beavis - 2:49 pm on Feb 19, 2012 (gmt 0)
Thanks for all of the helpful responses. I definitely need to update my VB forum software and CMS.
I had a nice talk with reps from my hosting company. They told me that this type of attack is "more common than you would think." They offered me the services of an affiliated programmer who is an expert at cleaning up and locking down sites after this type of attack and I have accepted, as I don't really have enough expertise in this area to do it myself. I will make sure that the suggestions in this thread are addressed, however, and I will post any useful findings from the expert's investigation and clean up.