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FredrikPalsson's avatar
FredrikPalsson
Copper Contributor
Nov 01, 2021
Solved

User able to read and reply on behalf of shared mailbox, but is not a member of it

One of our global admins ended her employment this Friday. Before signing out she somehow gave one of our users access to one of our shared mailboxes. Everything works as expected, the shared mailbox can be read and replied on behalf of this user. 

 

BUT the new user of the mailbox is not listed as a member anywhere in the O365 admin gui. How is that possible? Even when querying using PowerShell as in https://o365reports.com/2020/01/03/shared-mailbox-permission-report-to-csv/, the new user is nowhere to be found.

Can anyone give an explanation for this?

  • VasilMichev's avatar
    VasilMichev
    Nov 03, 2021
    If added as additional account, there is a possibility that the user has directly entered the username/password for the shared mailbox. This is technically possible, all you need to do is generate a password for the shared mailbox account (as admin), however it is not a supported scenario,

6 Replies

    • FredrikPalsson's avatar
      FredrikPalsson
      Copper Contributor

      VasilMichevI guess you mean permissions on the actual inbox, sent items and so on?

       

      There are only two entries on all of those: Default and Anonymous. They both have no permissions.

       

      Any other suggestions?

      • VasilMichev's avatar
        VasilMichev
        MVP
        There are no other options. Does the Full access permission list any groups that he might be a member of? How is he accessing the shared mailbox, which client is he using? If using Outlook on the desktop, how is the shared mailbox added (File > Add account or File > Account settings > More > Advanced ...)

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