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Failed log on (Failure message: Account is locked because user tried to sign in too many times with
I have the same issue.
Did you get anywhere with a proper answer or solution ?
I have daily more than 500 login tries from China, US, Thailand etc. with failed login using IMAP.
Failure reason "Account is locked because user tried to sign in too many times with an incorrect user ID or password."
IMAP disable in exchange and Block Legacy Cond. Access is applied, how can I tell if we are not in trouble if I still get 50053 error when service is disabled ?
thank you
LilleLars As @Vasil Michev said the CA policies are only being applied AFTER succesful authentication through basich auth protocols (POP3, IMAP, SMTP, etc.). That's why you're seeing this behaviour.
To eliminate these spray attacks you need to disable basic auth in Exchange Online. Please have a look at the following article on how to do that: https://docs.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/disable-basic-authentication-in-exchange-online
Thank you Pavel, im testing now and this tenant did not have any "authentication policies" already.
Ive done this:
New-AuthenticationPolicy -Name "Block Basic Auth"
Set-OrganizationConfig -DefaultAuthenticationPolicy "Block Basic Auth"gives me below result which looks good.
I´ve waited 10 hours and stille I see IMAP error 50053 "account is blocked" in the Sign-ins log
Hope I did it correct?
AllowBasicAuthActiveSync : False
AllowBasicAuthAutodiscover : False
AllowBasicAuthImap : False
AllowBasicAuthMapi : False
AllowBasicAuthOfflineAddressBook : False
AllowBasicAuthOutlookService : False
AllowBasicAuthPop : False
AllowBasicAuthReportingWebServices : False
AllowBasicAuthRest : False
AllowBasicAuthRpc : False
AllowBasicAuthSmtp : False
AllowBasicAuthWebServices : False
AllowBasicAuthPowershell : FalseLilleLars The steps you've done are correct and should be enough. If you're seeing this for a specific user account you can check he has the policy applied and run "Get-User -Filter "AuthenticationPolicy -eq..." (more info in the article) to make sure. But other than that I think you've done all that was needed and the basic auth should be blocked 😞 You might wait a bit longer and see if it works eventually. Maybe someone else has an idea.
