an interruption in an authorized user's access to a computer network, typically one caused with malicious intent.
The most common type of Denial of Service attack involves flooding the target resource with external communication requests. This overload prevents the resource from responding to legitimate traffic, or slows its response so significantly that it is rendered effectively unavailable.
gain unauthorized access to data in a system or computer.
Cracking is the act of breaking into a computer system, often on a network. A cracker can be doing this for profit, maliciously, for some altruistic purpose or cause, or because the challenge is there.
Phishing is the attempt to acquire sensitive information such as usernames, passwords, and credit card details (and sometimes, indirectly, money) by masquerading as a trustworthy entity.
spoofing attack is a situation in which one person or program successfully masquerades as another by falsifying data and thereby gaining an illegitimate advantage.
Email spoofing is the creation of email messages with a forged sender address.
Electronic spamming is the use of electronic messaging systems to send unsolicited bulk messages (spam), especially advertising, indiscriminately
email bomb is a form of net abuse consisting of sending huge volumes of email to an address in an attempt to overflow the mailbox or overwhelm the server where the email address is hosted.
Un authorized access of a web site by hacking FTP username and password.