When I installed my newest plugin Xcloner backup, it installed fine, but with its own admin account with default password "admin" and the strong message to change this ASAP.
So I tried that first thing, but my attempts to save the new password resulted in an ERROR message that sounded too painful to pursue (referencing a missing or misconfigured file...). Sorry, but I gave up on this one immediately (and did not save the message either!)
http://wordpress.org/extend/plugins/xcloner-backup-and-restore/