If it were me the very first thing I would do is change all passwords for site access. FTP,MYsql user database,UBBAdmin password, Site control panel etc. Including anyone that was granted access to the site that has the same type of access as you.
Also on ftp access I would ensure you don't have any old FTP accounts that can access a area they should not.
Then I would make sure you have the security patch installed that Rick stated since it should apply to your version.
Then consider upgrading UBB
