ColdCard hardware wallet

[DaveF]

What I like is they were one of the first if not the first to have a 100% open hardware public design.
Don't trust us, fine.

Here is the open source code.
Here is the list of hardware used.
Here are the schematics.
Now stop complaining and do it yourself.

Also, a clear plastic calculator looking thing is more likely to be left alone by random people.

-Dave
 

[DaveF]

https://ckbunker.com/ for the coldcard is now available on the node in a box setup offered by https://www.mynodebtc.com/
It's a full node with lightning and a ton of other apps built in that you can run on a RPi

In the last release they added beta support for ckbunker and a few other things.

Will test in the next week or so and report in.

Unless someone else here does it first.

-Dave

[dkbit98]

Will test in the next week or so and report in.

You may also want to test out Coldcard 4.0.0 Firmware Release update with some nice improvements and bug fixes
Interesting new thing is that there is Secure Coldcard Cloning, and you can just copy everything to your MicroSD card with encryption and restore it on a brand new or blank device.
List of updates includes:

- Using Bitcoin Core libsecp256k1 and optimized SHA256
- Pure-assembly AES256-CTR (faster USB)
- 24th Word Calculated
- Secure Cloning/Migrating
- Deterministic/Reproducible builds
- HSM/CKBunker Updates

Blog release with more details:
https://blog.coinkite.com/version-4.0.0-released/

It will be interesting to see how Passport hardware wallet will react and if they will use the same code in their first release.

[DaveF]

Will test in the next week or so and report in.

You may also want to test out Coldcard 4.0.0 Firmware Release update with some nice improvements and bug fixes
Interesting new thing is that there is Secure Coldcard Cloning, and you can just copy everything to your MicroSD card with encryption and restore it on a brand new or blank device.

OK didn't work, but I don't think it's a CKBunker / mynode issue. I have my mynode setup in a slightly customized VM environment and it would not see coldcard at all.
I know it works because it's fine on a standalone / non VM setup.

Going to have to tinker a bit. Going to need some time to setup a more standard mynode environment.

-Dave

[dkbit98]

Important update for Coldcard hardware wallet and not so secure Secure Elements!

@LazyNinja managed to find a flaw in architecture and bypass ColdCard MK3 security feature by opening hardware wallet, removing secure element and replacing device PIN with his own PIN code, and then he returned altered secure element and gained full access to device.
Reminder that ColdCard is using ATECC608B secure element and this attack was possible with bootloader v2.0.0, and to fix this you need to have new updated bootloader v2.0.1

Similar pin replace attack could happen for ledger and other hardware wallet devices, but he said that hardware wallets are still 100x safer then using regular PC, however they are not invincible.

Check out his thread and video procedure:
https://threadreaderapp.com/thread/1377362927729082368.html

[DaveF]

Important update for Coldcard hardware wallet and not so secure Secure Elements!

@LazyNinja managed to find a flaw in architecture and bypass ColdCard MK3 security feature by opening hardware wallet, removing secure element and replacing device PIN with his own PIN code, and then he returned altered secure element and gained full access to device.
Reminder that ColdCard is using ATECC608B secure element and this attack was possible with bootloader v2.0.0, and to fix this you need to have new updated bootloader v2.0.1

Similar pin replace attack could happen for ledger and other hardware wallet devices, but he said that hardware wallets are still 100x safer then using regular PC, however they are not invincible.

Check out his thread and video procedure:
https://threadreaderapp.com/thread/1377362927729082368.html

Well that's a oops.
There was a firmware update a couple of days ago that has this:

• Fixes security issue in v4.0.0. (3.x.x Unaffected)

Now is this fixing that or is it fixing something else?
It's a holiday weekend so lets see if they respond on Monday / Tuesday.

But as LazyNinja said it's still better then not using a hardware wallet.
Makes you wonder how the clone (passport wallet) will handle this.

-Dave

[dkbit98]

Now is this fixing that or is it fixing something else?

This update is probably not yet released for general public, and you can confirm it easily if you check the version of bootloader on your device.
I think Coldcard is working together with LazyNinja on this fix.

This is the latest release notes from March 29 on Coldcard website:

Version 4.0.1 - March 29, 2021
Fixes security issue in v4.0.0. (3.x.x Unaffected)
Known issue: formatting of SD Card does not work and leads to a crash.

Makes you wonder how the clone (passport wallet) will handle this.

Passport is still in final stages of manufacturing so they will have time to update if they are using the same bootloader, but I know they also use some code and ideas from other hardware wallets like Cobo and Trezor.

[ranochigo]

Now is this fixing that or is it fixing something else?
It's a holiday weekend so lets see if they respond on Monday / Tuesday.

