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LessPass: sync-less open source password manager

lesspass.com

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Re: LessPass: sync-less open source password manager

#141

Post by JulianMorrison »

stavros wrote: post #128
grhino wrote: post #117

Earlier quoted context omitted.

These weaknesses all hold if it's discovered that lesspass is in use. How would information that the user is using lesspass leak?

The GP's points are all a bit weak, especially if this method uses a good KDF like bcrypt to generate the keys. I used SuperGenPass for a while, before switching to KeePass, and the major drawbacks I found were: 1) No way to change a password. None at all. If a site required you to make up a new password, you're out of luck (or you have to come up with a new master password every time and remember which master passwo…

In principle you could add a post-generation step that takes a description of the site's particular brand of password limitation damnfoolery and munges the output to fit. Then this profile would need to be saved somewhere so the same step could be done at password filling time.

(Still less sensible than doing this once and encrypting the result.)

Re: LessPass: sync-less open source password manager

#142

Post by atemerev »

teach wrote: post #138
atemerev wrote: post #77

OK, fine. This is one thing I can finally use. (I can't use regular storage-based password managers, as I have ADD and I will lose my password file. If it is backed up, I will lose a backup, or I will forget to update it when passwords are changed, or something else. I always screw such things up, this is absolutely inevitable, so I have to prepare. To compensate, my symbolic memory is excellent, so I just chose to m…

What's wrong with something like Lastpass?

Lastpass is something I have no control of. Leaks can happen (already have: https://blog.lastpass.com/2015/06/lastpass-security-notice.h...). More importantly, DDoS can happen, and I will be out of access to everything.

Re: LessPass: sync-less open source password manager

#143

Post by powercf »

JulianMorrison wrote: post #124
grhino wrote: post #117

Earlier quoted context omitted.

These weaknesses all hold if it's discovered that lesspass is in use. How would information that the user is using lesspass leak?

If there's any format regularity in the output, like it's in one of the PKCS message formats, that could be detected. Or if it's a fixed length that could give it away. Webcam hack. Social engineering. Binoculars. All the things. Just sweeping them up en masse and trying popular keys.

> If there's any format regularity in the output, like it's in one of the PKCS message formats, that could be detected.

After entering some junk data, and incrementing the counter field, /every/ generated password has started with one of [aeiouy], so there clearly is some regularity in the output, and I guess more if analysed in detail.

Re: LessPass: sync-less open source password manager

#144

Post by Ajedi32 »

bryanlarsen wrote: post #81
pilif wrote: post #38

How do you deal with sites whose password requirements don't match the output of LessPass? How do you handle the fact that sites want you to change your password? Yes. There's a counter field, but how do you know what site uses what version of the counter? How do you change the master password without having to change all passwords? Thing is: There's a solution for all these problems: All you have to do is actually g…

> But if you have storage for the special cases, why not just store the passwords to begin with? 1. because compromises do not give up the password 2. because storage then becomes optional, it's still usable if it's not installed on the device you're using, as long as you remember the metadata. (or keep trying different combinations until you get it, there aren't that many different combinations as long as you rarely…

#1 is true too for an encrypted password database.

Unless of course by "compromise" you meant the master password being stolen, in which case such a compromise would result in all your passwords being stolen with both types of password managers.

Re: LessPass: sync-less open source password manager

#145

Post by palant »

JulianMorrison wrote: post #102

What this seems to be, in essence: password = HMAC(key, website). Why this is bad, compared to an encrypted on-disk key store: 1. A password is now ciphertext, not a block of line noise. Every time you transmit it, you are giving away potential clues of use to an attacker. 2. The search space for possible passwords is bounded if you know the website. You are subject to key guessing attacks. If your key is short, pure…

For reference, I am the author of Easy Passwords extension which uses a very similar concept.

