7 ms·

As per https://arstechnica.com/security/2024/09/yubikeys-are-vulnerable-to-cloning-attacks-thanks-to-newly-discovered-side-channel/ https://arstechnica.com/secu

by edent 2y ago

As per https://arstechnica.com/security/2024/09/yubikeys-are-vulnerable-to-cloning-attacks-thanks-to-newly-discovered-side-channel/ https://arstechnica.com/security/2024/09/yubikeys-are-vulner... An attacker not only needs your username and password, they also need physical access to your key. They then have to disassemble the device. If they want to give it back to you, they'll need to reassemble it. So not exactly trivial! A blob of nail-varnish over a plastic seam might be a useful canary. But this does highlight one weakness of these FIDO tokens - you have to manually maintain a list of where you've registered them. And if your token is lost or stolen, you have to manually revoke every single one.

MetaWhirledPeas 2y ago
> you have to manually maintain a list of where you've registered them For an individual, the answer there might be to limit the usage of the device to your "core" services, and rely on good password hygiene for everything else.
- lxgr 2y ago
  > rely on good password hygiene for everything else. Usually this means using a password manager, and these days many of them also support WebAuthN in a way not tied to a specific device (or platform/ecosystem).
  - davidt84 2y ago
    But if you store everything in the password manager, it's no longer two factor.
    - lxgr 2y ago
      Yes, but I don’t need/want 2FA everywhere, and it’s still a strictly better single factor than a password (since WebAuthN is resilient against server-side database leaks and phishing).
    - hypeatei 2y ago
      It's still two factors regardless of storage. Say you accidentally paste your password into the wrong field and post it on a forum. Whoever gets that still needs the second factor. Sure, if your password vault gets breached then everything is exposed but that's extremely unlikely and you have a lot of work to do in that event regardless. It's an inherent risk to using a password manager: everything is centralized so it's a valuable target.
      - davidt84 2y ago
        It is not extremely unlikely, all it takes is for you to unlock your password database on a device with some malware. The point of a second separate factor is to reduce that risk.
        duckmysick 2y ago
        If there's malware on my device, isn't it game over already? Even if I have a second factor elsewhere, the malware can access session keys to whatever service I logged into from that device, among other things.
        davidt84 2y ago
        It's certainly not good, but if you require 2FA to, say, change the email address attached to your account, or make withdrawals, or other important actions, it's not game over.
        Matumio 2y ago
        In theory. But if everything is in the password safe, the malware can just grab that and upload? And cover its traces. As opposed to patching every application/service you might use, and get access only when you use it.
- remus 2y ago
  > For an individual, the answer there might be to limit the usage of the device to your "core" services, and rely on good password hygiene for everything else. What's the advantage here over password + yubikey? Isn't password + yubikey always going to be at least as secure as password, even if the yubikey gets lost/stolen/compromised?
haroldp 2y ago
> But this does highlight one weakness of these FIDO tokens - you have to manually maintain a list of where you've registered them. FWIW, I use KeePassXC as my password manager and tag each account that uses my hardware keys, so if lost, stollen or broken, I can quickly get a list of sites from which to remove that key. I always register two keys and keep them physically separate, so I can still login in the event I lose one key.
- trueismywork 2y ago
  3 keys is where it's at. One at office, one at home, one in a bank locker that has a lot of foam.
b112 2y ago
Someone was shipping something and was using sparkle nail polish on the screw holes. They took pics and claimed the pattern was hard to duplicate. I have a nagging memory that someone demonstrated defeating it though.
aidenn0 2y ago
> If they want to give it back to you, they'll need to reassemble it. Or just give you back a different yubikey that is cloned from the original.
- acdha 2y ago
  You can’t do that without the same assembly issue. Yubikeys don’t let you generate the FIDO2 keys at all and I believe there’s a flag on x509 keys which were imported rather than generated on the device.
  - xvector 2y ago
    You would replace it with a dummy that unlocks that functionality but looks physically the same.
    - acdha 2y ago
      The “looks physically the same” part is the problem I was referring to: this attack needs a lab and some time. If they have to add reprogramming a key and weathering it to look like yours to the task it’s certainly not impossible but it moves even further into “are you at war with a nation-state?” territory where the attacks are both unlikely to be worth the cost or easier than alternatives. I’m not saying it’s not possible but 99% of normal people are really only at risk of online attacks or physical attacks which won’t be sophisticated stealth operations but more along the lines of “you’re sending me Bitcoin or I’m shooting your dog”.
      - wbl 2y ago
        Get Chinese knockoff and some coins in a tumbler
- a1o 2y ago
  This is more probable, yes
xyst 2y ago
