In November 2022, the password manager service LastPass disclosed a breach in which hackers stole password vaults containing both encrypted and plaintext data for more than 25 million users. Since then, a steady trickle of six-figure cryptocurrency heists targeting security-conscious people throughout the tech industry has led some security experts to conclude that crooks likely have succeeded at cracking open some of the stolen LastPass vaults. //

How hard would it be for well-resourced criminals to crack the master passwords securing LastPass user vaults? Perhaps the best answer to this question comes from Wladimir Palant, a security researcher and the original developer behind the Adblock Plus browser plugin.

In a December 2022 blog post, Palant explained that the crackability of a LastPass master password depends largely on two things: The complexity of the master password, and the default settings for LastPass users, which appear to have varied quite a bit based on when those users began patronizing the service.

LastPass says that since 2018 it has required a twelve-character minimum for master passwords, which the company said “greatly minimizes the ability for successful brute force password guessing.”

But Palant said while LastPass indeed improved its master password defaults in 2018, it did not force all existing customers who had master passwords of lesser lengths to pick new credentials that would satisfy the 12-character minimum.

“If you are a LastPass customer, chances are that you are completely unaware of this requirement,” Palant wrote. “That’s because LastPass didn’t ask existing customers to change their master password. I had my test account since 2018, and even today I can log in with my eight-character password without any warnings or prompts to change it.”

Palant believes LastPass also failed to upgrade many older, original customers to more secure encryption protections that were offered to newer customers over the years. One important setting in LastPass is the number of “iterations,” or how many times your master password is run through the company’s encryption routines. The more iterations, the longer it takes an offline attacker to crack your master password.

Palant noted last year that for many older LastPass users, the initial default setting for iterations was anywhere from “1” to “500.” By 2013, new LastPass customers were given 5,000 iterations by default. In February 2018, LastPass changed the default to 100,100 iterations. And very recently, it upped that again to 600,000.

Palant said the 2018 change was in response to a security bug report he filed about some users having dangerously low iterations in their LastPass settings.

“Worse yet, for reasons that are beyond me, LastPass didn’t complete this migration,” Palant wrote. “My test account is still at 5,000 iterations, as are the accounts of many other users who checked their LastPass settings. LastPass would know how many users are affected, but they aren’t telling that. In fact, it’s painfully obvious that LastPass never bothered updating users’ security settings. Not when they changed the default from 1 to 500 iterations. Not when they changed it from 500 to 5,000. Only my persistence made them consider it for their latest change. And they still failed implementing it consistently.”