메일 해킹으로 인한 수신/발신 정지 계정 해결방법 문의

Question

안녕하세요.

25.2.14(금요일)까지 정상적으로 업무를 본 후 25.2.16(일요일) 아침에 비정상적인 행동을 확인했습니다.(해킹 당함)

SMTP connection successful. Details:

• Host: smtp.office365.com
• Port: 587
• Email: ************
• Password: **********

Best regards,
Your SMTP Checker 2025

해당 메일이 수신된 후 몇몇 도메인에 공유되었고, 이후 한국시간 오전 5시경부터 7시경까지 수천개의 메일이 발송된 것으로 확인되었습니다.

확인 즉시 비밀번호를 변경하였으나, 과도한 메일 발신으로 계정의 메일 발신과 수신이 정지된 상황입니다.

내일(월요일)부터 업무를 시작하기 위해 이메일의 빠른 복구가 필요합니다.

절차서 등이 아닌 이 문제를 해결할 수 있는 정확한 링크를 알려주면 좋겠습니다.

빠른 답변 기다리겠습니다.

Answer 1

Hi, Younggeun Yoon

Sorry to disturb, we haven't received your news for a while, would you please allow me to know whether you've checked my last reply?

Please feel free to share with us if you have any questions or need further assistance.

Thanks for your kindness and your understanding would be highly appreciated.

Hope you all the best and wish you have a great day!

Sincerely,

Alex | Microsoft Community Moderator.

Answer 2

Hi, Younggeun Yoon

Thanks for your update and sorry for sharing the wrong resources from the above. (now it's has been edited, thanks for your understanding!)

Please be kindly to understand that for your Office 365 for education accounts which managing by your IT administrator, therefore, it is best to contact your administrator directly and ask your administrator to refer this official document - 손상된 전자 메일 계정에 응답 - Microsoft Defender for Office 365 | Microsoft Learn.

If you're not clear who is your administrator, please refer -어떻게 Microsoft 365 관리자를 찾을 수 있나요? - Microsoft 지원.

Also, based on your NDR - Non Delivery Report for "This message couldn't be delivered because the sending email address was not recognized as a valid sender." which shows that your account has been restricted. Therefore, please ask your administrator to follow the instructions based on - 제한된 엔터티 페이지에서 차단된 사용자 제거 - Microsoft Defender for Office 365 | Microsoft Learn. Your administrator has the permission and able to remove your account from the restricted list of your backend.

Note: Please be kindly to understand that for our community team that we only can guide you to find a solution or workaround. Since we do not have the authority to access into the backend. We usually give the advice for administrator users.

Thanks for your understanding and cooperation.

We hope you can get in touch with your administrator soon and unblock your account.

Sincerely,

Alex | Microsoft Community Moderator.

Answer 3

안녕하세요. 친절한 답변 감사합니다.

다만, 문제가 해결되지 않습니다.

비밀번호를 변경하였고, 로그인은 가능합니다.

다만, 해당 계정으로는 아직도 메일을 보낼 수 없고 받을 수 없습니다.

나는 다음과 같은 회신을 해결하는 방법을 원합니다.

Delivery has failed to these recipients or groups:

This message couldn't be delivered because the sending email address was not recognized as a valid sender. The most common reason for this error is that the email address is, or was, suspected of sending spam. Contact the organization's email admin for help and give them this error message.

내가 메일을 보내거나 받을 때 스팸메일을 보내는 것으로 의심되는 문제를 해결해 주시기 바랍니다.

Answer 4

Hi, Younggeun Yoon

Good day!

Thank you for posting to Microsoft Community. We are glad to assist you!

According to your description, I'm sorry to hear about the trouble you're experiencing with your email account.

First of all, please be kindly to understand for our community team which is a public place for sharing and discussing. Therefore, in order to protect your privacy, we have already removed your detailed email address and password. (Please do not share your password anytime!!!)

Back to your concern, to resolve this issue quickly, would you please allow us whether you're using an Office 365 for business account? 

If so, at this moment, you should contact your administrator of your organization as soon as possible.

Meanwhile, here is the direct link to the Microsoft support page for recovering a hacked or compromised account: Respond to a compromised email account - Microsoft Defender for Office 365 | Microsoft Learn. This page will guide your administrator through the necessary steps to regain access to your account and secure it from further unauthorized access.

Note: Please be kindly to understand that for our community team that we only can guide you to find a solution or workaround. Since we do not have the authority to access into the backend. We usually give the advice for administrator users.

Good luck, and I hope your account gets resolved quickly!

Thanks for your precious time and your understanding would be highly appreciated.

Hope you all the best!

Sincerely,

Alex | Microsoft Community Moderator.