On 12/10/18 6:11 PM, Viktor Dukhovni wrote:
On Dec 10, 2018, at 8:19 PM, Alice Wonder <al...@domblogger.net> wrote:Even in this thread someone pointed out that Debian defaults to 1024-bit RSA. You end up with things like SHA1 still enabled because upstream thought the compatibility mattered more than the security. So yes, I made a typo, and maybe I'm not a guru but the reason why I fiddle with this stuff is because when I didn't - too often the "experts" left things in a way that were dangerous.The dangers of SHA1 and RSA1024 are overhyped. Walk don't run to better options when interoperable, and don't set the bar too high, lest you get reduced security by degrading lesscapable peers to cleartext.
It is my philosophy that "less is more" with cipher suites that resulted in 3DES and RC4 being disabled already on my servers (in general, not just mail servers) long before that was recommended.
It is the fear of the plain text that kept SMTP dangerous for so long, with expired certs and mis-matched hostnames the norm because why should an admin bother to keep them accurate when they work?
It is the responsibility of the client to not send if the connection is not secure, if the client wants to guarantee security for those it sends for. Using a reduced cipher lists means there is less illusion of security where it doesn't actually exist.
If the client doesn't support the quality ciphers, it isn't really secure, so it SHOULD be plain text so that it is obvious it is not secure. That's my philosophy. It's not a popular philosophy but it is my philosophy. And with that philosophy, I haven't found myself supporting known broken ciphers in years. They have been disabled long before the weaknesses were discovered because I believe less is more.
The cipher list with my typo was Dovecot config, where it doesn't fall back to plain text with IMAPS. It refuses the connection.
-- For signature trust anchor (paranoid only need worry 'bout this): https://ca.pipfrosch.com/pipfrosch-cacert-pem.crt Webmail clients, sorry, out of luck, you can't import it. Get an actual e-mail app.
smime.p7s
Description: S/MIME Cryptographic Signature
