanisms, increasing the difficulty of compromise and thus reducing the risk.

Impact

Users would require two forms of authentication before any access is granted. Additional administrative time will be required for managing dual forms of authentication when enabling multifactor authentication.

Audit Procedure

Using Azure Portal

1. Go to Microsoft Entra ID.
2. Under Manage, click Users.
3. Click Per-user MFA from the top menu.
4. Ensure that Status is enabled for all users.

Using PowerShell

get-mguser -All | where {$_.StrongAuthenticationMethods.Count -eq 0} | Select-Object -Property UserPrincipalName

If the output contains any UserPrincipalName, then this recommendation is non-compliant.

Expected Result

All users should have MFA enabled. The PowerShell command should return no results (no users without strong authentication methods).

Remediation

Remediate from Azure Portal

1. Go to Microsoft Entra ID.
2. Under Manage, click Users.
3. Click Per-user MFA from the top menu.
4. Click the box next to a user with Status disabled.
5. Click Enable MFA.
6. Click Enable.
7. Repeat steps 1-6 for each user requiring remediation.

Default Value

Multifactor authentication is not enabled for all users by default. Starting in 2024, multifactor authentication is enabled for administrative accounts by default.

References

1. https://learn.microsoft.com/en-us/entra/identity/authentication/concept-mfa-howitworks
2. https://learn.microsoft.com/en-us/entra/identity/authentication/concept-mandatory-multifactor-authentication
3. https://azure.microsoft.com/en-us/blog/announcing-mandatory-multi-factor-authentication-for-azure-sign-in/
4. https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-identity-management#im-4-authenticate-server-and-services

CIS Controls

Profile

Level 1 | Automated