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Digibase Security Advisory - Lastpass Compromise
Keywords: Lastpass, compromise, passwords, database, keys, rekey
DBSA ID: 2015-0006
Regarding: Lastpass Compromise
Date: 2015 06 15
Last Modified: 20150615173108 by Gung-ho Gun
Who should take note: All Current and potential Lastpass users
Rationale: Passwords may become compromised through credential leaks.
Rationale: The service is used by people for the storage of highly sensitive information that may compromise up to and including financial information.
Spread of Issue: MULTI-PLATFORM MODERATE
Rationale: The service is fairly widely used on many different classes of devices
Lastpass is a service which permits people to store sensitive information, including keys and passwords, in a central database which is unlocked with one master password for convenience. The contained information can be used for various services such as forums, blogs, website administrator logins, banking websites, purchasing/shopping sites, system administrative control interfaces, and many other sources requiring authentication.
Recently, there was a compromise which ocurred on Lastpass' network which permitted attackers to harvest the user database including email addresses, password hashes and salts (which enhance the password hash strength), as well as other information. The fact that the salts and password hashes were compromised means a chance for the user passwords to be recovered through attack techniques.
Lastpass claims that the "Vault" data was not compromised.
This is not the first time such a compromise was incurred to Lastpass as a service in this manner. The last compromise on record was 3 May 2011, where there was a striking similarity to this incident as, again, password hashes and salts were compromised.
While it is strongly advised to, at the minimum, rekey all stored private keys and change all related passwords, it is also advised to reconsider usage of services such as Lastpass due to authentication credentials being at the mercy of third party security practices which users do not have exclusive control to fully audit or otherwise restrict services. It is especially relevant and should be considered that this incident has also occurred in the past and that there is no guarantee that it cannot happen again.
Given Lastpass' claims about "Vault" data not being compromised, it is still advised to consider the data stored to be at least partially compromised and act accordingly.