YubiKeys are vulnerable to cloning attacks thanks to newly discovered side channel
Sophisticated attack breaks security assurances of the most popular FIDO key.
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.
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.
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.
I spent so much on these keys wth
It doesn’t affect their newest keys, but you can’t upgrade an older key to fix it:
All YubiKeys running firmware prior to version 5.7—which was released in May and replaces the Infineon cryptolibrary with a custom one—are vulnerable. Updating key firmware on the YubiKey isn’t possible. That leaves all affected YubiKeys permanently vulnerable.
Which is why I'm now questioning why I even bought them to begin with. Any time a security flaw is found I need to spend another $50-60. Seem crazy and wasteful.
Reading the article I think most people don’t need to worry about upgrading because of this flaw; this would be a very targeted attack. And I can understand not letting the firmware upgrade; I’m pretty sure I’ve seen examples of nation-state hacks for phones that involve attackers installing an “upgraded firmware” that disables security protections to access otherwise secured info. But yeah, cost is definitely a risk with this design.
Can I roll my own with just USB and GPG?
But there's open FIDO2 sticks around. One would be SoloKeys. Then there's other competitors, though not open.
But if you mean, simple authentication via stick, sure. Or you could do your own thing, watching via udev for the MAC ID, write a file somewhere sensitive and look in your login script if it exists.
Overrated..
Despite this affecting only FIDO and barely any Yubikeys are being used for that, it's important to keep in mind that exploits and attacks get worse over time. For now it's just FIDO and requires complex hardware and practically destroying the key. I wouldn't be surprised if this exploit is just the beginning.
