[AdmiralAsshat]

As I feared, I changed the iterations myself at some point, and they never "migrated" it to the new value. So it's above the old default, but well below the recommended number of iterations.

I don't suppose it being a non-obvious value makes it any more secure? Is an attacker brute forcing the thing likely to try obvious default values first and then give up if they don't work? Or will they simply +1 the iteration count until they hit paydirt?

[palant]

Disclaimer: I’m the author of this article.

No, the iteration count is no secret. It’s even exposed via a public API, anyone can query it if they know the email address.

[AdmiralAsshat]

Well, balls. Thanks for confirming.

[robin_reala]

…why would you even do that?

[palant]

The number of iterations is needed for login. The user enters their email address and password, and the app needs to know (before they actually log in) how many iterations to apply. There are approaches like the OPAQUE protocol which avoid having the iterations count in the open, but LastPass didn’t implement that. To their defense, OPAQUE is relatively new.

[BuildTheRobots]

[1] makes it seem like the number of rounds is included unencrypted at least on the client side binary databases. As it's sent over the wire when downloading the vault, lastpass would _have_ to have that in clear text somewhere.

[1] https://github.com/cfbao/lastpass-vault-parser