The fancier Yubikeys have multiple functions - not just the basic U2F. One function is 'PIV' - acting as a 'smart card'. When you create or load a key, you can

The fancier Yubikeys have multiple functions - not just the basic U2F. One function is 'PIV' - acting as a 'smart card'. When you create or load a key, you can choose whether you want to require a button press or not [1]. They strongly recommend requiring a button press. No physical button press = an attacker with root can sign things at will. [1] https://docs.yubico.com/yesdk/users-manual/application-piv/pin-touch-policies.html https://docs.yubico.com/yesdk/users-manual/application-piv/p...