It then asks for the user's password and checks against the rules in the /etc/sudoers file whether the user is allowed to run ...

Access the file and open it with visudo. Do not open the sudoers file with a normal text editor. You can now use your YubiKey ...

Otherwise, no dice. There’s quite a bit more you can do with sudoand sudoers. However, you should resist the urge to do too much. It is easy to make assumptions about security that get you in ...

Alternatively, you can also use the getent command. There's also the /etc/sudoers file, which, if you can edit it somehow, will allow modifying the sudo permissions for users and groups.