YubiKeys are vulnerable to cloning attacks thanks to newly discovered side channel
Sophisticated attack breaks security assurances of the most popular FIDO key.
The attacker would need physical possession of the YubiKey, Security Key, or YubiHSM, knowledge of the accounts they want to target and specialized equipment to perform the necessary attack. Depending on the use case, the attacker may also require additional knowledge including username, PIN, account password, or authentication key.
The attacks require about $11,000 worth of equipment and a sophisticated understanding of electrical and cryptographic engineering. The difficulty of the attack means it would likely be carried out only by nation-states or other entities with comparable resources and then only in highly targeted scenarios. The likelihood of such an attack being used widely in the wild is extremely low.
Given this massive caveat I'd almost call that headline misleading
I would argue that if the attacker has physical possession of my yubikey, that alone means the accounts tied to it are vulnerable. While the information isn't technically wrong, I feel like that headline is misleading and this isn't as big of a deal as some would like to make it out as.
Knowledge of the account is an obvious caveat. Yubikey-based MFA is an added layer of protection for accounts, so any kind of attack against MFA assumes the attacker already knows which account to target.
It's like saying "our door lock is flawed, but the attacker would need to have knowledge of the door"
The cost and complexity is what's noteworthy and is more relevant. Although attack cost and complexity usuallu goes down with advances in tooling and research. So it may be a good idea to plan a progressive retirement of affected keys.
"Our door lock is flawed, but the attacker would need physical access to the key"
Cheaper just to beat you until you give them what they want.
The fact that this happened is surprising in general, but not super practical.
What’s the big deal? A: It affects other types of hardware which also used these crypto libraries. Some are easier to address than others.
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.
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.