This update is probably not yet released for general public, and you can confirm it easily if you check the version of bootloader on your device.
I think Coldcard is working together with LazyNinja on this fix.

Bootloader cannot be updated or modified after production. The bootloader was updated in June last year and for what it's worth, my ColdCard from Nov 2020 has ATECC608A so I believe they only changed the secure element recently. Bummer.

Anyways, I believe that they're aware of this issue. Unless you're trying to do something other than changing the firmware, I think this would be unfixable. I'm not too sure about their responsible disclosure policy but I would probably believe that a statement from them would've been released in tandem if they knew that it would have been disclosed.

[ranochigo]

As I got the vulnerability may only occur after  ColdCard has been physically in the wrong hands. If you didn’t let it out of your hands nothing can happen. IMO, any wallet  that has been in the wrong hands should not be trusted, it has to be thrown away immediately.

Basically the whole point of a hardware wallet; if the physical security fails, there should be features to prevent this types of things from happening and also why many hardware wallet manufacturers includes a secure element with their devices to minimize the risk of any physical attacks. Saying that a hardware wallet shouldn't be in someone else's hands is the premise of any security and that is not how people should solve this kind of issues.

Wouldn't be better for manufacturer to put a sealing compound over everything inside the wallet to prevent it from any type of  the "inside"-attack?  

ColdCard does put epoxy over their components but apparently it isn't enough.

[dkbit98]

As I got the vulnerability may only occur after  ColdCard has been physically in the wrong hands. If you didn’t let it out of your hands nothing can happen. IMO, any wallet  that has been in the wrong hands should not be trusted, it has to be thrown away immediately.

Well sure but someone could just take your hardware wallet, tamper with it and modify it like LazyNinja did, then return you that modified hardware wallet without you even noticing it.
Some of this scenarios have been mentioned before in topic about attack vectors for hardware wallets.

Bootloader cannot be updated or modified after production. The bootloader was updated in June last year and for what it's worth, my ColdCard from Nov 2020 has ATECC608A so I believe they only changed the secure element recently. Bummer.

I think you may be right about this, and one of the ways to mitigate this is by using good passphrase for your hardware wallet as extra layer of protection.

[ranochigo]

Well sure but someone could just take your hardware wallet, tamper with it and modify it like LazyNinja did, then return you that modified hardware wallet without you even noticing it.

Depends on the type of modifications I guess. Most of the components (AFAICT) are covered with epoxy and there is a testing for any malicious data during start up.

I think you may be right about this, and one of the ways to mitigate this is by using good passphrase for your hardware wallet as extra layer of protection.

Hmm? The attacks bypasses the PIN and would just reveal everything. I don't think Coldcard uses passphrase as an encryption, or else it would have more than a keypad, or perhaps I haven't used it enough . Exploiting the SE is probably the most crucial part of the attack and if it succeeds, then I don't see much deterrence against physical attacks.

FWIW: https://twitter.com/nvk/status/1377710160450293763.

Tons of other stuff on that Twitter but yeah, this is probably the only important one.

[dkbit98]

Hmm? The attacks bypasses the PIN and would just reveal everything. I don't think Coldcard uses passphrase as an encryption, or else it would have more than a keypad, or perhaps I haven't used it enough . Exploiting the SE is probably the most crucial part of the attack and if it succeeds, then I don't see much deterrence against physical attacks.

Coldcard is using BIP39 Passphrases and attackers can't really know if you are using one or more passphrases as they are not stored anywhere.
Sure they can try to crack it somehow but how much time they would need for this if you are not using standard 1234qwer or something stupid like that


https://coldcardwallet.com/docs/passphrase

[dkbit98]

New firmware update 4.0.2 is released for ColdCard hardware wallet with bug fixes and some interesting features and anti-wrench measure called Countdown to Brick with special PIN code similar like Trezor have, and there is now optional setting to disable USB port and make ColdCard only air-gap.
New features:

- Countdown to Brick
- Option to Disable USB
- Login Countdown Enhancements
- Display in Sats, mBTC and bits

More information: https://blog.coinkite.com/version-4.0.2-released/

[DaveF]

So, I am still having an issue using CKBunker in a visualized environment.
VirtualBox / Windows Hyper-V / VMware none work.

In a non VM world it's fine.
So the question is, has anyone else tried it?

I can open an issue on github, but I figured I would ask here 1st.

I CAN use the coldcard in a visualized environment, have for a while now with no issues. So I know it's not the hardware or the VM. But CKBunker, just does not see it.

-Dave

[DaveF]

There was a firmware update released the other day

https://coldcardwallet.com/docs/upgrade  <--Remember don't just trust my links verify for yourself.

