[hackuser]

> I use https://lastpass.com/

I feel like it's almost certain that Lastpass is owned, as are other popular online password stores.

No security is perfect; all you can do is make it more expensive than it's worth to the attacker.

How much would it be worth to have all the passwords to every account of every Lastpass user? Does Lastpass really have the resources and skill to protect something that valuable? Is it even possible?

[mhurron]

Well as long as you 'feel' that way, it must be true.

Lastpass (supposedly) stores the encrypted password vault, never the decrypted. Decryption occurs on the users end. You would need to either have a keylogger on the target users machine to grab their master password, or compromise the software. Neither is impossible, but both are a little harder than simply break in and access Lastpass's storage.

I say supposedly because I do not know of any 3rd party verification.

[tripzilch]

> You would need to either have a keylogger on the target users machine to grab their master password, or compromise the software. Neither is impossible, but both are a little harder than simply break in and access Lastpass's storage.

That reasoning only holds if it's in fact significantly harder to compromise the software than it is to "simply break in and access Lastpass's storage". If you believe that might be possible, then the security of your password vault basically depends on the differential difficulty compared to "simply break in and compromise the login form / browser extension / update channel to make it do <whatever>".

My point is not that this would be easy, rather that if someone went as far to break in and grab the storage[0], given the sheer value of the data, the barrier to go a step further and compromise the software isn't big enough to make me go "okay well that's all right then, that might happen, but this surely won't".

The biggest difference in risk between those two scenarios is that yes some cybercriminal that is "just poking around" might easier stumble upon access and just grab the vault than to set up a compromised login form and wait--not so much more difficult but just more effort.

[0] which I agree is fair to trust Lastpass to have properly encrypted, cause if you can't trust the people you pay $12/year to keep your most sensitive data secure, then who can you trust?

[hackuser]

I didn't make that claim; why add that attitude to an otherwise pleasant conversation?

When disagreeing, please reply to the argument instead of calling names. E.g. "That is idiotic; 1 + 1 is 2, not 3" can be shortened to "1 + 1 is 2, not 3."

https://news.ycombinator.com/newsguidelines.html

[mhurron]

Yes you did make that claim. You said that you feel there is a high likelihood that lastpass is compromised. You have no evidence or proof of this, just a gut feeling presented as some sort of fact or 'just asking questions.'

"I feel like it's almost certain that Lastpass is owned"

[SnacksOnAPlane]

I use LastPass, but I'm still fearful about it. It's such a rich target, and all a hacker would really have to do is to intercept when you put your decryption key in and send it off to their own server. Then they'd have access to all your accounts. They'd have to put that backdoor into the extension, but the point is, it's doable, and most people wouldn't have any way of knowing that it happened.

[mhurron]

LastPass doesn't have you send the master key to log in or decrypt, Decryption does not occur on their servers.

https://lastpass.com/support.php?cmd=showfaq&id=6926

"LastPass says they never receive my Master Password. Don’t I send it to the LastPass servers when I log in?

No, when you login to LastPass, two things are generated from your Master Password using our code discussed previously before anything is sent to the server: the password hash and the decryption key. This is all done locally.

    The password hash is sent to our servers to verify you. Once verified, we send back your encrypted Vault. We are only sent your hash, not your Master Password.
    The decryption key, which NEVER leaves your computer, is then used to decrypt your Vault once it comes back."

[tripzilch]

Well no they better not, obviously!

The point was "all a hacker would really have to do is to intercept when you put your decryption key in and send it off to their own server" (emphasis added).

However this is more about keeping the Lastpass software secure than it is about keeping the encrypted user vaults secure. The documentation you quoted really obscures this by use of the passive voice, casting the end-user somehow as an active agent deliberately doing all the encryption/hashing and sending, implying that they are in full control :) Try this on for a change:

"LastPass says they never receive my Master Password. Doesn't the LastPass Software send it to the LastPass servers when I log in?

No, when you login to LastPass, the LastPass Software generates two things when you give it your Master Password, before the LastPass Software sends anything to the server: the password hash and the decryption key. The LastPass Software does all this locally.

The LastPass Software sends your password hash to our servers to verify you. Once verified, our server sends back your encrypted Vault. The LastPass Software only sends your hash to our server, not your Master Password that you just entered into the LastPass Software.

The LastPass Software then uses this decryption key, which should NEVER leave your computer, to decrypt your Vault once it comes back."

-

The above is IMHO a much better way to word the same documentation, since it doesn't try to gloss over a rather important part of the attack surface. It's not really fair to on the one hand congratulate a user for being security-aware enough to use a password manager, but then ignore this part. Good security software documentation should proudly present the last few exposed parts of the attack surface, especially if they are minor ones, so that a user can assess the limits of their trust--there are always limits, no sense in pretending there aren't, and it's better to know them so that the user gets to decide what they're okay with.