The Social Engineering Toolkit (SET) is an advanced, multifunctional, and easy-to-use computer-assisted social engineering toolset created by the founders of TrustedSec (https://www.trustedsec.com/). It helps you prepare the most effective way to exploit client-side application vulnerabilities, and makes a fascinating attempt to capture the target's confidential information (for example, e-mail passwords).
Some of the most efficient and useful attack methods employed by SET include targeted phishing e-mails with a malicious file attachment, Java applet attacks, browser-based exploitation, gathering website credentials, creating infectious portable media (USB/DVD/CD), mass-mailer attacks, and other similar multi-attack web vectors. This combination of attack methods provides you with a powerful platform to utilize and select the most persuasive technique that could perform an advanced attack against a human element.
To start SET, navigate to Applications | Exploitation Tools | Social Engineering Toolkit, You could also use the terminal to load SET:
root@kali:~# setoolkit
This will execute SET and display the following options:

In our test exercise, we are going to use the curiosity of our target to open a reverse shell on the target's system. To accomplish this, we will be using SET to craft an executable and place it on a USB device. We then leave this USB device somewhere in the organization and see if someone picks it up and plugs it in.
During this attack, we are going to craft an executable that will open a reverse connection between the target machine and our testing machine. To deliver this executable, we are going to place it on a USB device with a name that will peak the curiosity of the target. Once the USB is configured, leaving it in a public area in the target organization should produce the results we need. For more information, visit the SET section at http://www.social-engineer.org/framework/general-discussion/.
The steps to perform our USB attack are as follows:





/root/.set and you will see the executable listed:
payload.exe file to the desktop and you can then load it onto a USB Device. Another trick is to change the name of the executable to something such as Executive Bonus or something that would leverage the target's curiosity. This is handy if the Autorun feature has been disabled on USB ports. Now that you have loaded up the USB, drop it in a public area inside the target enterprise or even in the parking lot.
SET is continually updated by its creators, and as such is liable to undergo drastic changes at any moment. We have only scratched the surface of this tool's capability. It is highly recommended that you continue to learn about this formidable social engineering toolset by visiting https://www.trustedsec.com/downloads/social-engineer-toolkit/; start by watching the videos that are presented on that site.