4 ms·
That is completely insecure. A MITM would just block access to the tls-on-connect port, forcing the sending host to retry on port 25, where they would strip the
by mike-cardwell 8y ago
That is completely insecure. A MITM would just block access to the tls-on-connect port, forcing the sending host to retry on port 25, where they would strip the STARTTLS advertisement.
Unless you're recommending to not fall back to port 25 after a failed connection to the tls-on-connect port. In which case, see the comment you were replying to where I said it would be backwards incompatible.
Both of the solutions I mentioned are backwards compatible, and protected from a similar downgrade situation.
- drudru11 8y agoRight, I should have said that I was recommending not ever sending on 25. The STARTTLS mitm is just too easy for large attackers. IMHO, being backwards compatible is necessary for a transition period. The messaging to SMTP operators should be... get on board, or you are going to start losing mail in 1 year. Even Chrome is going to show all http as insecure in the very near future. Which reminds me... I need to get all my sites upgraded.