Methods and apparatus are provided for improving resilience to forward clock attacks. A token generates a passcode from a user authentication token for presentation to an authentication server by detecting a forward clock attack; and communicating an indication of the forward clock attack to the authentication server. The generation of the user authentication passcodes is optionally suspended upon detecting the forward clock attack. The detection may be based on a comparison of a current device time of the token and a last used device time during a generation of a user authentication passcode.