CVE-2023-51764

Postfix SMTP Smuggling - Expect Script POC

send an email that is legitimate, but inside the email there is many others emails (different senders, recipients, subjet, etc). The initial email is check for SPF/DKIM/DMARC, the others inside are not !

usage: ./cve-2023-51764.sh mx.fqdn port
./cve-2023-51764.sh mail.mydomain.com 25

notes: chmod +x cve-2023-51764.sh
require app expect
require legitimate ip sender and email sender (to pass SPF, DKIM, DMARC)

result:

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Kudos: https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide
Workaround/Fix: https://www.postfix.org/smtp-smuggling.html

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