Version 4.1.2 - July 28, 2021

    Enhancement: Shows QR code with BIP-85 derived entropy value if you press (3) while value shown on-screen. Thanks to @opennoms for idea. Works with 12/18/24-words, XPRV, privatekey and even hex cases.
    Enhancement: Offer to show QR in other places:
        Coldcard's main XPUB, in Advanced > View Identity
        Seed words, during picking process (before the quiz)
        Stored seed words: Advanced > Danger Zone > Seed Functions > View Seed Words
        TXID of just-signed transaction (64 hex digits)
        Encryption password for the system backup file (12 words)
    Enhancement: We now grind a nonce so that our signatures are always 71 bytes or shorter. This may save a byte in transaction size, and makes our signatures identical to those produced by Bitcoin Core, improving anonymity on-chain. Thanks to @craigraw for detecting this.
    Bugfix: On a blank Coldcard, after importing a seed phrase using the Seed XOR feature, the main menu was not updated to show system is "Ready To Sign".
    Bugfix: Red caution light could happen (a false positive) if a specific sequence of firmware upgrades and reboots occured in the right order. Issue could only occur once during lifetime of any particular Coldcard.

I find this the most interesting part of the update:

    Enhancement: We now grind a nonce so that our signatures are always 71 bytes or shorter. This may save a byte in transaction size, and makes our signatures identical to those produced by Bitcoin Core, improving anonymity on-chain. Thanks to @craigraw for detecting this.

Never really thought about the security implications about the fact that transactions could show that you were using a hardware wallet.
Now your TX look like you are just using the core wallet.

-Dave

[dkbit98]

Never really thought about the security implications about the fact that transactions could show that you were using a hardware wallet.
Now your TX look like you are just using the core wallet.

With all the latest law propositions in US congress it's possible that they will try to outlaw or additionally tax any transactions coming from hardware wallet, so having this enhancement is a good idea coming in right time.

I am not sure how other hardware wallets like ledger and trezor are handling this issue with signatures, and I wonder is every hardware wallet have specific signature size.

Question for you @DaveF:
Is there a way to check and confirm integrity of ColdCard hardware wallet after you purchase it and receive it?
Something similar like for other hardware wallet I wrote few days ago:
https://bitcointalk.org/index.php?topic=5351249.0

[DaveF]

Never really thought about the security implications about the fact that transactions could show that you were using a hardware wallet.
Now your TX look like you are just using the core wallet.

With all the latest law propositions in US congress it's possible that they will try to outlaw or additionally tax any transactions coming from hardware wallet, so having this enhancement is a good idea coming in right time.

I am not sure how other hardware wallets like ledger and trezor are handling this issue with signatures, and I wonder is every hardware wallet have specific signature size.

Question for you @DaveF:
Is there a way to check and confirm integrity of ColdCard hardware wallet after you purchase it and receive it?
Something similar like for other hardware wallet I wrote few days ago:
https://bitcointalk.org/index.php?topic=5351249.0

I posted in that thread yesterday: https://bitcointalk.org/index.php?topic=5351249.msg57579135#msg57579135

more or less from https://coldcardwallet.com/:

Supply Chain Protections

Getting an uncompromised product into your hands is a challenge:
Bag Number

First and foremost, we use a tamper-evident plastic bag to package the product. Each bag is unique and coded with a number. That "bag number" is written into the Coldcard's secure element as it's put into that bag. That value cannot be changed, and we ask your to verify the bag number when the Coldcard is powered-up for the first time at your location.
Clear Case

The clear plastic case on Coldcard is an important feature as well. There have been demonstrations of inserting custom hardware inside a competitor's hardware wallet to capture key-presses.
Epoxy Globs of Love

We cover the secure element, and other sensitive parts of the Coldcard with epoxy. This makes it harder to remove those chips, or change the wiring around them.

and:

GENUINE VS. CAUTION LIGHTS
To resist Evil Maids, and other sneaky people with physical access to your Coldcard, we sign our firmware with a factory key. During boot-up, the firmware's signature, and every byte of flash memory, will be verified and the appropriate Green/Red light set. Changing that light's status is actually controlled by dedicated circuitry connected directly to the Secure Element, so a rogue bit of software cannot override it. The circuit for the lights is exposed on the top surface of the product, and covered with clear epoxy, so any physical tampering by those maids will be visible as well.

I also noted there and will sty it again, nothing is going to give you security if the people looking to rob you have the time & money to target you.

And since I have not said it in a while, everyone has their own amounts of money vs security risk.
To some people leaving 0.5BTC in a hot wallet on a phone is insane since it's their entire life savings.
To others 2BTC on a phone is no big deal it's what they earned last month at their day job.

Figure out what amounts are for you and how far you want to go to protect them.

