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What do SSH X.509 certs provide that DNSSEC and SSHFP RRs don't? SSH X.509 certs reminds of MTA-STS for SMTP, a shoe horning of the broken web PKI into another
by AndyMcConachie 7y ago
What do SSH X.509 certs provide that DNSSEC and SSHFP RRs don't? SSH X.509 certs reminds of MTA-STS for SMTP, a shoe horning of the broken web PKI into another protocol that doesn't need it.
Also, I'm not convinced that TOFU for SSH is really all that terrible. Maybe it's just my use case and my situation, but I SSH to the same servers over and over again. And if I need to give access to someone new I give them the public key first.
SSH X.509 looks like a complex solution to a not very big problem that can be more easily solved with DNSSEC and SSHFP.
- tptacek 7y agoWhat do SSH x.509 certs do that DNSSEC doesn't? Sure, I'll bite: * They put authentication to your SSH servers entirely under your own control, without escrowing keys to the operators of the TLDs. * They're deployable independently, without enrolling all of the rest of your infrastructure into DNSSEC and all its unreliability and complexity. * They integrate with IDPs, so that users can get short-duration authenticators based on MFA logins, without storing long-lived secrets on their machines. SSH X.509 certificates have nothing to do with the web PKI, other than that they use the same encoding. Engineering orgs that use SSH CAs run their own CAs. That's the point. Happy to have helped!
- gnufx 7y agoI'd expect a policy dictating using ephemeral certificates like Kerberos keys would actually have them for web services too, not just ssh (as with Globus).