"It is a potentially damaging computer program that affects, or infects, a computer negatively by altering the way the computer works without the user's knowledge or permission." (Discovering Computers 2007: A Gateway to Information)
"A computer virus is a small software program that spreads from one computer to another computer and that interferes with computer operation. A computer virus may corrupt or delete data on a computer, use an e-mail program to spread the virus to other computers, or even delete everything on the hard disk." (http://support.microsoft.com/kb/129972)
A virus is also called a disease of a computer.
What is the cause of Computer Viruses?
Computer Viruses are caused by attaching some files or messages in emails or instant messaging. When the receiver of the file obtains that kind of file, and does not recognize the name of the sender, there is a possibility that the user's computer will have the virus if he/she entertains it. While, the receiver accepts the file and also not familiar with and immediately deletes it, his or her desktop will be free from the virus.
2. What is a WORM?
A type of a program which copies itself frequently which uses a computer network to send copies to other nodes.
"Unlike a computer virus, it does not need to attach itself to an existing program. Worms almost always cause at least some harm to the network, even if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer." (Tiernan, Ray)
A worm also has the capability to travel without any human action, unlike the virus. Due to the copying nature of worm and its capability on travelling across the networks, it will lead to too much system memory causing Web servers, network servers and individuals computer to impede responding.
3. What is a TROJAN HORSE?
This was originally came from Greek myth which is all about the Trojan war by hiding, in a huge hollow wooden horse to sneak into the fortified city of Troy. In today's generation of computer, TROJAN HORSE is defined as a malicious, security breaking program that is disguised as something benign. It is also a program that hides within or looks like a legitimate program. Unlike virus and worm, Trojan horse does not replicates itself to other computers.
4. What is a PAYLOAD?
"In the analysis of malicious software such as worms, viruses and Trojans, it refers to the software's harmful results. Examples of payloads include data destruction, messages with insulting text or spurious e-mail messages sent to a large number of people." (http://computer.yourdictionary.com/payload)
5. What is a HONEYPOT?
It is a vulnerable computer that is set-up to entice an intruder to break into.Honeypots allow the company or organization to learn how intruders are exploiting their network and also attempt to catch perpetrators who have been doing damage elsewhere on their network.
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| AT&T and YAHOO are some of the Web hosting companies which frequently uses honeypots. |
6. What is a BOTNETS?
A botnet refers to a type of bot running on an IRC network that has been created with a Trojan. When an infected computer is on the Internet the bot can then start up an IRC client and connect to an IRC server. The Trojan will also have been coded to make the bot join a certain chat room once it has connected. Multiple bots can then join in one channels and the person who has made them can now spam IRC chat rooms, launch huge numbers of Denial of Service attacks against the IRC servers causing them to go down.
7. What is SPOOFING?
It is a kind of a technique intruders use to make their network or Internet transmission appear legitimate to a victim computer or network. This was also a creation of TCP/IP packets using somebody else's IP address.
There is a common misconception, and that is what we call, "IP spoofing". This is used to hide your "IP address while surfing the net, chatting on-line and even sending e-mail. However, IP spoofing is an integral part of many network attacks that do not need to see responses (BLIND SPOOFING).
Examples of Spoofing:
a. man-in-the-middle
packet sniffs on link between the two end points, and can therefore pretend to be one end of the connection
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