oss-sec mailing list archives
Re: Python standard library defaults to insecure TLS for mail protocols
From: nightmare.yeah27 () aceecat org
Date: Fri, 2 Feb 2024 12:30:22 -0800
On Thu, Feb 01, 2024 at 09:27:15PM +0100, Hanno Böck wrote:
Relaying *MTAs* do not usually verify the certificate of the server they connect to.
Even that isn't true any more in 2024. The largest mail providers (and plenty of small ones) all support MTA-STS. So in most cases, certificate validity and hostnames are checked.
When they do, it creates problems because MTA certificates are very often self-signed. IIRC Yahoo relays in particular used to have this problem (or still do?)
Doubtful: host -t txt _mta-sts.yahoo.com _mta-sts.yahoo.com descriptive text "v=STSv1; id=20161109010200Z;"
If they had invalid certs, they wouldn't receive any mails from MTA-STS supporting senders. I think someone would've noticed.
I see little point in re-litigating the rest of the argument, but I should note that I meant this the other way. Yahoo used to be the one major *sender* provider that checked the recipient certs, and when it failed it fell back to plaintext. -- Ian
Current thread:
- Python standard library defaults to insecure TLS for mail protocols Hanno Böck (Feb 01)
- Re: Python standard library defaults to insecure TLS for mail protocols nightmare . yeah27 (Feb 01)
- Re: Re: Python standard library defaults to insecure TLS for mail protocols Hanno Böck (Feb 01)
- Re: Python standard library defaults to insecure TLS for mail protocols Steffen Nurpmeso (Feb 02)
- Re: Python standard library defaults to insecure TLS for mail protocols Kurt H Maier (Feb 02)
- Re: Python standard library defaults to insecure TLS for mail protocols Steffen Nurpmeso (Feb 02)
- Re: Re: Python standard library defaults to insecure TLS for mail protocols Hanno Böck (Feb 01)
- Re: Python standard library defaults to insecure TLS for mail protocols nightmare . yeah27 (Feb 02)
- Re: Python standard library defaults to insecure TLS for mail protocols nightmare . yeah27 (Feb 01)
- Re: Re: Python standard library defaults to insecure TLS for mail protocols Daniel Kahn Gillmor (Feb 02)
- Re: Python standard library defaults to insecure TLS for mail protocols Jeremy Stanley (Feb 01)
- Re: Python standard library defaults to insecure TLS for mail protocols Stuart D Gathman (Feb 02)