At 12, Mitnick used social engineering to bypass the punchcard system used in the Los Angeles bus system. After a friendly bus driver told him where he could buy his own ticket punch, he could ride any bus in the greater LA area using unused transfer slips he found in the trash. Social engineering became his primary method of obtaining information, including user names and passwords and modem phone numbers.
In high school, he was introduced by "Petronix" to phone phreaking, a method of manipulating telephones, which he often used to evade long-distance charges. He also became handy with amateur radios, which he allegedly used to gain unauthorized access to the speaker systems of nearby fast food restaurants.
Mitnick gained unauthorized access to his first computer network in 1979, at 16, when a friend gave him the phone number for the Ark, the computer system Digital Equipment Corporation (DEC) used for developing their RSTS/E operating system software. He broke into DEC's computer network and copied DEC's software, a crime he was charged with and convicted of in 1988. He was sentenced to 12 months in prison followed by three years of supervised release. Near the end of his supervised release, Mitnick hacked into Pacific Bell voice mail computers. After a warrant was issued for his arrest, Mitnick fled, becoming a fugitive for two and a half years.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. Mitnick also intercepted and stole computer passwords, altered computer networks, and broke into and read private e-mail. Mitnick was apprehended in February 1995 in North Carolina. He was found with cloned cellular phones, more than 100 clone cellular phone codes, and multiple pieces of false identification.
Mitnick's criminal activities, arrest, and trial, along with the associated journalism were all controversial.
Though Mitnick has been convicted of copying software unlawfully and possession of several forged identification documents, his supporters argue that his punishment was excessive. In his 2002 book, The Art of Deception, Mitnick states that he compromised computers solely by using passwords and codes that he gained by social engineering. He claims he did not use software programs or hacking tools for cracking passwords or otherwise exploiting computer or phone security.
- journalistic impropriety by Markoff, who had covered the case for the New York Times based on rumor and government claims, while never interviewing Kevin himself.
- overzealous prosecution of Mitnick by the government
- mainstream media over-hyping Mitnick's actual crimes
- Shimomura's involvement in the matter being unclear or of dubious legality
The case against Mitnick tested the new laws that had been enacted for dealing with computer crime, and it raised public awareness of security involving networked computers. The controversy remains, however, and Mitnick is often cited today as an example of the quintessential computer criminal.Supporters of Mitnick have asserted that many of the charges against him were fraudulent and not based on actual losses.