You probably think you know what a “hacker” is, but the images portrayed in the media can be misleading. You may be thinking of a geeky-looking guy who causes peoples’ computers to get infected with viruses or cracks passwords to raid the accounts of big business. This is one kind of hacker, but in a broader sense a hacker is a person (male or female) who uses their programming skills and technical knowledge to create and modify computer software and hardware by finding their weaknesses and exploiting them. Hackers can be motivated by a number of reasons, both positive and negative. For instance, criminal hackers can create malware to commit crimes, such as stealing information and money, while other hackers are benevolent. They may work for big companies or the government in the name of protecting them from bad hackers. It helps to be familiar with these general categories of hackers: Black hat hackers This is a hacker who gains unauthorized access into a computer system or network with malicious intent. They may use computers to attack systems for profit, for fun, for political motivations, or as part of a social cause. Such penetration often involves modification and/or destruction of data, as well as distribution of computer viruses, Internet worms, and spam. White hat hackers Also known as “ethical hackers,” white hat hackers are computer security experts who specialize in penetration testing and other testing methodologies to ensure that a company’s information systems are secure. These security experts may utilize a variety of methods to carry out their tests, including social engineering tactics, use of hacking tools, and attempts to evade security to gain entry into secured areas. Gray hat hackers These are skilled hackers who sometimes act legally, sometimes in good will and sometimes not. They are a hybrid between white and black hat hackers. They usually do not hack for personal gain or have malicious intentions, but may or may not occasionally commit crimes during the course of their technological exploits. In addition to these definitions, the term “hacker” is currently used to refer to any individual who deliberately tries to compromise a computer system—regardless of objective. It may also simply refer to someone who likes to tinker around with the innards of computer systems, and it may also mean a really smart person who can solve any computer problem. So, while you may have generally thought of hackers as criminals, the term actually describes a range of people with different technical skills and motives. That’s why it would be more helpful if we used the term with descriptors, such as “white hat hacker” or “criminal hacker,” so we have a better idea to whom we are referring. After all, hackers shouldn’t have a bad reputation overall. They are usually very talented people and we need more of the good variety: white hats. Robert Siciliano is an Online Safety Expert to Intel Security . He is the author of 99 Things You Wish You Knew Before Your Mobile was Hacked! Disclosures . Join the IT Specialist Network communities on Linkedin , Twitter and Facebook to discuss some of the hottest topics and issues in information technology.