Comment by PhilipRoman
8 days ago
>>Nobody verifies host keys,
>The known_hosts file is verification of host keys
I think the point was that those devices typically generate host keys dynamically and therefore the host key verification is usually turned off, leaving you just with encryption (which is still better than telnet - at least you're safe against passive adversaries). At least that's what I've seen in practice.
Host key verification is a client feature and is on by default. Have you really never gotten the giant warning after a reinstall? That's what that is. SSH is telling you that the server has changed and isn't what you think.
I'm saying that 90% of these setups look like this (or do the equivalent thing manually):
They have ssh, but no proper key management
Well, sure. You can turn off host key checking in ssh! But that isn't responsive to a point that (1) host key validation exists in ssh and (2) host key validation is on by default in ssh.
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Exactly. But 'passive encryption' isn't helpful; if you can see the traffic, you can MITM it. Just RST the connection, wait for the reconnect, intercept.