Now pass the USB ID ( 1050:0407) as follows to find out other info about the key: Here is what I see: Bus 001 Device 022: ID 1050:0407 Yubikey 4 OTP+U2F+CCID Is YubiKey detected on my Linux? Run the lsusb command: $ ssh linode-nixcraft-01 - dpkg -list | grep openssh-server $ ssh linode-nixcraft-01 - lsb_release -a Here is what I have on my Linux desktop and server fetched using the ssh command. In OpenSSH, FIDO devices are supported by new public key types “ecdsa-sk” and “ed25519-sk”, along with corresponding certificate types.

U2F/FIDO are open standards for inexpensive two-factor authentication hardware that are widely used for website authentication. OpenSSH version 8.2 or above adds support for FIDO/U2F hardware authenticators to OpenSSH. It would be best to have at least OpenSSH version 8.2 or above installed on both client and server. The YubiKey is a hardware authentication device manufactured by Yubico to protect access to computers, networks, and online services that supports one-time passwords, public-key cryptography, authentication, and the Universal 2nd Factor (U2F) and FIDO2 protocol.

Once logged into bastion host, you can access all other cloud servers easily. The server generally hosts an sshd process, and all other services are removed. It is a special-purpose server on a network specifically designed and configured to withstand attacks. In the corporate environment, we have a bastion host that allows ssh access with Yubikey. In other words, ssh login will not work when malware or attacker has stolen your passphrase and ssh keys as they can not insert YubiKey and press the button on it to complete OTP for ssh keys. In both cases, you need to insert your YubiKey (or any FIDO2 compatible hardware key) into a USB port and complete the authentication. To avoid this mess, we can protect our ssh keys stored on local dev/desktop machines using physical security keys such as YubiKey. If your keys are stolen, an attacker can get access to all of your cloud servers, including backup servers. Unfortunately, you are not protecting ssh keys stored on a local desktop or dev machine at $HOME/.ssh/ directory. Once copied, you can now login to those servers without a password as long as ssh keys are matched.

Then you copy your public ssh key to a remote cloud server. For example, say you have a server at Linode or AWS. All Linux and Unix servers are managed manually or by automation tools such as Ansible using ssh.

Yubikey 4 fido2