Computer fraud is a cybercrime and the act of using a computer to take or alter electronic data, or to gain unlawful use of a computer or system. In the United States, computer fraud is specifically proscribed by the Computer Fraud and Abuse Act, which criminalizes computer-related acts under federal jurisdiction.

Types of computer fraud include:

• Distributing hoax emails
• Accessing unauthorized computers
• Engaging in data mining via spyware and malware
• Hacking into computer systems to illegally access personal information, such as credit cards or Social Security numbers
• Sending computer viruses or worms with the intent to destroy or ruin another party's computer or system.

Phishing, social engineering, viruses, and DDoS attacks are fairly well-known tactics used to disrupt service or gain access to another's network, but this list is not inclusive.