Webhostinghub never told me how the other accounts got hacked the same way mine did. They said that a new user was added through the database tables and then then user signed on or had a script that signed on and then updated the php files on all 6 of my websites.
See the Wordpress post about the same issue that came from the same ip address that hacked my websites: http://wordpress.org/support/topic/new-administrator-added-ip-from-slovakia?replies=4.
I don't know how to protect against attacks to my tables but if they signed in after a new user was added then putting multiple sign-ons can help. If you had 3 different sign-ons who in the world can successfully figure out 3 different passwords in order to get to the dashboard?