This technique allows you to use another host on the network that is idle in order to perform a port scan to another host.The main advantage of this method is that it very stealthy because the firewall log files will record the IP address of the Zombie and not our IP.
However in order to have proper results we must found hosts that are idle on the network.
Metasploit framework has a scanner that can help us to discover hosts that are idle on the network and it can be used while implementing this type of scan.
nmap -sI [Zombie IP] [Target IP]