What is Ethical Hacking?

Ethical hacking and ethical hacker are terms used to describe hacking performed by a company or individual to help identify potential threats on a computer or network. An ethical hacker attempts to bypass system security and search for any weak points that could be exploited by malicious hackers. 
Companies hire them to gaining the trust of customers and investors by ensuring the security of their products and data. It is no big secret that any system, process, website, device, etc., can be hacked. In order to understand how the hack might happen and what the damage could be, ethical hackers must know how to think like malicious hackers and know the tools and techniques they are likely to use. It is is considered legal because the actions are used to increase the security of a computer system.