Has LastPass been audited?
LastPass has engaged 3rd party security firms for regular reviews of the service and does automatic nightly reviews as well. We improve our service based on those findings and have not published them to-date without an NDA in place.
There are a number of bloggers and security researchers that have done in-depth reviews of LastPass' security and attempted to demonstrate that we do what we say we do. One such blog post is: http://tinisles.blogspot.com/2010/01/should-you-trust-lastpasscom.html
Any security-related concerns or reports can be directed to the team at firstname.lastname@example.org