vBulletin is a very robust and secure application, but it still needs you to take care of some things for it to remain totally secure.
- It is passwords that secure vBulletin—make sure that all your passwords are good passwords (eight characters or greater, containing upper- and lowercase characters and numbers). Change your passwords every so often (at least 4 times a year).
- Remember too that it's not just forum access that you need to be mindful of—anyone who has access to the web server or MySQL also has access to the data the forum contains. Make sure that the passwords protecting these are robust, and if you need to give someone access (such as support personnel), change them afterwards.
- Make regular backups of your forum data ...