Dropbox stated that it has not been hacked, but a document posted on pastebin yesterday contains 400 Dropbox usernames and passwords and the publisher has claimed that are just a tiny fraction of a massive hack that compromises up to 7 million accounts.
These usernames and passwords were unfortunately stolen from other services and used in attempts to log in to Dropbox accounts. We’d previously detected these attacks and the vast majority of the passwords posted have been expired for some time now. All other remaining passwords have been expired as well.
My 2 Cents: change your password and enable 2 step authentication!