> An attacker not only needs your username and password Usernames and passwords are leaked all the time. Many users even re-use these across multiple services. > they also need physical access to your key. With enough practice, a motivated actor could make it seamless enough that you don’t notice. Or stalk the target to find a weak point in schedule and give attacker enough time to perform EUCLEAK. We are creatures of habit after all. > And if your token is lost or stolen, you have to manually revoke every single one. I agree here. No way to easily track. I have to make a manual note for each service in password manager.
- colejohnson66 2y ago
  > Usernames and passwords are leaked all the time. Many users even re-use these across multiple services. I’d wager that people using TOTP tokens like the YubiKey are more likely to use password managers.
sowbug 2y ago
What about passkeys? I think it's possible to sign into a passkey-supporting site with just the physical credential and its PIN.
- lxgr 2y ago
  That's less related to passkeys, and more to what the site (i.e. the Relying Party in WebAuthN parlance) requires in terms of authentication security. User Verification (including PINs) is possible for non-discoverable credentials and vice versa (e.g. Bitwarden's implementation doesn't seem to support user verification at authentication time, but supports discoverable credentials). In any case, note that this particular attack seems to degrade the security of "Yubikey + PIN" from two factors (possession of the key, knowledge of the PIN) to one (possession of the key), as the PIN entry can be bypassed due to how user verification works in WebAuthN/CTAP2.
throwaway48476 2y ago
A well resourced attacker could manufacture a replacement backdoored key with your ECDSA key.
- dgoldstein0 2y ago
  A small advantage to this attack is they don't need their own manufacturing and can attack keys which are already in use. A supply chain attack of "here a pre-backdoored key I'm pretending it's perfectly secure, go use it" has no need for this exploit if you have manufacturing capability. If you don't, then intercepting new yubikeys in transit, extracting the key, and sending them along the way would also be doable with the exploit described.
jerieljan 2y ago
> But this does highlight one weakness of these FIDO tokens - you have to manually maintain a list of where you've registered them. And if your token is lost or stolen, you have to manually revoke every single one. I agree. I've been keeping track of FIDO tokens and where they work in my password manager and it's great. I honestly want to extend this idea not just to FIDO tokens, but for anything that would ever need to be revoked and replaced. So stuff like FIDO tokens, 2FA secrets, Passkeys (both already handled by my password manager), payment methods, GPG keys and such.
lallysingh 2y ago
Can they give you back a duplicate?
- laserbeam 2y ago
  Cloning a functional piece of hardware that behaves like the original yubikey doesn’t imply the clone looks and feels like the original. It sounds to me it’s like someone would make a clay copy of a key. I don’t think the attacker gets to replicate the manufacturing process to make an item the same shape and size as the original.
  - ddtaylor 2y ago
    This is inaccurate as clay is not digitally signed.
perlgeek 2y ago
I agree this is not trivial, but yubikeys are (at least sometimes) used in context with very high stakes. This includes access to "crypto" assets, but also more serious situations such as defense contractors. These are scenarios where you have well-resourced, highly motivated attackers, and this is precisely what the yubikey is supposed to defend against. So, the fob still provides fishing resistant authentication, but some of the security expectations have been subverted.
romybrielle1 2y ago
[dead]
panarky 2y ago
It's not just YubiKey. NinjaLab: "All Infineon security microcontrollers (including TPMs) that run the Infineon cryptographic library (as far as we know, any existing version) are vulnerable to the attack." - Chips in e-passports from the US, China, India, Brazil and numerous European and Asian nations - Secure enclaves in Samsung and OnePlus phones - Cryptocurrency hardware wallets like Ledger and Trezor - SIM cards - TPMs in laptops from Lenovo, Dell, and HP - EMV chips in credit and debit cards
- madars 2y ago
  Ledger uses STMicroelectronics secure elements and should not be affected by this. Trezor Safe uses Infineon OPTIGA though. See https://bitcointalk.org/index.php?topic=5304483.0 https://bitcointalk.org/index.php?topic=5304483.0 for a table with wallets and their respective microcontrollers/secure elements.
  - notarealllama 2y ago
    Nice to see a fellow enthusiast here, this is a nice point that different hardware will have different levels of related risk. But this is kind of an entire class of attack where similar paths may be able to be used on these other controllers. Don't gloss over it. On a side note, used to frequent a bar where one of the creators of Ledger also did. Was nice to spend various crypto freely!
    - rfoo 2y ago
      This is an entire class of attacks known since almost forever. So yeah, some of us already considered this so we'd like to gross over it this time.
  - pshirshov 2y ago
    Ledger literally supports key extraction as a feature and pushes hard the firmware updates. Last S firmware w/o key extraction still works, while the same X version cannot be used anymore.
- TacticalCoder 2y ago

by edent 2y ago

MetaWhirledPeas 2y ago

> you have to manually maintain a list of where you've registered them For an individual, the answer there might be to limit the usage of the device to your "core" services, and rely on good password hygiene for everything else.

