1). Virus - an intrusive program that infects computer files by inserting in those files copies to itself . The copies are usually executed when the file is loaded into a memory,allowing them to infect still other files. Viruses often have damaging side effects--sometimes intentionally, sometimes not. For example, some viruses may destroy a computer's hard disk or take up memory space that could otherwise be used by programs.
2|). Worms - Program that propagates itself across computers,usually creating copies to itself in each computer's memory. a worm might duplicate itself in one computer so often that causes the computer to crash.the term has generally been superseded by the term virus.
3). Trojan Horse - Named after the Trojan Horse of ancient Greek history,a trojan in a network software application design to remain hidden on an installed computer. This serves malicious purposes and are therefore a form of malware , like virus .
* Malware -- short for malicious software, is software designed to disrupt computer operation, or gain unauthorized access to computer systems.
4). Payload - is a code in the worm designed to do more than spread the worm . It might delete files on a host system , encrypt files or send documents via e-mail.
5). Honeypot - a computer system on the internet that is expressly set up to attract and "trap" people who attempt to penetrate other people's computer system . For example "hacker" .
6).Botnets - also called a " zombie army " . A botnet is a large number of compromised computers that are used to generate spam,relay viruses or flood a network or Web server with excessive requests to cause it to fail .
7).Spoofing - practice of making a transmission appear to come from an authorized user . for example, in IP spoffing, a transmission contains the IP address of an authorized user in order to obtain access to a computer or network .
8). denial of services attack-assault, usually planned, that seeks to disrupt Web access .A denial of service attack overwhelms an Internet server with connection requests that cannot be completed .In so doing, it causes the server to become so busy attempting to respond to the attack that it ignores legitimate request for connections .
9). Back door - means of gaining access to a program or system by passing its security controls. Programmers often build back doors into systems under development so that they can fix bugs. If the back doors becomes known to anyone other than the programmer, or it is not removed before the software is released,it becomes a security risk.
10 ). Firewall - security system intended to protect an organization's network against external threats, such as hackers, coming from another network such as Internet b. A firewall prevents computers in the organization's network from communicating directly with computers external to the network and vice versa .
