With sudo, you can either set it to ask for a password or not ask for a password.
Historically, everything was password-protected, which is the model that I am used to. However, encryption seems to be favoring public/private key authentication more and more nowadays.
This is evident in the fact that when I spin up a server on GCP, AWS, or DigitalOcean, I don't get a password. Instead I get a key that I use to log in.
Now, if I want to do
sudo when I am logged in, it doesn't ask me for a password. This is obviously due to the fact that a password was never given to me, only a key was. And sudo doesn't ask for a password because of the following rule in
ubuntu ALL=(ALL) NOPASSWD:ALL
This is fine for one user. But what happens if a server has 3-4 users, all of whom need sudo access, and all of whom are using keys to log in rather than a password. You want to make sure that one user can't do
sudo su - <someone else's username> sudo <command>
Is the encouraged practice to not allow password authentication when connecting with sshd, but to give all the users a password that is used for
sudo authentication? Or to use pam_ssh_agent_auth to allow sudo to authenticate with another set of private/public keys that have a passphrase? Or is there something else that should be done?