4 ms·

SSH doesn't get this right. It's no better than a (auto-pinned) self-signed cert, in our world. I challenge everyone to find in their extended group of friends

SSH doesn't get this right. It's no better than a (auto-pinned) self-signed cert, in our world. I challenge everyone to find in their extended group of friends and colleagues, and their friends and colleagues, a single person who consistently checks the fingerprint* on every first SSH connection. Id personally have a hard time finding someone who even knows it matters. And if you don't? Mitm can get your password, or tunnel your key to another host, bar some crazy ~/.ssh/config which nobody has. WiFi's WPA2 actually does this better than SSH; the passphrase authenticates both parties to eachother, not just one way. I can't set up a hotspot with your home SSID and intercept your PSK---even on initial connection. SSH: nice in a cryptographic utopia, not better than self signed SSL certs when applied to human beings. SSH is just not suitable for humans. Apparently. * a significant part of it, not just the security-through-obscurity random 2 letters in the middle and the last four.

ryanlol 11y ago
-o VisualHostKey=yes
- nothrabannosir 11y ago
  A band-aid, I'm afraid. Without going into the question of how many bits of entropy that actually has when used with human beings in real settings, and just assume it's a perfect check; my question stands: how many people can you find who use this? Many SSH clients don't even support it, at all. PuTTY and almost anything that uses SSH for tunneling. When they do: how many of your hosts do you know the image of? Again: nice idea, but utterly impotent in our universe. Compare to the efficiency of e.g. WPA2 keys: less theoretically beautiful, but much more efficient with humans.
  - ryanlol 11y ago
    >Without going into the question of how many bits of entropy that actually has when used with human beings in real settings, and just assume it's a perfect check; my question stands: how many people can you find who use this? Probably not very many, but it's really only useful for people that ignore basic security features anyway. (Key auth) >When they do: how many of your hosts do you know the image of? None, I use key auth like any reasonable person would.
    - nothrabannosir 11y ago
      Does key auth protect you from a MITM on the first connection? That is, key auth as reasonable people use it, as you said. And this: > but it's really only useful for people that ignore basic security features anyway. (Key auth) is precisely the point: that's a lot of people. SSH doesn't work for those people. We can play the blame game, but at the end of the day, clearly something is "not right". And these are people who use SSH to begin with. Not typically technologically illiterate, I would guess. If they can't even be arsed to use "basic security features", what good is this system, then? Again: there is a way to use SSH properly, yes. But rare is the person who does this. (But key auth is orthogonal to host fingerprinting anyway, this is kind of a red herring)
      - ryanlol 11y ago
        >Does key auth protect you from a MITM on the first connection? Yes. Key auth will protect you from your SSH connection being listened to, and will make credential theft reliant on social engineering. However, someone could still pretend to be the server (potentially stealing your commands), but there really doesn't exist any way to solve that. >is precisely the point: that's a lot of people. SSH doesn't work for those people. We can play the blame game, but at the end of the day, clearly something is "not right". Nothing works for those people, at least generally with SSH users you can assume that they should know better. >Again: there is a way to use SSH properly, yes. But rare is the person who does this. I'd hardly consider SSH key auth users rare. >(But key auth is orthogonal to host fingerprinting anyway, this is kind of a red herring) But it almost completely fixes the main problem caused by MitM, someone gaining access to the server you're logging into.
cellularmitosis 11y ago
Still, there's a difference between being less than 100% secure and being a totally useless feature. Being able to make the statement "Either you've been consistently MitM'ed by the same entity for the past three years, or the your little cloud-based debian box is actually secure" is a lot more useful than not tracking SSH fingerprints at all. I certainly wish my browser would track my self-signed certs in this way.

ryanlol 11y ago

-o VisualHostKey=yes

nothrabannosir 11y ago
A band-aid, I'm afraid. Without going into the question of how many bits of entropy that actually has when used with human beings in real settings, and just assume it's a perfect check; my question stands: how many people can you find who use this? Many SSH clients don't even support it, at all. PuTTY and almost anything that uses SSH for tunneling. When they do: how many of your hosts do you know the image of? Again: nice idea, but utterly impotent in our universe. Compare to the efficiency of e.g. WPA2 keys: less theoretically beautiful, but much more efficient with humans.
- ryanlol 11y ago
  >Without going into the question of how many bits of entropy that actually has when used with human beings in real settings, and just assume it's a perfect check; my question stands: how many people can you find who use this? Probably not very many, but it's really only useful for people that ignore basic security features anyway. (Key auth) >When they do: how many of your hosts do you know the image of? None, I use key auth like any reasonable person would.
  - nothrabannosir 11y ago
    Does key auth protect you from a MITM on the first connection? That is, key auth as reasonable people use it, as you said. And this: > but it's really only useful for people that ignore basic security features anyway. (Key auth) is precisely the point: that's a lot of people. SSH doesn't work for those people. We can play the blame game, but at the end of the day, clearly something is "not right". And these are people who use SSH to begin with. Not typically technologically illiterate, I would guess. If they can't even be arsed to use "basic security features", what good is this system, then? Again: there is a way to use SSH properly, yes. But rare is the person who does this. (But key auth is orthogonal to host fingerprinting anyway, this is kind of a red herring)
    - ryanlol 11y ago
      >Does key auth protect you from a MITM on the first connection? Yes. Key auth will protect you from your SSH connection being listened to, and will make credential theft reliant on social engineering. However, someone could still pretend to be the server (potentially stealing your commands), but there really doesn't exist any way to solve that. >is precisely the point: that's a lot of people. SSH doesn't work for those people. We can play the blame game, but at the end of the day, clearly something is "not right". Nothing works for those people, at least generally with SSH users you can assume that they should know better. >Again: there is a way to use SSH properly, yes. But rare is the person who does this. I'd hardly consider SSH key auth users rare. >(But key auth is orthogonal to host fingerprinting anyway, this is kind of a red herring) But it almost completely fixes the main problem caused by MitM, someone gaining access to the server you're logging into.

cellularmitosis 11y ago

Still, there's a difference between being less than 100% secure and being a totally useless feature. Being able to make the statement "Either you've been consistently MitM'ed by the same entity for the past three years, or the your little cloud-based debian box is actually secure" is a lot more useful than not tracking SSH fingerprints at all. I certainly wish my browser would track my self-signed certs in this way.