Unauthorized access to computer systems or networks means any person who secures access or attempts to secure access to a protected system.
Email bombing refers to sending a large amount of emails to the victim resulting in the victim's email account (in case of an individual) or mail server (in case of a company or an email service provider) crashing.
This kind of an attack involves altering the raw data just before it is processed by a computer and then changing it back after the processing is completed.
This attack is used for the commission of financial crimes. The key here is to make the alteration so insignificant that in a single case it would go completely unnoticed, e.g. a bank employee inserts a program into the bank's servers, that deducts a small amount of money (say Rs.5 a month) from the account of every customer. No single account holder will probably notice this unauthorized debit, but the bank employee will make a sizable amount of money every month.
Internet time theft
This connotes the usage by an unauthorized person of the Internet hours paid for by another person.
This is event dependent program. This implies that this program is created to do something only when a certain event (known as a trigger event) occurs, e.g. some viruses may be termed logic bombs because they lie dormant all through the year and become active only on a particular date (like the Chernobyl).
Virus is a program that attach itselves to a computer or a file and then circulate itselves to other files and to other computers on a network. They usually affect the data on a computer, either by altering or deleting it. Worms, unlike viruses do not need the host to attach themselves to. They merely make functional copies of themselves and do this repeatedly till they eat up all the available space on a computer's memory.
A Trojan, the program is aptly called an unauthorized program which functions from inside what seems to be an authorized program, thereby concealing what it is actually doing.
Denial of service attack
This involves flooding a computer resource with more requests than it can handle. This causes the resource (e.g. a web server) to crash thereby denying authorized users the service offered by the resource.
Distributed denial of Service attack
This is a denial of service attack wherein the perpetrators are many and are geographically widespread. It is very difficult to control such attacks.
This would include pornographic websites; pornographic magazines produced using computers (to publish and print the material) and the Internet (to download and transmit pornographic pictures, photos, writings etc.)
A spoofed email is one that appears to originate from one source but actually has been sent from another source.
Intellectual Property Crime
This includes software piracy, copyright. infringement, trademarks violations etc.
The Oxford dictionary defines stalking as ""pursuing stealthily"". Cyber stalking involves following a person's movements across the Internet by posting messages (sometimes threatening) on the bulletin boards frequented by the victim, entering the chat-rooms frequented by the victim, constantly bombarding the victim with emails etc.