The first social-engineering toolkit is a free download on social-engineer.org. Dave Kennedy, a penetration tester, created the toolkit for pen testers to simulate social engineering attacks. The SET is downloaded approximately one million times after each new release. Kennedy says it is considered by many to be the standard for companies using social engineering-based attacks as part of their pen testing. The onus is on you to do the research into the company you are pen testing, first, in order to have the best chance for success.”]
Source: https://www.csoonline.com/article/2131538/3-tips-for-using-the-social-engineering-toolkit.html