When dealing with external users in Microsoft Teams, you would find yourself having to add users to your Teams, and when this functionality is enabled across your organization, you would want to have a way to review this access in order to have more control on who can access resources in your environment, in this case, it’s Microsoft Teams.
The way we can do it is by utilizing Azure Access Reviews which is available in Azure AD Premium P2. By using Access Reviews, we can create a policy to remind Teams Owners or basically anyone in the tenant to be responsible for reviewing the guest access on these teams. We can choose to review all teams guest access in the environment, or select specific teams. We can schedule the access review to be done on regular basis and having decisions made upon review completion. For example, if a guest is denied access to one Team, then remove the guest completely from the tenant or just remove the guest from that specific Team.
Let’s dig into how this actually works. I’ll first invite a Gmail user to my Team as a guest user:
Users will get an email notifying them that they were added to the team:
Note that even as a Gmail user, you can be added to multiple tenants, and sign in with your Gmail account, you will be able to see the tenants just like any normal Teams user who’s using his/her Microsoft 365 accounts:
Now, we’d like to review this Employee Onboarding Team, since, let’s assume it contains lots of guest users. Remember we can set the review access to be done across many teams that have guest users, but in our scenario we’ll do it just one for one to demonstrate how it works. Head over to Microsoft Azure AD, click on Identity Governance, then click on Access Reviews:
Now we’ll need to create a new Access Review, so we’ll click on New access review and choose Teams + Groups. It will ask us if we want to create the access review for guests across all Teams or just select specific Teams, in our case we’ll select a specific team and set the scope to Guest users only.
In the reviewers selection, we can decide if the group/team owner should be the one doing the review, or select a specific person, or even let users review their own access. In preview, it allows current user’s manager to review their access, which depends on the manager’s property in the user’s profile.
Next comes the scheduling, and how it works is that you define the recurrence, to either happen one time or on a Weekly/Monthly/Quarterly/Semi-annually or Annual basis. So in my case I’ll define Weekly and set the duration to 3 days. 3 days means that the reviewer will have 3 days to review the status, after that there’s a job that will run and make a decision upon the current reviewers selection. I’ll get to this point later in this post but let’s continue with defining the schedule. You can choose the start date and the end date of this schedule, and then hit Next.
The next page tells you if you want to apply a decision to the resource (being user’s access to that resource), so make it enabled. There’s also an option on what to do if the reviewer doesn’t respond, which allows you in this case to choose on whether to keep the user’s access to the resource (the team) or deny it. The next option defines what happens when the access is denied which is really cool. You can define if the user’s permissions is removed from that team but still gets access to your tenant as a guest or being removed from the tenant completely.
Other options on the page are self-explanatory, however one thing that is worth mentioning is the decision helper, which will provide you with recommendations when you actually start the review process and will advise you on whether to approve or reject the access. Now you can give your access review a name and hit Create, and we’ll have our access review ready.
Now when the date of the review arrives, you as a reviewer will receive an email asking you to start the review process:
When you click on Start review you will be redirected to Access reviews page where it will list all the reviews that you need to complete. In my case I’ll deny the access for this user even though the recommendation by Azure is to approve it (remember that you can enable recommendations when you configure the access review):
Now here’s the catch. Even though you clicked on deny and you expect the user to be removed from the team, it won’t be removed.. why? This actually confused me at the start, but the actual decision is applied when the review period ends. So if you set the period schedule to weekly and the period duration to 3 days, it will wait for 3 days until it acts upon your decision even though you made the decision on the first day. So you actually have sometime during the period to change your mind and approve the user’s access again. When the period ends, you will get an email telling you that the review ended and your decision will be applied to the resource (the team):
Now that the review decision has been applied, head over to Microsoft Teams, and you’ll see that the guest user is gone! Such a nice way to do reviews across many teams which is really beneficial for large organizations with many guest users all over the place!