Spam email received with empty <> Sender address. How do we block this?

Said A 706 Reputation points
2023-03-28T18:03:16.18+00:00

Hello everyone,

I have this issue where spam email recieved from an empty email address with <> like the below screenshot:

User's image

I have tried creating a new rule to detect "<>" from the sender address and block it. The rule is not working.

Let me know if you have any feedback or advice,

Thank you!

Regards,

Microsoft Exchange Online
Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
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  1. Andy David - MVP 141.5K Reputation points MVP
    2023-03-28T18:18:28.6933333+00:00

    I would submit that as junk to Microsoft from the explorer Email entity menu:

    User's image


  2. Aholic Liang-MSFT 13,741 Reputation points Microsoft Vendor
    2023-03-29T06:13:22.5933333+00:00

    Hi @ Said A ,

    Please refer to the following two conditional setting mail flow rules to see if you can block messages with empty sender addresses:

     

    1. Delete messages whose sender address matches “<>” or “space” characters:

     

    2023-3-29-1

    1. Delete all messages from outside your organization, except for the sender address that matches the "@" character.

     2023-3-29-2


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