Understanding How App Certification for Microsoft 365 Apps Works

The Many Ways to Stress the Need for Modern Authentication

By now, all Microsoft 365 tenant administrators should be aware that Microsoft is removing support for basic authentication for many Exchange Online connectivity protocols. The aim is to complete the process by October 2022. SMTP AUTH is an exception, but Microsoft will deal with it in time.

What you might not be aware of is that access to Microsoft 365 data using modern authentication requires that the developers must register their app with Azure AD. This applies to any Microsoft API, including the Outlook add-in model and the Graph APIs. If you’ve written PowerShell scripts which make Graph queries, you know that you must register an app to receive consent for the Graph permissions necessary to access the target data. This is a basic registration. Registrations for more sophisticated apps like those sourced from ISVs contain more information about the app, such as a redirect URL for the app. Registration for ISV apps usually happens during the app installation, including the creation of a service principal to allow the app to run with API permissions consented to by tenant administrators.

Previously, I’ve written about the need for tenants to clean out application crud from Azure AD. The crud is composed of unwanted apps and their service principals accumulated over time in Azure AD. Being able to fetch sign-in data for service principals via Graph queries makes it easier to add context to this exercise by knowing what service principals are active.

After cleaning out obsolete applications, Azure AD might be tidy, but do you know much about the apps which remain? The application governance add-on for Microsoft Defender for Cloud Apps might help, but only if your tenant has the necessary licenses.

Microsoft’s App Compliance Program

Fortunately, Microsoft has an App Compliance Program, part of their Zero Trust initiative to help customers verify apps they might want to run in their tenant. App developers go through the process to achieve app certification by providing information about the app and the data it accesses. The program has three phrases or levels:

Publisher verification: The app developer has a Microsoft developer network identity. The app supports modern authentication and is capable of multi-tenant activity. This is the entry-level participation in certification.

Publisher attestation: The app developer completes a questionnaire covering security, data handling, and compliance.

Microsoft 365 certification: Instead of the app developer reporting details of their app, third-party assessors audit the assertions to validate that the app meets Microsoft standards for security and compliance. The process occurs annually, and details gathered during the audit is available online. Figure 1 shows details of a Microsoft certified app in AppSource. The audit information is available through the Microsoft 365 certification link for the app.

App certification information in AppSource
Figure 1: App certification information in AppSource

The app certification information available online (Figure 2) includes detail of the app permissions, including the reason why the app developers need administrator consent to use the permission.

App certification includes documenting API permissions
Figure 2: App certification includes documenting API permissions

Obviously, app developers must invest time and effort to satisfy Microsoft criteria for app certification. However, once completed, they should reap the benefits gained by increased customer confidence in their product. At least, that’s the theory.

Downgraded Certification

In April 2020, I reviewed the new Manage Apps section in the Teams admin center and commented on the Microsoft 365 certified status of the Wrike app. The number of apps available for Teams continues to expand (from 462 in April 2020 to 1,402 as I write this in February 2022, or roughly 44 new apps monthly). Checking the online list of Teams apps, it looks like very few apps are Microsoft 365 certified. This begs the question why app developers feel it unnecessary to go through Microsoft’s audit process – or why publishers of apps like Wrike downgraded their apps from certified to publisher attestation.

I’m sure cost has something to do with it, along with a feeling that customers don’t go looking for apps which are Microsoft 365 certified. If a developer gains no business advantage by completing the full certification process for their apps, why bother? It’s a reasonable perspective. Microsoft would obviously like developers to go the whole hog, but this might be an uphill battle.

One way that customers might help persuade developers that app certification is worthwhile is to allow users to grant consent for apps from verified publishers when apps require only “low-impact” permissions. The idea is that if less friction exists to deploy and use an app, it will be more popular and profitable.

The consent settings for a tenant are available in the Azure AD admin center (Figure 3) and include the ability to define what you consider to be low-impact permissions. In this case, the selected option allows users to grant consent, but only for three low-impact permissions such as the ability to read a user’s profile. Tenants can define what they consider to be low-impact permissions through the Permissions Classifications option shown in Figure 3.

Azure AD Consent and Permissions settings
Figure 3: Azure AD Consent and Permissions settings

Some will be uneasy about the prospect of users granting consents to apps. The safeguard is that consent is only possible for verified publishers; the counterargument is that developers can attain verification too easily to make this status truly valuable. If Microsoft 365 certified apps were the threshold, a different story might ensue. Microsoft recommends that it’s OK to allow users to grant consent to apps, but without stronger controls, this might be a stretch for many organizations.

The Rocky Road to App Certification

The situation is complex. Microsoft wants everyone to use modern authentication to access Microsoft 365. Getting to that position means a great deal of change for clients, apps, users, and organizations. Certification helps customers understand and control the access apps have to data in their tenant. That’s goodness, but only if ISVs co-operate and certify their products. Time enables change. While that happens, keep your app repository clean and tidy. You know it makes sense.

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