DISCLAIMER: the following article applies to the YubiKey 5 NFC model specifically (however it might work with other Yubico models too).
As I've met a couple (2 or maybe even 3) such cases during my career (YubiKey/-s not showing any signs of functioning, despite being tapped, double-tapped, pressed for a longer period of time etc.; tested on various equipment / computers, with most diverse operational systems, USB ports, hubs; driven by various drivers, tested also by using key loggers etc., etc. - I.E. after spending hours trying to get it up-and-running, only to get it finally working almost instantly, out-of-the-box, once a replacement part has been delivered by the vendor), I've decided to write an article which:
- proves that such a situation is possible (indeed :) );
- may save you quite some valuable time otherwise needed for testing.
So, apart from:
- using the Yubico's Online Verification Tool;
- testing your YubiKey via the Yubico OTP test page;
- using (various) text editors;
- relying on LEDs blinking;
- etc.;
The most direct and reliable indicator that your sample is definitely malfunctioning is (has proven to be) the following procedure:
- using the YubiKey (in any - or better yet - all of the ways described above);
- while the debug mode in the YubiKey Manager is active (the same can be easily activated by using the CLI) and;
- looking for the following content:
- touch_triggered: None
- touch_triggered: (False, False)
- touch_triggered: false