Is this because FIDO2 is flawed, the yubikey hardware design is flawed or both?
It’s due to a cryptographic library implementation in a controller used in the yubikey. It’s a third party controller, and this isn’t exclusive to yubikeys either, a shitload of other stuff uses the same controller and is likely vulnerable to the same attack.
Also, the attack requires around $10k worth of equipment and physical access to the yubikey, so while a valid attack vector, it’s also not something to get into a panic about.
Also, at least for the Yubi implementation, fixable in software, firmware >= 5.7 not vulnerable. Also not upgradeable, so replace keys if you’re worried about nation-state attacks.
I went into the article thinking I’d need to replace my keys, and after reading decided I’m a very unlikely target for this attack. My threat model doesn’t include nation states, so I’m gonna keep using my yubikeys for the foreseeable future.
I have been thinking about new hardware key(s) that can handle more than 20 passkeys, but that’s not a high priority for me right now.
It’s definitely not something a regular user should panic over. But it’s a huge deal since a lot of high security, sensitive targets also rely on the same library.
It’s pretty concerning if my backup key can just be cloned that easily. It means now I need to invest in a much better safe, which I guess was probably always a good idea.
Couldn’t you just use the yubikey like normal if you have physical access to it instead of copying it ?
In fact reading through the article it sounds like they would need to use it to extract the secret. I guess the end goal for this would be to maintain surreptitious access to something after returning the key to the target, either to build a criminal case or for espionage purposes.
Given that the vulnerability may also apply to other secure access card/devices I suppose it could also be used if a nation-state wanted to use an impostor to access secure facilities.
While the researchers have confirmed all YubiKey 5 series models can be cloned, they haven’t tested other devices using the microcontroller, such as the SLE78 made by Infineon and successor microcontrollers known as the Infineon Optiga Trust M and the Infineon Optiga TPM. The researchers suspect that any device using any of these three microcontrollers and the Infineon cryptographic library contains the same vulnerability.
Both. The cryptographic library in question is also used in other cryptographic applications too, so it’s a huge mess.
