Corrupted email header

Question

Hello Community,

I try to find a way how emails with a header of 3 lines can be blocked by Exchange Online Protection:

This is one example of many emails that are not identified as phising.

I could not find a mail flow rule to prevent such emails from being delivered. The phishing threshhold could be increased to 4, ATP is in place.

best regards,

Viktor

Answer 1

Hi Katherine,

many thanks for your response.

I am not sure about this statement "In fact, mail flow rules do have this condition emails with a header of 3 lines." - can you please explain in more detail?

I want to understand if there is a way how I can prevent a delivery of an email that contains a email header with only three lines.

thanks,

Viktor

Answer 2

Hi Viktor Reinoch,

How is your problem going? Please feel free to let me know.

Best Regards,

Katherine

Answer 3

Hi Viktor Reinoch,

Thanks for choosing Microsoft Community.

Based on your description, I know your requirement. And I did some further research for you. So sorry to bring you inconvenience. In fact, mail flow rules do have this condition emails with a header of 3 lines. You can get more detailed information about Mail flow rules conditions via Mail flow rule conditions and exceptions (predicates) in Exchange Online | Microsoft Docs. Your understanding and patience are highly appreciated.

If you have any other problems, welcome to Microsoft Community. We are willing to provide you help.

Thanks for your precious time. Have a nice day.

Best Regards,

Katherine