-Dave

[dkbit98]

For Dave and others who are using Coldcard hardware wallet, it's time to upgrade your firmware to latest version 4.1.3.
They fixed some bugs and increased Bitcoin Core Airgap support, but I am still disappointed they decided to switch their license from Open Source to MIT+CC.
Funny thing is they first forked original Trezor wallet code that is still Open Source, but then they switched their license when someone else (read Passport) forks their code.
Now you can only read their code, but you can't contribute anything and you can't really verify and reproduce the code.
Instead they use something like this:
https://gist.github.com/xavierfiechter/0b7323318ada8937f817606dff8fdb57

Full list of changes:

Version 4.1.3 - Sept 2, 2021

- Enhancement: support "importdescriptors" command in Bitcoin Core 0.21 so that a descriptor-based wallet is created. PSBT files are then supported natively by Core, and the resulting desktop wallet can be used for spending (ie. create PSBT via GUI) and also watching. Translation: Easy air-gap PSBT operation with Bitcoin Core!
- Enhancement: remove "m/0/0" derivations from public.txt and address explorer, since that path is obsolete and not used by any major wallets now. We can still sign PSBT files with that path, but it's an unnecessary risk to show derived addresses for a type of wallet that doesn't exist anymore.
- Enhancement: if PSBT input sections don't contain the key path information we need, show a more specific error message.
- Bugfix: a PSBT which provided the wrong pubkey (based on UTXO being spent) was not flagged as invalid, but instead we proceeded to do nothing. Now says "pubkey vs. address wrong".
- Bugfix: if asked to serialize a partially-signed transaction, we did. Now fails properly.
- Bugfix: if multiple copies of the same BIP-39 passphrase were saved to a card, the menu would not display correctly and you might not be able to select your saved value.

https://coldcardwallet.com/docs/upgrade

[DaveF]

For Dave and others who are using Coldcard hardware wallet, it's time to upgrade your firmware to latest version 4.1.3.
They fixed some bugs and increased Bitcoin Core Airgap support, but I am still disappointed they decided to switch their license from Open Source to MIT+CC.
Funny thing is they first forked original Trezor wallet code that is still Open Source, but then they switched their license when someone else (read Passport) forks their code.
Now you can only read their code, but you can't contribute anything and you can't really verify and reproduce the code.
Instead they use something like this:
https://gist.github.com/xavierfiechter/0b7323318ada8937f817606dff8fdb57

Full list of changes:

Version 4.1.3 - Sept 2, 2021

- Enhancement: support "importdescriptors" command in Bitcoin Core 0.21 so that a descriptor-based wallet is created. PSBT files are then supported natively by Core, and the resulting desktop wallet can be used for spending (ie. create PSBT via GUI) and also watching. Translation: Easy air-gap PSBT operation with Bitcoin Core!
- Enhancement: remove "m/0/0" derivations from public.txt and address explorer, since that path is obsolete and not used by any major wallets now. We can still sign PSBT files with that path, but it's an unnecessary risk to show derived addresses for a type of wallet that doesn't exist anymore.
- Enhancement: if PSBT input sections don't contain the key path information we need, show a more specific error message.
- Bugfix: a PSBT which provided the wrong pubkey (based on UTXO being spent) was not flagged as invalid, but instead we proceeded to do nothing. Now says "pubkey vs. address wrong".
- Bugfix: if asked to serialize a partially-signed transaction, we did. Now fails properly.
- Bugfix: if multiple copies of the same BIP-39 passphrase were saved to a card, the menu would not display correctly and you might not be able to select your saved value.

https://coldcardwallet.com/docs/upgrade

https://coldcardwallet.com/docs/upgrade  <--Remember don't just trust links you see in the forum verify for yourself.

I trust @dkbit98 but even I put that warning on links I post when dealing with things that have to do with wallets and such here on the forum.

As for the forking of the code and changing the license, I am beginning to kind of, sort of, a very very little bit more take their side.
When passport does something like the including of a game: https://bitcointalk.org/index.php?topic=5265233.msg57739297#msg57739297 it matters.

Although it should have no bearing on security, and probably has no effect on security. It still can cause an issue. And then, if something does happen, and even though it's no fault of the coldcard code but rather the snake game code it still gives the coldcard a mark against it. It should not, but we all know that it would.

We all know what it would look like:
'Different code, running on different hardware, with stuff added cause people to loose some money, but since it was forked from coldcard they must be insecure somewhere too'

-Dave

[dkbit98]

but even I put that warning on links I post when dealing with things that have to do with wallets and such here on the forum.

It was reference link for quoted text, because forum anti-plagiarism machine is working non-stop.

As for the forking of the code and changing the license, I am beginning to kind of, sort of, a very very little bit more take their side.

Dude, they literally used Trezor code themselves, so I guess it's just open source karma
Forking will cause no issue on Coldcard code, same way like changes in Coldcard does not affect original Trezor code.