[need2fart]

Try creating members have to view a thread before they can post/view forums. I use that and it prevents spam bots on my site.

Plus if it helps try using vBadvanced that stopped bots the first time but after a few days they started posting and I setup the site for them to read the rules by setting the hack "requires users to view thread before posting"

It says something like, "The administrator requires you to view a thread before you can post"

Something like that but it stopped my site from being spammed. Also add in registration captcha it helps ALOT. You can do more than captcha for more secure forum from fake bots.