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Did you know that if a spammer uses your email address as the FROM: address, which is easy to do, all the bounce messages will go to your email address? If the spammer really hates you, they will send (hear-me.social)

submitted 2 months ago by [email protected] to c/[email protected]

37 comments fedilink hide all child comments

Can you stop this or prevent this? No

Why would a mail provider send you a bounce message, knowing you're innocent? Because that's how someone wrote the protocol back then, and nobody changes it or does it differently because ... reasons.

Does the spammer get a bounce message? Nope, not one.

Does the SMTP sending account owner whose credentials were stolen be notified about bounces so they can stop the spam? Nope.

Just millions of emails sent every day to poor schlameels who have no idea why they are getting them and who can't do anything about them.

The more I learn about the email protocols, the more I realize how terrible the design is.

#emailsecurity #spoofing #cybersecurity #spam

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[–] [email protected] 13 points 2 months ago (8 children)

SPF

DKIM

Dmarc

You might want to learn about those as well.

[–] [email protected] 3 points 2 months ago (7 children)

@[email protected] People are not reading. You are not reading.

SPF, DKIM and DMARC are not relevant. Those are instructions to the receiving servers which are not the ones sending the bounces. The receiving server is telling the sending server, based on these DNS records, that it will not accept the message. It refuses them. Period. No bounce message.

The sending server then, as a courtesy, lets the sender know, solely based on the FROM: address, that the email could not be delivered, as one by one messages.

There are no DNS records or configurations that control this. The SMTP server follows the protocol which is to inform the FROM: address, as a courtesy, that the email was not accepted. It is the sender. It does not look at SPF, DMARC, and DKIM rules. That is only what the destination server uses.

[–] [email protected] 2 points 2 months ago (1 children)

Is the recipient server drops or quarantines spam instead of rejecting it (which is standard best practice), the sending server will never know, and won't send a message back to the sender.

[–] [email protected] 1 points 2 months ago

DMARC has only 3 options. Ignore, reject or quarantine. There is no "drop" instead of "reject". And anything other than an "ignore" will cause a reject from the receiving server back to the sending server who will then inform the FROM address that the email was not delivered.

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