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How did LastPass master passwords get compromised?

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Re: How did LastPass master passwords get compromised?

#41

Post by md_ »

SavantIdiot wrote: post #31
wubbert wrote: post #20

This is exactly why I have never used LastPass, and have always stuck with KeePass (and KeePassXC). It is much more secure to keep all of my passwords locally than in the cloud.

This argument has never made sense to me. Keeping an encrypted password file in the cloud or locally makes no difference. There exists no computer system than can crack an AES256 encrypted document. The weaknesses are in the protocol. Storing the encrypted database in the cloud and downloading it is the same as storing it locally if the decryption protocol is performed locally. If the decryption was done in the cloud…

> There exists no computer system than can crack an AES256 encrypted document. The weaknesses are in the protocol.

Well, or in the human-chosen passphrase. There are plenty of systems that can brute force an 8-character alphanumeric password run through PBKDF2 for 100,000 rounds.

Per https://support.1password.com/pbkdf2/, that costs...about $60k.

So keeping the ciphertext safe is in fact a very reasonable precaution, especially if you have a fairly short input passphrase or are not using a ton of rounds of key stretching.

Re: How did LastPass master passwords get compromised?

#42

Post by jazzyjackson »

willis936 wrote: post #28
syvanen wrote: post #25

So this blog seems to completely ignores LastPass statement from 2021-12-28: > Our investigation has since found that some of these security alerts, which were sent to a limited subset of LastPass users, were likely triggered in error. As a result, we have adjusted our security alert systems and this issue has since been resolved. Source: https://blog.lastpass.com/2021/12/unusual-attempted-login-ac... Source2: https:…

Which is exactly what you say when facing an existential crisis. If you have a master password leak you either: 1. lie about it and the truth never comes to light 2. lie about it and get caught and the consequences are the same as if you came clean If LP suffered a master password leak then there is no benefit to telling the truth.

The consequences of “Mea Culpa, please reset your master password” seem much less existential than denying and eventually being revealed as untrustworthy.

Re: How did LastPass master passwords get compromised?

#43

Post by abarringer »

syvanen wrote: post #25

So this blog seems to completely ignores LastPass statement from 2021-12-28: > Our investigation has since found that some of these security alerts, which were sent to a limited subset of LastPass users, were likely triggered in error. As a result, we have adjusted our security alert systems and this issue has since been resolved. Source: https://blog.lastpass.com/2021/12/unusual-attempted-login-ac... Source2: https:…

"likely" "some", weasel words. Corporate marketing speak for we have no idea what happened so dream up some scenario that sounds plausible and do a press release.

Re: How did LastPass master passwords get compromised?

#44

Post by kodah »

8organicbits wrote: post #16
SloopJon wrote: post #12

The article suggests that hashing (PBKDF2) is done client-side only, and that LastPass stores this hash directly. If true, this is very bad. However, LastPass claims that PBKDF2 is also used server side: > We then take that value, and use a salt (a random string per user) and do another 100,000 rounds of hashing, and compare that to what is in our database. https://blog.lastpass.com/2015/06/lastpass-security-notice/…

I wish there was a good way to implement this sort of double hashing in web apps. Doing the extra salted hash client side ensures that the value the server sees is globally unique, even when the user is reusing passwords across sites. Unfortunately the only way I know how to implement that is to have the server send JS down to the browser that instructs it to perform the hashing. For certain types of compromises serv…

WASM will do what you want.

You can certainly have client side JS produce a hash using some other credential as the salt and then encrypt the information server side. What you really lose is the ability to do low cost comparison, because most password hashing is done deterministically. Instead you would need to retrieve the record, decrypt with the server side key, and finally compare.

Re: How did LastPass master passwords get compromised?

#45

Post by chrisfosterelli »

stingraycharles wrote: post #23
SloopJon wrote: post #12

The article suggests that hashing (PBKDF2) is done client-side only, and that LastPass stores this hash directly. If true, this is very bad. However, LastPass claims that PBKDF2 is also used server side: > We then take that value, and use a salt (a random string per user) and do another 100,000 rounds of hashing, and compare that to what is in our database. https://blog.lastpass.com/2015/06/lastpass-security-notice/…

Which to me begs the question: then why hash client-side at all? What are the threats it protects against?

This sort of scheme is common so that you do not have to share the encryption key with the provider. You derive two keys from your plaintext password: one used for authentication and one used for encrypting / decrypting the blob. This way, Lastpass can authenticate you without having to see the key to decrypt your data.

Not sure the specifics of how lastpass implements this but this is a really common approach for end-to-end encrypted apps.

Re: How did LastPass master passwords get compromised?

#46

Post by tuwtuwtuwtuw »

latortuga wrote: post #39
skarz wrote: post #30

Passwords were NOT compromised. It is hackers using existing compromised email/password combinations on brute force attempts at Lastpass. That is why your Lastpass password should be a password that you have not nor will ever use on any other site.

Plenty of folks who reported getting this email from LP, including myself, reported that they used a strong unique passphrase for LP only.

LastPass wrote that there was a bug causing these emails to be sent.

That may be correct, because several persons have reported reproducing that issue before the LastPass fix - they have written that they logged on with incorrect password while using an IP from another country and still got the email that their master password was used.

Re: How did LastPass master passwords get compromised?

#47

Post by 40four »

What are the chances these emails were actually sent out in error, like Lastpass claims? It’s not in-plausible, but I also take it with a grain of salt.

To be fair to them, I don’t think we’ve seen any reports of folks password DBs actually being compromised. Just a lot of presumed failed attempts.

If the e-mails were sent in error, then it’s all much to do about nothing. If the master passwords were actually compromised, then the system still successfully protected the clients password assets.

Re: How did LastPass master passwords get compromised?

#48

Post by benlivengood »

8organicbits wrote: post #16
SloopJon wrote: post #12

The article suggests that hashing (PBKDF2) is done client-side only, and that LastPass stores this hash directly. If true, this is very bad. However, LastPass claims that PBKDF2 is also used server side: > We then take that value, and use a salt (a random string per user) and do another 100,000 rounds of hashing, and compare that to what is in our database. https://blog.lastpass.com/2015/06/lastpass-security-notice/…

I wish there was a good way to implement this sort of double hashing in web apps. Doing the extra salted hash client side ensures that the value the server sees is globally unique, even when the user is reusing passwords across sites. Unfortunately the only way I know how to implement that is to have the server send JS down to the browser that instructs it to perform the hashing. For certain types of compromises serv…

Use client TLS certificates and let the browser handle credential management, including at-rest encryption. Or use FIDO2 hardware. There are many options available but for probably familiarity reasons the vast majority of users and browsers didn't go down that path, and neither did website owners.

Re: How did LastPass master passwords get compromised?

#49

Post by simooooo »

sunshinekitty wrote: post #32

I stopped using lastpass a couple years ago now due to ill-communicated master password leaks, ever-rising fees, and buggy UX. This seems par for the course, I can’t imagine any credible company or keen user actually using lastpass at this point.

No post body was provided.

Re: How did LastPass master passwords get compromised?

#50

Post by AnIdiotOnTheNet »

afiori wrote: post #21
wubbert wrote: post #20

This is exactly why I have never used LastPass, and have always stuck with KeePass (and KeePassXC). It is much more secure to keep all of my passwords locally than in the cloud.

The main feature that cloud solutions provide is the ability to share passwords to specific teams and users within an organization.

Even then there are locally hosted solutions like VaultWarden.
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