Mail Delivery Subsystem Scam | How the Scam Works

The “Mail Delivery Subsystem” scam is a phishing or spoofing scheme that exploits automated email bounce messages to trick users into clicking malicious links, downloading malware, or giving up personal information.

Hereโ€™s a breakdown of how the scam works, what to look out for, and how to protect yourself.


๐Ÿ” What Is the โ€œMail Delivery Subsystemโ€ Scam?

The Mail Delivery Subsystem is a legitimate system used by email servers (like Gmail, Yahoo, Outlook) to notify senders that their email couldnโ€™t be delivered. A typical bounce-back email has a subject like:

Mail Delivery Subsystem: Delivery Status Notification (Failure)

Scammers spoof or fake this kind of message to make it look like it comes from a trusted server, but it actually contains malicious links, attachments, or phishing tactics.


๐Ÿง  How the Scam Works

  1. You receive an email that looks like a system-generated bounce-back from an address like:

    mailer-daemon@googlemail.com
    postmaster@mail.domain.com

    (These are often spoofed to look legitimate.)

  2. The message claims your email couldnโ€™t be delivered. It may include:

    • A fake error message.

    • A link to โ€œview the undelivered message.โ€

    • An attachment (usually a .zip or .html file).

    • A request to โ€œresendโ€ or โ€œverifyโ€ your credentials.

  3. If you click the link or open the attachment:

    • You could be redirected to a phishing site that steals your login info.

    • Malware (like a keylogger or ransomware) may be downloaded.

    • Your email account may get hijacked and used to send spam.

Also Read : hello@emails.reebok.com | Is it a Legitimate Reebok Email


โš ๏ธ Signs Itโ€™s a Scam

  • The email says you sent something you didnโ€™t (e.g., to an unknown recipient).

  • Poor grammar or formatting in the message.

  • The โ€œView Messageโ€ button or link leads to a non-Google / non-Microsoft URL.

  • The senderโ€™s email address looks slightly off (e.g., googlemail.support or mailer-daemon-alerts.com).

  • It includes unexpected attachments or urgent calls to action like:

    โ€œClick here to recover your message.โ€
    โ€œLogin to verify your email.โ€


โœ… What To Do If You Get One

  • Donโ€™t click anything.

  • Donโ€™t open attachments.

  • Check the full email headers to verify the sender.

  • Delete the message.

  • Report it as phishing (in Gmail, Outlook, etc.).


๐Ÿ›ก๏ธ How To Protect Yourself

  • Enable 2FA (Two-Factor Authentication) on your email.

  • Use a reputable antivirus program and keep it updated.

  • Be skeptical of email delivery failures when you havenโ€™t sent anything.

  • Regularly review your sent messages for suspicious activity.

  • Use a password manager to avoid entering credentials on fake sites.


๐Ÿ“Œ Summary

Legit Bounce Scam Bounce
Sent after you email someone Random / no message was sent
No links or attachments Includes links or files
From your email providerโ€™s domain Spoofed or unusual domain
Just informs you โ€“ no action needed Urges you to click or enter credentials