This book targets professional penetration testers, security engineers, and analysts who possess a basic knowledge of Metasploit and wish to master the Metasploit framework, and want to develop exploit-writing skills and module development skills; it also targets those who want to achieve testing skills for testing various services. Further, it helps all those researchers who wish to add their custom functionalities to Metasploit. The transition from the intermediate-cum-basic level to the expert level, in the end, is smooth. This book discusses Ruby programming, assembly language, and attack scripting using Cortana. Therefore, a little knowledge of programming languages is required.