#!/bin/bash
#Script Criado por Mastah
#Alterado por Silvio Junior





  MODE="AUTO"
  #MODE="MANUAL"
  
  if [ -f /var/log/messages ] ; then
    ips=$(cat -n /var/log/messages | grep -P "(Invalid)" | grep -i sshd | awk -F" " '{ print $11}')
    attempts=1
    for ip in $ips ; do
       lastip=$ip
       if [ "$lastip" == "$ip" ] ; then
          attempts=$(expr $attempts + 1)
          if [ $attempts -ge 5 ] ; then
             echo "Brute force SSHD attack detected from $ip"
             attempts=1
             lastip=""
             blocked=$(iptables -L INPUT | grep -i $ip | grep -i DROP)
                    if [ "$blocked" ] ; then
                echo "> Ip Already Blocked. Continuing with scan"
                echo " "
             else
                if [ $MODE == "MANUAL" ] ; then
                   echo "> Do You Want to add this IP to INPUT DROP in IPTABLES rules? (y/n)"
                   read resp
                   if [ "$resp" == "y" ] ; then
                      iptables -A INPUT -s $ip -j DROP
                      echo "> IP $ip ADDED TO IPTABLES INPUT DROP ruleset"
                      echo " "
                   fi
                else
                   iptables -A INPUT -s $ip -j DROP
                   echo "> IP $ip ADDED TO IPTABLES INPUT DROP ruleset"
                   echo " "
                fi
             fi
          fi
       fi
    done
  fi