Possible bug: SSH doesn't prefer host keys listed in SSHFP records while connecting.

Christoph Anton Mitterer calestyo at scientia.net
Mon Feb 25 13:05:49 AEDT 2019


On Mon, 2019-02-25 at 04:18 +0300, Yegor Ievlev wrote:
> Well, the most likely entity who can do that is your registrar, since
> it can change your nameservers and DS records.

Or the registry, the IANA, respectively any authority in between which
controls a DNS zone.


Also, the typical way one communicates "securely" with the registrar,
is via TLS, which is because of the certificate model inherently
broken.
Mozilla, e.g. ships around 150 root CAs, many of whom are known to be
not trustworthy... with probably thousands of intermediate CAs, all
which can basically issue anything.

SSHFP is IMO mostly interesting for organisations which maintain their
own secure DNS resolvers (i.e. with their signing keys being configured
as trust anchors).
But even then you have probably different security properties than with
normal SSH keys that were directly exchanged via some trusted path
(namely the single point of failure).

Cheers,
Chris.



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