#1 rule, use complex passwords that are at least 7 characters and contain number, letters, special characters and NO words from the dictionary for all accounts that have the ability to do damage :->
Within moments of your site going up hackers are already at work. Like the last poster said, it's probably not dotnetnuke, but more someone FTP'd into your server using brut force. Slamming passwords into the account name of "admin" or something similar.
#2 rule, rename all admin accounts to something other than admin, administrator, superusers etc etc. If you leave those account names alone, then a hacker needs only to figure out the second half, the password, which if you use words from the dictionary it's pretty easy.
Dunno what else to recommend other than just going through the site with a fine comb.
You could also get a 3rd party like :
Josh Martin
