Blacklisting rogue IPs

[LostBoY]

We are stablish soc monitoring in our setup and recently we noticed around 800 IPs hitting stealth and default deny rules.. i intend to blacklist these IPs by creating an incoming and outgoing deny acl at the top for these..my question is : is this the right approach to blacklist rogue IPs and is there any script or way to configure blacklisting for 800 IPs at once?