Table of Contents
Increase MFA Usage with a Conditional Access Policy
On November 6, Alex Weinert, Microsoft’s VP for Identity Security, announced the “auto-rollout of Microsoft Entra Conditional Access policies that will automatically protect tenants based on risk signals, licensing, and usage.” The text explains that Microsoft will deploy up to three conditional access policies to “eligible tenants.” The policies require people to use multi-factor authentication (MFA) to access specific forms of data, such as Microsoft 365 admin centers.
Microsoft says that their “data tells us they [the policies] would increase an organization’s security posture.” Microsoft also points to a May 2023 study by Cornell University that finds MFA reduces the risk of account compromise by 99.22%. This is broadly in line with previous assertions about the effectiveness of MFA in stopping password spray and other attacks.
The aim of the initiative is to increase the overall usage of MFA across Microsoft from the poor levels reported over the last few years. At the TEC 2022 conference, Alex Weinert reported the figure to be 26.18% for all Microsoft 365 accounts and 34.15% for accounts holding an administrative role. Since then, Microsoft has rolled out new features to drive MFA usage and improve security, such as hardening the authenticator app, including authenticator lite in Outlook mobile, and pushing registration campaigns to encourage users to move from insecure MFA response methods to the authenticator app.
New Conditional Access Policies Deployed to Tenants
Initially, Microsoft will deploy three conditional access policies to tenants, who’ll receive a notification when the policies are present. A 90-day countdown starts after which Microsoft will automatically enable the policies. During this period, administrators can go to the Entra ID admin center (Figure 1) to review the policy settings and decide whether to tweak the policy settings.
For instance, Microsoft recommends that you exclude break glass accounts from the set of users covered by the policies to avoid encountering access problems if you need to use the break glass accounts.
Initially, the Microsoft-managed policies are in the report-only state. If administrators leave the policies alone, Microsoft will automatically enable the policies after the 90-day countdown lapses. If you don’t want Microsoft to do this, set the policy to Off. The first order of business is therefore to keep an eye on notifications posted by Microsoft and then review whatever policies appear in your tenant. Of course, there’s nothing to stop you from putting these policies into operation immediately.
Microsoft-Managed Conditional Access Policies
Table 1 lists the three initial Microsoft-managed policies. You can see that the policies focus on tenants with Microsoft Entra ID Premium licenses. That’s because these licenses are necessary to manage conditional access policies. Entra ID Premium P1 is included the Microsoft 365 E3 and Microsoft 365 Business Standard products. Entra ID Premium P2 is included in Microsoft 365 E5.
|Conditional access policy||Eligible tenants||What the policy does|
|Require multifactor authentication for admin portals||Tenants with Entra ID Premium P1 and P2 licenses where security defaults aren’t enabled.||Requires MFA when an account holding any of 14 designated administrative roles signs into a Microsoft administrator portal (like the Entra ID admin center or Microsoft 365 admin center). See this article for more information about why this policy is very useful.|
|Require multifactor authentication for per-user multifactor authentication users||Tenants with Entra ID Premium P1 and P2 licenses where security defaults aren’t enabled and there are less than 500 per-user MFA enabled/enforced users.||Requires MFA for all cloud apps.|
|Require multifactor authentication for high-risk sign-ins||Tenants with Entra ID Premium P2 licenses where there are enough P2 licenses to enable the policy for all users.||Requires MFA and reauthentication when Entra ID detects high-risk sign-ins.|
See the documentation for more details about the Microsoft-managed conditional access policies.
The Case of Per-User MFA
The fact that Microsoft has chosen to include a managed conditional access policy for per-user MFA users deserves some comment. Microsoft says that this policy “helps organizations transition to Conditional Access.” Essentially, what they’re saying is that they don’t want customers to use per-user MFA any longer. This is the form of MFA included in licenses like Office 365 E3. Administrators manage per-user MFA by selecting users and enabling MFA for them (Figure 2).
Microsoft believes that enforcing MFA through conditional access policies is a better and more robust mechanism that results in better tenant security. Administrators don’t have to worry about enabling MFA for users when creating accounts nor do they have to deal with user queries about MFA on an individual level. MFA is enforced by policy and once the policy settings work, the policy serves as many accounts as the tenant has.
Sounds good. The downside is that to move away from per-user MFA, Microsoft forces customers to purchase Entra ID Premium licenses if their base product licenses (like Microsoft 365 E3) don’t include a Microsoft Azure multi-factor authentication service plan. I think this is wrong and believe that if Microsoft really wants people to move away from per0-user MFA, they should receive free Entra ID Premium P1 licenses. That’s unlikely to happen, but it would be the right thing to do.
I support greater use of MFA within Microsoft 365. Protect yourself and protect your tenant by enabling and using MFA to protect all user accounts. You know it makes sense.