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Cracking encrypted LastPass vaults

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Re: Cracking encrypted LastPass vaults

#61

Post by t0mas88 »

erros wrote: post #57
t0mas88 wrote: post #48

Earlier quoted context omitted.

With 8 characters, which is way below all recommendations and using only alphanumeric + the simple special chars on the keyboard you're looking at over 7 * 10^14 possibilities. If you could do 100 million hashes per second (that seems to be possible with hardware looking at crypto stuff), the way I understand the setup you're still up against the 100100 iterations in the key derivation algorithm. So that's 7 * 10^19…

Just out of curiosity I booted up a box with 10x RTX A6000 @ 451.6 TFLOPS Speed.#1.........: 38789 H/s (11.17ms) @ Accel:128 Loops:64 Thr:64 Vec:1 Speed.#2.........: 39017 H/s (11.17ms) @ Accel:128 Loops:64 Thr:64 Vec:1 Speed.#3.........: 38894 H/s (11.16ms) @ Accel:128 Loops:64 Thr:64 Vec:1 Speed.#4.........: 39254 H/s (11.02ms) @ Accel:128 Loops:64 Thr:64 Vec:1 Speed.#5.........: 38626 H/s (11.17ms) @ Accel:128 Loo…

So you're doing 4e10 hashes per second or 390k password guesses per second. At what price per hour?

Re: Cracking encrypted LastPass vaults

#62

Post by ketzu »

massysett wrote: post #58
ketzu wrote: post #54

Earlier quoted context omitted.

My comment was only targeted against the claim that prefering easier onboarding (made by the parent comment) only means increasing profits (which probably is also true). Don't get me wrong, I am not making any "lastpass is better" point or anything, I currently think of switching to 1password, because it seems like the better solution overall. > urges users to print a backup copy I read it a few times in this thread…

The use of the secret key is part of 1Password’s operational security - a target full of worthless data is less likely to be breached: https://blog.1password.com/what-the-secret-key-does/

I used the wrong word apparently. My security vocab got worse over the years, sorry.

What I meant by it: Securing the system against breaches of, even encrypted, data.

I was trying to differentiate the security of access to the encrypted database from the security of the data inside the encrypted database, i.e., how hard is it to get it, instead of how hard it is to break once you have it.

Because I think that the security reduction discussed here (e.g., allowing weak masterpasswords) is on the "how hard is it to break it?" side, while the breach itself is on the "how hard is it got get it" side. Based on this separation, I don't think that the breach is a sign that the reduction was a price too high, because the reduction in security did not make the access easy - bad access security made that possible.

Re: Cracking encrypted LastPass vaults

#63

Post by IshKebab »

shrx wrote: post #17

Reminder to never use pixellation to obfuscate sensitive data: https://github.com/bishopfox/unredacter

That would be a lot more convincing if they had a blind demonstration. As noted in the readme, getting the CSS exactly right is both critical to making it work and extremely difficult. I'd wait until someone actually uses that software successfully in anger before we declare that you should never use pixelation.

Obviously black bars are better but sometimes you don't care that much about keeping the data secret.

Re: Cracking encrypted LastPass vaults

#64

Post by xvector »

imiric wrote: post #47
xvector wrote: post #2

Good tutorial. This is why I prefer 1Password, as it requires the secret key to be compromised in addition to the Master Password, thus providing protection against a weak master password. I've always thought it foolish to recommend solutions like LastPass and BitWarden, which don't require a secret key. It is dangerous design, prioritizing ease of onboarding over actual security. The average consumer needs an autoge…

So your more secure solution involves using... another, stronger, password? How would your mother use 1Password if she now has to remember _two_ passwords? Both LastPass and Bitwarden (and 1Password) support 2FA. This isn't a solution that will have mass adoption, but the UX is much better and more secure than using a secret key. It could even be used by non technical users, depending on the device. But password mana…

> How would your mother use 1Password if she now has to remember _two_ passwords?

She doesn't have to remember the secret key. She prints out copies and puts them somewhere safe.

> Both LastPass and Bitwarden (and 1Password) support 2FA [...] the UX is much better and more secure than using a secret key

No. Please don't make statements like this if you're not certain. 2FA confers zero benefit in a breach like this one. It is merely an access control, and doesn't provide any cryptographic benefit. Secret keys, however, make such a breach basically worthless. No amount of rainbow table usage or master password compromise will help you unless you can obtain the secret key.

