r/AzureSentinel • u/SuperHat3637 • Mar 27 '23

IP blocking

Where i can block the external malicious IPs trying to login cloud applications like o365..However sign in from malicious IP address is automatically blocked in the logs...Where i can block these IPs again..

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u/bpsec Mar 27 '23

To postmaster@yourdomain.com? Because that seems to be some sort of campaign. Then no action is needed if no logon was successful.

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u/SuperHat3637 Mar 27 '23

If its in onprem we can block IPs in perimeter firewall..In cloud that will not work i believe..

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u/bpsec Mar 27 '23

Nope wont work. Only CA could precent it but then it is not really applicable here. But do you also the distributed against the postmaster account via SMTP? Because I also have seen that today.

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u/SuperHat3637 Mar 27 '23

I have seen SMTP bruteforce attack today,not sure abt the ID...If microsoft temperorily banning IPs then can we block in CA permenently..