LastPass Security Notice
Posted by LastPass:
We want to notify our community that on Friday, our team discovered and blocked suspicious activity on our network. In our investigation, we have found no evidence that encrypted user vault data was taken, nor that LastPass user accounts were accessed. The investigation has shown, no entanto, that LastPass account email addresses, password reminders, server per user salts, and authentication hashes were compromised.
We are confident that our encryption measures are sufficient to protect the vast majority of users. LastPass strengthens the authentication hash with a random salt and 100,000 rounds of server-side PBKDF2-SHA256, in addition to the rounds performed client-side. This additional strengthening makes it difficult to attack the stolen hashes with any significant speed.
Apesar de tudo, we are taking additional measures to ensure that your data remains secure, and users will be notified via email. We are requiring that all users who are logging in from a new device or IP address first verify their account by email, unless you have multifactor authentication enabled. As an added precaution, we will also be prompting users to update their master password.
Because encrypted user data was not taken, you do not need to change your passwords on sites stored in your LastPass vault. Como sempre, we also recommend enabling multifactor authentication for added protection for your LastPass account.
Security and privacy are our top concerns here at LastPass. Over the years, we have been and continue to be dedicated to transparency and proactive measures to protect our users. In addition to the above steps, we’re working with the authorities and security forensic experts.
We apologize for the extra steps of verifying your account and updating your master password, but ultimately believe this will provide you better protection. Thank you for your understanding and support.
Brian Krebs, reporting on the breach, interviewed Steve Bellovin:
But by adding a unique element, or “salt,” to each user password, database administrators can massively complicate things for attackers who may have stolen the user database and rely upon automated tools to crack user passwords.
“What a salt does it makes it hard to go after a lot of passwords at once as opposed to one users’ password, because every user requires a separate guess and that separate guess is going to take a considerable amount of time,” said Steve Bellovin, a professor in computer science at Columbia University . “With a salt, even if a bunch of users have the same password, like ‘123456,’ everyone would have a different hash.”
More concerning in this particular breach, Bellovin said, is that users’ password reminders also were stolen.
“I suspect that for a significant number of people, the password reminder — in addition to the user’s email address — is going to be useful for an attacker,” he said. “But password reminders are useful for targeted attacks, not massive attacks. That means that if your password reminder or hint is not particularly revealing to someone who doesn’t know you, it probably doesn’t matter much. Except in the case of targeted phishing attacks,” which might try to leverage data known about a specific target (such as a password hint) to trick the user into giving up the answer to their password reminder.
Read more on KrebsOnSecurity.com.