Re: Cracking encrypted LastPass vaults

#65

Post by xvector »

speedgoose wrote: post #16
xvector wrote: post #5

Earlier quoted context omitted.

The problem is that most people will choose simple master passwords. By not requiring an autogenerated secret key, LastPass prioritized ease of onboarding (=increased profits) over user security, and now the average consumer will be facing the consequences.

An old Dilbert on this topic: https://dilbert.com/strip/2007-11-16

Except using a secret key doesn't increase the day to day difficulty of using the tool. In fact, it makes it easier.

Re: Cracking encrypted LastPass vaults

#66

Post by xvector »

ketzu wrote: post #62
massysett wrote: post #58

Earlier quoted context omitted.

The use of the secret key is part of 1Password’s operational security - a target full of worthless data is less likely to be breached: https://blog.1password.com/what-the-secret-key-does/

I used the wrong word apparently. My security vocab got worse over the years, sorry. What I meant by it: Securing the system against breaches of, even encrypted, data. I was trying to differentiate the security of access to the encrypted database from the security of the data inside the encrypted database, i.e., how hard is it to get it, instead of how hard it is to break once you have it. Because I think that the se…

The whole point of a password manager is that "access security" will fail at some point. That's the reason they are E2EE.

Every password manager is built with the idea that one day, the server will be hacked and the vaults will be free to download. The same goes for E2EE in general.

With this in mind, LastPass and Bitwarden's solutions are very poor and can result in most customers vaults being breached, whereas 1Password's secret key model stays strong.

Re: Cracking encrypted LastPass vaults

#67

Post by crazygringo »

IshKebab wrote: post #63
shrx wrote: post #17

Reminder to never use pixellation to obfuscate sensitive data: https://github.com/bishopfox/unredacter

That would be a lot more convincing if they had a blind demonstration. As noted in the readme, getting the CSS exactly right is both critical to making it work and extremely difficult. I'd wait until someone actually uses that software successfully in anger before we declare that you should never use pixelation. Obviously black bars are better but sometimes you don't care that much about keeping the data secret.

If it's a pixel-perfect screenshot, getting the CSS right is actually extremely easy as long as there's surrounding text. It's easy to recognize a font, easy to figure out its size, and easy to figure out the coordinates. No more than a couple minutes of trial and error.

It's only difficult if it's been resized+compressed lossily, if it's a photograph of a screen, etc. And since font rendering can be different between Windows and Mac, you might have to try it on each one for a perfect match.

Re: Cracking encrypted LastPass vaults

#68

Post by xvector »

poglet wrote: post #38
pecheny wrote: post #33

Earlier quoted context omitted.

Sorry, I don't get it. The secret key has to be stored somewhere, right? If it's on the server, the attacker gets it together with the vault. If it's on the client, then you lose your phone → you lose your passwords, which is, while secure, very risky and I wouldn't expect it from a company focused on regular customers.

It sounds like a public and private key pair, like in asymmetric encryption or public-key cryptography. The private key is stored on the client. The private key and users password are both required to authenticate against the public key stored the server. An attacker would have no success with a dictionary attack (used in the article). Even if the password was in the dictionary, the private key is still missing.

No. It's symmetric, not asymmetric. The secret key is a 128-bit key that is effectively concatenated with the master password for master key derivation.

Re: Cracking encrypted LastPass vaults

#69

Post by xvector »

nix23 wrote: post #19
xvector wrote: post #2

Good tutorial. This is why I prefer 1Password, as it requires the secret key to be compromised in addition to the Master Password, thus providing protection against a weak master password. I've always thought it foolish to recommend solutions like LastPass and BitWarden, which don't require a secret key. It is dangerous design, prioritizing ease of onboarding over actual security. The average consumer needs an autoge…

> Good tutorial. This is why I prefer 1Password, as it requires the secret key to be compromised in addition to the Master Password, thus providing protection against a weak master password. Do you know that or do you just hope they do what you think they do?

It's literally part of the vault creation flow.

Re: Cracking encrypted LastPass vaults

#70

Post by nix23 »

xvector wrote: post #69
nix23 wrote: post #19

Earlier quoted context omitted.

> Good tutorial. This is why I prefer 1Password, as it requires the secret key to be compromised in addition to the Master Password, thus providing protection against a weak master password. Do you know that or do you just hope they do what you think they do?

It's literally part of the vault creation flow.

Sure you think that, but is it the reality?
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