The situation at LastPass may be worse than they are letting on

Adding a “password” path is actually only increasing your security by a constant factor per character because of the risk of timing attacks (unless you are sure that the path matching algorithm is secure against it now and in the future). Ideally a 2nd layer would guard against it in a multiplicative way (an entirely different with system).

Cryptographically, adding characters to the password rather than to the path is better (because it increases the search space exponentially) than adding characters to the path, which can be brute forced separately per character.

But this assumes a very perfect view of software, where there are no bugs. Once you add a risk model for bugs, then there might be small values of path length where the additional constant factor is better than the multiplicative one that you get from adding characters to your password. So your rebuttal holds, depending on the exact bug risk model you have.

I think nowadays, tailscale/wireguard is really convenient and pretty secure as a 2nd layer. I was averse to self hosting my password manager in the past due to not being comfortable having the consistent time to secure more critical applications, but I might actually move to a world where I host more critical things myself behind a VPN.

I have no idea what this has to do with this discussion, and this just comes off as an ad hominem attack. Flat earthers claim that there's an economic interest in lying to them? And you think that claim is particularly genuine or even similar to this argument?

> You don't know if this person has nothing to lose

It is possible that they have some competing business and are trying to damage LastPass, but there's absolutely no evidence of that, nor any suggestion other than to double-check your credentials and your expected security if you are a LastPass customer. So, if they do have an interest, they're doing a particularly bad job of acting within it.

> Even if they have nothing to lose that doesn't mean they are being honest.

And we're not going to reach 100% certainty of any fact through discussion on a message board. It is interesting that some people spend a lot of effort trying to ensure this obscurity gets injected into the conversation, and it suggests that their own motivations should be questioned.

All in all, on the balance of apparent probabilities, there's more reason to trust this person than not. You can attempt to assail that logic if you like, but I would appreciate it if you stuck to the facts of the argument instead of kicking up dirt.

With _random_ passwords which most LastPass users probably generated, the attacker has no way of knowing if a key resulted in a successful decryption unless they login to a particular site.

If the URLs were part of the encrypted payload though, a quick string check for “http” or “www” would tell them if a key was correct or not during their brute-force attempts. Maybe a silver lining?