Enhancing Security for Shared Mailboxes: Seeking Best Practices and Advice

Question

Hello,

I want to enhance the security level of access control for our shared mailboxes. Currently, users are being added individually to manage access, which is not ideal.

In my opinion, distribution lists (DLs) are best suited for sharing news with a large number of people at once, rather than for managing access to shared mailboxes. To improve security, I’ve started using security groups for this purpose, and it works efficiently. However, there’s an issue: when I add a user individually, the shared mailbox appears automatically in their Outlook. But when I add the user to a security group, the shared mailbox does not appear automatically.

Can you advise on the best practices and standard methods to securely handle this situation?

Thanks.

Answer 1

If Automapping is a requirements, you don't have a choice really - this only works when granting permissions individually to the user, nor via group. The alternative it to educate users how to add the shared mailbox as additional account in Outlook (via File > Add account) or OWA (Open another mailbox feature)... which might be a harder task :)

Answer 2

Hi, @Al Khazragy Laith

From your description, I understand that after you add a user to a security group, the shared mailbox does not appear in Outlook.

As Vasil Michev said, auto-mapping only works if you assign permissions to individual users, but not for groups. And when you assign full access to a security group, the shared mailbox does not appear in each user's Outlook file. This is also confirmed by the screenshots and articles below.

More information can be found Manage permissions for recipients | Microsoft Learn

In addition, you can follow Vasil Michev, and you can also try the following methods to check and add a shared mailbox to the folder pane.

1.Check if MAPI is enabled for the affected shared mailbox in Exchange admin center.

Exchange admin center > Recipients > Mailboxes > select the shared mailbox > manage email apps settings.

2.In OWA, right click on folders in the folder pane > Add shared folder or mailbox > type the shared mailbox name/email address.

Then the shared mailbox will appear in the folder pane.

Similar threads are available for your reference Shared Mailbox permissions to security group not showing in Outlook? - Microsoft Q&A

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