Not all hackers are bad. Yes! There are good hackers called "white-hat hackers" which use the skills to improve system security for big firms or either computer antivirus software companies. The king of hackers that doing this just for fun are called "gray-hat hackers". And the ones that we never want to disturb, the ones malicious that mostly target your online activities or credit card are called "black-hat hackers".



Kevin David Mitnick is an American computer security consultant, author, and convicted hacker, best known for his high-profile 1995 arrest and five years in prison for various computer and communications-related crimes. At 12 years old, Mitnick used social engineering and dumpster diving to bypass the punch card system used in the Los Angeles bus system.

Mitnick first gained unauthorized access to a computer network in 1979, at 16 years old, when a friend gave him the phone number for the Ark, the computer system Digital Equipment Corporation. According to the U.S. Department of Justice, Mitnick gained unauthorized access to dozens of computer networks while he was a fugitive.

He used cloned cellular phones to hide his location and, among other things, copied valuable proprietary software from some of the country's largest cellular telephone and computer companies. Finally, the FBI arrested Mitnick on February 15, 1995, at his apartment in Raleigh, North Carolina, on federal offenses related to a two and half year period of computer hacking which included computer and wire fraud.



Linus Torvalds is known as one of the best hackers of all time. He rose to fame by creating Linux, the very popular Unix-based operating system. Linux is an open-source and thousands of developers have contributed to its Kernel. However, Torvalds remains the ultimate authority on what new code is incorporated into the standard Linux kernel. As of 2006, approximately two percent of the Linux kernel was written by Torvalds himself. He just aspires to be simple and have fun by making the world’s best operating system. Torvalds has received honorary doctorates from Stockholm University and the University of Helsinki.

The first prototypes of Linux were publicly released in 1991. Torvalds first encountered the GNU Project in 1991, after another Swedish-speaking computer science student, Lars Wirzenius, took him to the University of Technology to listen to free software guru Richard Stallman's speech. Torvalds used Stallman's GNU General Public License version 2 (GPLv2) for his Linux kernel.



Robert Tappan Morris is an American computer scientist and entrepreneur. He is best known for creating the Morris Worm in 1988, considered the first computer worm on the Internet. Morris was prosecuted for releasing the worm and became the first person convicted under the then-new Computer Fraud and Abuse Act. He went on to co-found the online store Viaweb, one of the first web-based applications, and later the funding firm Y Combinator—both with Paul Graham. He later joined the faculty in the Department of Electrical Engineering and Computer Science at the Massachusetts Institute of Technology, where he received tenure in 2006. He was elected to the National Academy of Engineering in 2019.

The Morris worm or Internet worm of November 2, 1988, was one of the first computer worms distributed via the Internet, and the first to gain significant mainstream media attention. It also resulted in the first felony conviction in the US under the 1986 Computer Fraud and Abuse Act. It was written by a graduate student at Cornell University, Robert Tappan Morris, and launched on November 2, 1988, from the computer systems of the Massachusetts Institute of Technology.



Gary McKinnon is a Scottish systems administrator and hacker who was accused in 2002 of perpetrating the "biggest military computer hack of all time," although McKinnon himself states that he was merely looking for evidence of free energy suppression and a cover-up of UFO activity and other technologies potentially useful to the public. On 16 October 2012, after a series of legal proceedings in Britain, Home Secretary Theresa May withdrew her extradition order to the United States.

McKinnon was accused of hacking into 97 United States military and NASA computers over a 13-month period between February 2001 and March 2002, at his girlfriend's aunt's house in London, using the name 'Solo'.



Kevin Poulsen, also known as Dark Dante, became famous for his notoriety when he took over all the telephone lines of Los Angeles radio station KIIS-FM. Kevin Lee Poulsen is also a former black-hat hacker and a contributing editor at The Daily Beast. When the Federal Bureau of Investigation started pursuing Poulsen, he went underground as a fugitive. A storage company cleared out a storage shed in Poulsen's name due to nonpayment of rent, where computer equipment was discovered which was furnished to the FBI for evidence. When he was featured on NBC's Unsolved Mysteries, the show's 1-800 telephone lines mysteriously crashed.] Poulsen was arrested in April 1991 following an investigation led in part by John McClurg.

In June 1994, Poulsen pleaded guilty to seven counts of conspiracy, fraud, and wiretapping. He was sentenced to five years in a federal penitentiary, as well as banned from using computers or the internet for 3 years after his release. He was the first American to be released from prison with a court sentence that banned him from using computers and the internet after his prison sentence. Although Chris Lamprecht was sentenced first with an internet ban on May 5, 1995, Poulsen was released from prison before Lamprecht and began serving his ban sentence earlier.



Julian Paul Assange is an Australian editor, publisher, and activist who founded WikiLeaks in 2006. WikiLeaks came to international attention in 2010 when it published a series of leaks provided by Chelsea Manning. These leaks included the Collateral Murder video (April 2010), the Afghanistan war logs (July 2010), the Iraq war logs (October 2010), and CableGate (November 2010). After the 2010 leaks, the United States government launched a criminal investigation into WikiLeaks.

In 1987, aged 16, Assange began hacking under the name Mendax. He and two others—known as "Trax" and "Prime Suspect" formed a hacking group they called "the International Subversives" He is thought to have been involved in the WANK (Worms Against Nuclear Killers) hack at NASA in 1989, but he does not acknowledge this. In September 1991, Assange was discovered hacking into the Melbourne master terminal of Nortel, a Canadian multinational telecommunications corporation.

The Australian Federal Police tapped Assange's phone line (he was using a modem), raided his home at the end of October and eventually charged him in 1994 with 31 counts of hacking and related crimes. In December 1996, he pleaded guilty to 24 charges (the others were dropped) and was ordered to pay reparations of A$2,100 and released on a good behavior bond.



Adrián Alfonso Lamo was an American threat analyst and hacker. Lamo first gained media attention for breaking into several high-profile computer networks, including those of The New York Times, Yahoo!, and Microsoft, culminating in his 2003 arrest. Lamo was best known for reporting U.S. soldier Chelsea Manning to Army criminal investigators in 2010 for leaking hundreds of thousands of sensitive U.S. government documents to WikiLeaks.

Lamo was a white hat hacker who viewed the rise of the world wide web with a mixture of excitement and alarm. He felt that others failed to see the importance of internet security in the early days of the world wide web. Lamo would break into corporate computer systems, but he never caused damage to the systems involved. Instead, he would offer to fix the security flaws free of charge, and if the flaw wasn't fixed, he would alert the media. Lamo hoped to be hired by a corporation to attempt to break in systems and test their security, a practice known as red teaming. However, by the time this practice was common, his felony conviction prevented him from being hired.