4

I noticed that both of the Feitian USB/NFC U2F Security Keys I purchased on Amazon a few years ago are unfused. This means that the pre-personalization step was partially performed but not completed in a irreversible way. The devices are otherwise working normally. I have no idea if more recently purchased devices are in a similar state. The runtime on the device is JCOP.

Based on my own limited understanding, this would allow anyone with the transport key to be able to wipe and reconfigure the device. If the device is also unprotected in addition to being unfused, then it might even allow for secret extraction (again, assuming you have the transport key).

I'm curious if anyone with more knowledge on the subject could elaborate on the security implications of this condition. Specifically, I'm wondering how concerned I should be about using these security keys. If the concern is truly limited to the device being wiped by someone with the transport key, then I am not concerned since very few people would have access to that key. However, if someone with the transport key could load a patch to the runtime that allows the secrets to be exported, then that would be something I'd like to avoid using.

darco
  • 205
  • 1
  • 10
  • The info you have linked is a about JavaCard-compatible cards, while the device you linked is a u2f device (FIDO2 compliant), and it doesn‘t mention anywhere that it is JavaCard compliant. While there are potentially devices that can do both, the „fusing“ step seems specific to the JavaCard API snd isn‘t related to U2F tokens. – averell Feb 11 '20 at 06:23
  • Most U2F tokens are implemented as Javacard applets, which is an implementation detail. Through the NFC interface, I can query the underlying secure element and determine that it is an NXP secure element running JCOP, which is a specific Javacard runtime. Normally this is irrelevant because it would be locked down. And indeed this card is *almost* fully locked down: the global platform card management keys are not set to their defaults. However, pre-personalization is lower-level than global platform, which means if you have the transport key you don’t need the card management keys. – darco Feb 11 '20 at 06:42

0 Answers0