4 ms·

This really wants me to re-evaluate all the times I have gracefuly TOFU'd while SSHing into a machine or even logging onto a website.

lukevp 3y ago
What does TOFU mean in this context? I haven’t heard that word related to tech before OpenTofu just recently!
- holmesworcester 3y ago
  Trust On First Use
- deleted 3y ago
  [deleted]
- sirl1on 3y ago
  Trust On First Use. No relation to OpenTofu where Tofu is a word play in TerraForm.
- mmh0000 3y ago
  https://en.wikipedia.org/wiki/Trust_on_first_use https://en.wikipedia.org/wiki/Trust_on_first_use
marcosdumay 3y ago
Given that the attack subverted the TLS certificates, I'd say key-based TOFU is still a better alternative. Of course, checking the server key is better than not doing so, but any knee-jerk response to TOFU will probably make your security worse.
rodlette 3y ago
Consider including SSH known hosts in your cfgmgmt. I have all my machines' public keys, and all major git forge's SSH keys in my git-managed cfgmgmt repo. For NixOS users: https://search.nixos.org/options?channel=23.05&show=programs.ssh.knownHosts https://search.nixos.org/options?channel=23.05&show=programs...
- ehPReth 3y ago
  one issue is that most hosting providers don't display ssh host keys anywhere in the control panels so unless you have a... lot of fun (and spend time) with the virtual console... (or maybe a custom cloud-init script?) you're SOL for the very very first connection
  - rudasn 3y ago
    Isn't more important that the known key does not change unless you made the change, than having the "right" key to begin with?
    - ehPReth 3y ago
      hmmmm... if someone MITMs you the first thing could they 'in theory' just change the key on the host to match the MITM one?
0xbadcafebee 3y ago
At DEFCON, fifteen years ago, MITM'ing TOFU ssh connections was what you did when you were bored in between talks. If you wanted to capture a new first connection, just keep dropping connections until they try a different host or device. I don't really get why people use ssh at all if they aren't using certs. Might as well use telnet.
thriftwy 3y ago
An unknow key when connecting to a known server will raise all kinds of alarms in my head.

lukevp 3y ago

What does TOFU mean in this context? I haven’t heard that word related to tech before OpenTofu just recently!

holmesworcester 3y ago
Trust On First Use
deleted 3y ago
[deleted]
sirl1on 3y ago
Trust On First Use. No relation to OpenTofu where Tofu is a word play in TerraForm.
mmh0000 3y ago
https://en.wikipedia.org/wiki/Trust_on_first_use https://en.wikipedia.org/wiki/Trust_on_first_use

marcosdumay 3y ago

Given that the attack subverted the TLS certificates, I'd say key-based TOFU is still a better alternative. Of course, checking the server key is better than not doing so, but any knee-jerk response to TOFU will probably make your security worse.

rodlette 3y ago

Consider including SSH known hosts in your cfgmgmt. I have all my machines' public keys, and all major git forge's SSH keys in my git-managed cfgmgmt repo. For NixOS users: https://search.nixos.org/options?channel=23.05&show=programs.ssh.knownHosts https://search.nixos.org/options?channel=23.05&show=programs...

ehPReth 3y ago
one issue is that most hosting providers don't display ssh host keys anywhere in the control panels so unless you have a... lot of fun (and spend time) with the virtual console... (or maybe a custom cloud-init script?) you're SOL for the very very first connection
- rudasn 3y ago
  Isn't more important that the known key does not change unless you made the change, than having the "right" key to begin with?
  - ehPReth 3y ago
    hmmmm... if someone MITMs you the first thing could they 'in theory' just change the key on the host to match the MITM one?

0xbadcafebee 3y ago

At DEFCON, fifteen years ago, MITM'ing TOFU ssh connections was what you did when you were bored in between talks. If you wanted to capture a new first connection, just keep dropping connections until they try a different host or device. I don't really get why people use ssh at all if they aren't using certs. Might as well use telnet.

thriftwy 3y ago

An unknow key when connecting to a known server will raise all kinds of alarms in my head.