Secure Display for FIDO Transaction Confirmation.

FIDO protocols enable online services to leverage native authenticators of end-user computing devices including fingerprint readers for authentication to replace or complement passwords. FIDO protocols also offer support for prompting a user to confirm a specific transaction. However, due to the lack of a trusted display module in most Authenticators, operating systems of user devices display transaction contents directly on the main screen. In the paper, we demonstrate an attack on FIDO transaction confirmation in which malicious applications leverage the disparity between the displayed and actual transaction contents to trick users into confirming falsified transactions. In addition, we propose a lightweight secure display mechanism for FIDO transaction confirmations on mobile devices by leveraging the ARM TrustZone technology.