One step ahead of you (barely, but still!) I've already implemented that feature in the latest
developer's release ;) The idea is that you tell Admin Tools that if an IP produces X security exceptions (breach attempts) in Y amount of time, block that IP for Z amount of time. For example, if an IP produces 3 security exceptions in 1 minute we can safely assume it's a spammer, so block his miserable soul for a day.
Moreover, the new dev release's WAF integrates the Bad Behaviour filter which uses smart scanning to dodge spammers and throw them to a 403 page. On top of that, Bad Behaviour supports Project Honeypot. Just register to PH and use your key in Admin Tools configuration. On every request made to Joomla!, WAF will check the IP with PH. If it's a known spammer, email harvester or hacker it will block him. The performance penalty is really minimal (after a few hours of usage it adds less than a couple of milliseconds in the page load time) and the gains are really great.
I think you'll also like the extra security features I added on the dev release, with more to come in the very near future :)
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!