Are you talking about the UI or the shell password? The UI password was changed when you were installing it. If you don't remember what it was changed to there are several threads on splash that discuss it (such as https://splash.riverbed.com/message/25377#25377). If you are talking about the shell password as long as it has not been changed the default is bb!nmp4y (accounts mazu and root). Earlier versions of the software did not require password changes on configuration but that has changed in the last few releases. If you did change the shell password you will need to boot from a USB key or something along those lines.
Hope this helps!