lxgr 2y ago
> rely on good password hygiene for everything else. Usually this means using a password manager, and these days many of them also support WebAuthN in a way not tied to a specific device (or platform/ecosystem).
- davidt84 2y ago
  But if you store everything in the password manager, it's no longer two factor.
  - lxgr 2y ago
    Yes, but I don’t need/want 2FA everywhere, and it’s still a strictly better single factor than a password (since WebAuthN is resilient against server-side database leaks and phishing).
  - hypeatei 2y ago
    It's still two factors regardless of storage. Say you accidentally paste your password into the wrong field and post it on a forum. Whoever gets that still needs the second factor. Sure, if your password vault gets breached then everything is exposed but that's extremely unlikely and you have a lot of work to do in that event regardless. It's an inherent risk to using a password manager: everything is centralized so it's a valuable target.
    - davidt84 2y ago
      It is not extremely unlikely, all it takes is for you to unlock your password database on a device with some malware. The point of a second separate factor is to reduce that risk.
      - duckmysick 2y ago
        If there's malware on my device, isn't it game over already? Even if I have a second factor elsewhere, the malware can access session keys to whatever service I logged into from that device, among other things.
        davidt84 2y ago
        It's certainly not good, but if you require 2FA to, say, change the email address attached to your account, or make withdrawals, or other important actions, it's not game over.
        Matumio 2y ago
        In theory. But if everything is in the password safe, the malware can just grab that and upload? And cover its traces. As opposed to patching every application/service you might use, and get access only when you use it.
remus 2y ago
> For an individual, the answer there might be to limit the usage of the device to your "core" services, and rely on good password hygiene for everything else. What's the advantage here over password + yubikey? Isn't password + yubikey always going to be at least as secure as password, even if the yubikey gets lost/stolen/compromised?

haroldp 2y ago

> But this does highlight one weakness of these FIDO tokens - you have to manually maintain a list of where you've registered them. FWIW, I use KeePassXC as my password manager and tag each account that uses my hardware keys, so if lost, stollen or broken, I can quickly get a list of sites from which to remove that key. I always register two keys and keep them physically separate, so I can still login in the event I lose one key.

trueismywork 2y ago
3 keys is where it's at. One at office, one at home, one in a bank locker that has a lot of foam.

b112 2y ago

Someone was shipping something and was using sparkle nail polish on the screw holes. They took pics and claimed the pattern was hard to duplicate. I have a nagging memory that someone demonstrated defeating it though.

aidenn0 2y ago

> If they want to give it back to you, they'll need to reassemble it. Or just give you back a different yubikey that is cloned from the original.

acdha 2y ago
You can’t do that without the same assembly issue. Yubikeys don’t let you generate the FIDO2 keys at all and I believe there’s a flag on x509 keys which were imported rather than generated on the device.
- xvector 2y ago
  You would replace it with a dummy that unlocks that functionality but looks physically the same.
  - acdha 2y ago
    The “looks physically the same” part is the problem I was referring to: this attack needs a lab and some time. If they have to add reprogramming a key and weathering it to look like yours to the task it’s certainly not impossible but it moves even further into “are you at war with a nation-state?” territory where the attacks are both unlikely to be worth the cost or easier than alternatives. I’m not saying it’s not possible but 99% of normal people are really only at risk of online attacks or physical attacks which won’t be sophisticated stealth operations but more along the lines of “you’re sending me Bitcoin or I’m shooting your dog”.
    - wbl 2y ago
      Get Chinese knockoff and some coins in a tumbler
a1o 2y ago
This is more probable, yes

xyst 2y ago

> An attacker not only needs your username and password Usernames and passwords are leaked all the time. Many users even re-use these across multiple services. > they also need physical access to your key. With enough practice, a motivated actor could make it seamless enough that you don’t notice. Or stalk the target to find a weak point in schedule and give attacker enough time to perform EUCLEAK. We are creatures of habit after all. > And if your token is lost or stolen, you have to manually revoke every single one. I agree here. No way to easily track. I have to make a manual note for each service in password manager.