Your concerns are valid of course but not necessarily for PBKDF2 which is used here. As long as a significantly high number of iterations is used bruteforcing any non-trivial master password from a derived one would take so long that it becomes unrealistic. Of course, ideally you should pick a strong password as your master password (Easy Passwords actively encourages that), it would also be recommendable with an encrypted key store. LessPass uses merely 8192 iterations however, this is way too low - recommendations vary but I would consider anything below 100k insecure these days. But with a sufficient number of iterations and a strong master password your biggest worry by far should be a malware infestation on your computer - both with this approach and with an encrypted key storage.

Re: LessPass: sync-less open source password manager

#146

Post by SippinLean »

adilparvez wrote: post #40

It's great people are exploring this problem space, but so far nothing comes close to https://www.passwordstore.org/ which is just a wrapper around gpg and git. It has Android/iOS clients, as well as GUI clients. On Android I use Password Store + OpenKeychain, the UX with a YubiKey is very smooth. https://fossdroid.com/a/openkeychain.html https://fossdroid.com/a/password-store.html

Does it officially support every major browser on my desktop and phone? Anything that doesn't is still less useful to be than LastPass.

Re: LessPass: sync-less open source password manager

#148

Post by palant »

gtrubetskoy wrote: post #80
sixhobbits wrote: post #67

I really dislike the copy/marketing of this tool. OK, so it doesn't sync? How does it work? reads whole front page and all features . No sync, but access anywhere? How does it work?? *clicks the "How it works" link and reads another 5 paragraphs of "This is great. It's so simple. It works really really well. You can phone people and they'll tell you how well LessPass works". Finally, after clicking on the link and sc…

I don't have the time to figure out how it works, but I bet it uses the same principle that I presented about 3 years ago (basically there is a "master password"): http://grisha.org/blog/2013/05/31/simple-solution-to-passwor...

You better add a huge "do not use" warning to that blog post. Deriving passwords via SHA-512 or similar is a very common mistake and makes guessing your master password way too easy. I outlined the details in my blog post here:

https://palant.de/2016/04/20/security-considerations-for-pas...

No, LessPass uses PBKDF2 which is already a lot better than merely SHA-512. However, with 8192 iterations it still makes guessing the master password too easy.

Re: LessPass: sync-less open source password manager

#149

Post by problems »

obi1kenobi wrote: post #133
JulianMorrison wrote: post #102

What this seems to be, in essence: password = HMAC(key, website). Why this is bad, compared to an encrypted on-disk key store: 1. A password is now ciphertext, not a block of line noise. Every time you transmit it, you are giving away potential clues of use to an attacker. 2. The search space for possible passwords is bounded if you know the website. You are subject to key guessing attacks. If your key is short, pure…

I completely agree. What makes all of it even worse is that they only use 8192 iterations of PBKDF2, based on their blog post [1]. To counter GPU-based password cracking, 100,000+ iterations are needed as of 5 years ago [2]. [1] https://blog.lesspass.com/lesspass-how-it-works-dde742dd18a4 [2] http://stackoverflow.com/questions/6054082/recommended-of-it...

Yeah, going to Scrypt or Argon2 would mitigate a lot of the GPU-based concerns while still offering reasonable in-browser performance.

Re: LessPass: sync-less open source password manager

#150

Post by stable-point »

SippinLean wrote: post #146
adilparvez wrote: post #40

It's great people are exploring this problem space, but so far nothing comes close to https://www.passwordstore.org/ which is just a wrapper around gpg and git. It has Android/iOS clients, as well as GUI clients. On Android I use Password Store + OpenKeychain, the UX with a YubiKey is very smooth. https://fossdroid.com/a/openkeychain.html https://fossdroid.com/a/password-store.html

Does it officially support every major browser on my desktop and phone? Anything that doesn't is still less useful to be than LastPass.

I don't think it supports any browsers via plugin. You use a separate app to unlock your keychain, it places the relevant password on your clipboard and then it clears the clipboard 30s later. Very simple and therefore avoids a whole bunch of vulnerabilities other password managers (like LastPass) introduce by integrating with browser plugins.
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