In this talk, I will first review practices and weapons to fight against cyber attackers, from repeat offenders to advanced targeted attackers where threat intelligence and artificial intelligence are well expected to change the game rule. However, at the real world, there are many victims suffering from very stupid mistakes. Through a couple of examples, I will talk about TI and AI in real practices, and crowd defense - a way to integrate defense measures against both targeted and untargeted attacks, avoiding being the low hanging fruit. Finally, I will conclude with best practices around TI based crowd defense and corresponding challenges that need collective efforts.