colejohnson66 2y ago
> Usernames and passwords are leaked all the time. Many users even re-use these across multiple services. I’d wager that people using TOTP tokens like the YubiKey are more likely to use password managers.

sowbug 2y ago

What about passkeys? I think it's possible to sign into a passkey-supporting site with just the physical credential and its PIN.

lxgr 2y ago
That's less related to passkeys, and more to what the site (i.e. the Relying Party in WebAuthN parlance) requires in terms of authentication security. User Verification (including PINs) is possible for non-discoverable credentials and vice versa (e.g. Bitwarden's implementation doesn't seem to support user verification at authentication time, but supports discoverable credentials). In any case, note that this particular attack seems to degrade the security of "Yubikey + PIN" from two factors (possession of the key, knowledge of the PIN) to one (possession of the key), as the PIN entry can be bypassed due to how user verification works in WebAuthN/CTAP2.

throwaway48476 2y ago

A well resourced attacker could manufacture a replacement backdoored key with your ECDSA key.

dgoldstein0 2y ago
A small advantage to this attack is they don't need their own manufacturing and can attack keys which are already in use. A supply chain attack of "here a pre-backdoored key I'm pretending it's perfectly secure, go use it" has no need for this exploit if you have manufacturing capability. If you don't, then intercepting new yubikeys in transit, extracting the key, and sending them along the way would also be doable with the exploit described.

jerieljan 2y ago

> But this does highlight one weakness of these FIDO tokens - you have to manually maintain a list of where you've registered them. And if your token is lost or stolen, you have to manually revoke every single one. I agree. I've been keeping track of FIDO tokens and where they work in my password manager and it's great. I honestly want to extend this idea not just to FIDO tokens, but for anything that would ever need to be revoked and replaced. So stuff like FIDO tokens, 2FA secrets, Passkeys (both already handled by my password manager), payment methods, GPG keys and such.

lallysingh 2y ago

Can they give you back a duplicate?

laserbeam 2y ago
Cloning a functional piece of hardware that behaves like the original yubikey doesn’t imply the clone looks and feels like the original. It sounds to me it’s like someone would make a clay copy of a key. I don’t think the attacker gets to replicate the manufacturing process to make an item the same shape and size as the original.
- ddtaylor 2y ago
  This is inaccurate as clay is not digitally signed.

perlgeek 2y ago

I agree this is not trivial, but yubikeys are (at least sometimes) used in context with very high stakes. This includes access to "crypto" assets, but also more serious situations such as defense contractors. These are scenarios where you have well-resourced, highly motivated attackers, and this is precisely what the yubikey is supposed to defend against. So, the fob still provides fishing resistant authentication, but some of the security expectations have been subverted.

romybrielle1 2y ago

[dead]

panarky 2y ago

It's not just YubiKey. NinjaLab: "All Infineon security microcontrollers (including TPMs) that run the Infineon cryptographic library (as far as we know, any existing version) are vulnerable to the attack." - Chips in e-passports from the US, China, India, Brazil and numerous European and Asian nations - Secure enclaves in Samsung and OnePlus phones - Cryptocurrency hardware wallets like Ledger and Trezor - SIM cards - TPMs in laptops from Lenovo, Dell, and HP - EMV chips in credit and debit cards

madars 2y ago
Ledger uses STMicroelectronics secure elements and should not be affected by this. Trezor Safe uses Infineon OPTIGA though. See https://bitcointalk.org/index.php?topic=5304483.0 https://bitcointalk.org/index.php?topic=5304483.0 for a table with wallets and their respective microcontrollers/secure elements.
- notarealllama 2y ago
  Nice to see a fellow enthusiast here, this is a nice point that different hardware will have different levels of related risk. But this is kind of an entire class of attack where similar paths may be able to be used on these other controllers. Don't gloss over it. On a side note, used to frequent a bar where one of the creators of Ledger also did. Was nice to spend various crypto freely!
  - rfoo 2y ago
    This is an entire class of attacks known since almost forever. So yeah, some of us already considered this so we'd like to gross over it this time.
- pshirshov 2y ago
  Ledger literally supports key extraction as a feature and pushes hard the firmware updates. Last S firmware w/o key extraction still works, while the same X version cannot be used anymore.
TacticalCoder 2y ago