VIRUS
A computer virus is a computer program that can replicate itself. It can damage or infect a computer negatively by altering the way the computer works without the user’s knowledge or permission. A computer virus spreads throughout the computer and damages files and system softwares, including the operating system.
Elk Cloner was the first personal computer virus in 1981. It attached itself to the Apple DOS 3.3 operating system and spread via floppy disk.
a virus can be detected and eliminated via antiviruses. It is required though that an antivirus should be updated frequently. Most antivirus programs also protect against worms, Trojan horses and spyware.
WORM
A computer worm is a self-replicating malware computer program, which uses a computer network to send copies of itself to other nodes (usually without any user intervention). This is due to security shortcomings on the target computer. 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.
To prevent worms from damaging a PC, one can use an antivirus, anti-spyware, howerver, it should be frequently updated to ensure your computers safety. A firewall is also required.
TROJAN HORSES
Trojan Horses are programs that can also harm your computer. It hides within or appears as a legitimate program. Unlike viruses and worms, Trojan horses don’t replicate to other computers. It can make copies of itself, steal information and harm the host computer. One of the most insidious types of Trojan horse is a program that claims to get rid of viruses but instead introduces viruses onto the computer. In computer technology the term is used to hide code with one specific purpose, inside other code with a different purpose. A trojan is one of the three major types of malware.
Popular Trojans are: Netbus (by Carl-Fredrik Neikter), Subseven (by Mobman), Y3K Remote Administration Tool (by Konstantinos & Evangelos Tselentis), Back Orifice (Sir Dystic), Zeus and The Blackhole Exploit Kit
PAYLOAD
When data is sent over the Internet, each unit transmitted includes both header information and the actual data being sent. The header identifies the source and destination of the packet, while the actual data is referred to as the payload. Because header information, or overhead data, is only used in the transmission process, it is stripped from the packet when it reaches its destination. Therefore, the payload is the only data received by the destination system. 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.
HONEYPOTS
A honeypot is simply called a trap that attracts intruders to break in to a system. This computer, which appers real to an intruder, is actually separated from the company’s work. Honeypots allow a company to learn how trespassers damage their network and also to attempt on catching such intruders.
BOTNETS
botnets can be used for distributed computing purposes, such as a scientific processing, the term usually refers to multiple computers that have been infected with malicious software. A hacker may create a botnet for several different purposes, such as spreading viruses, sending e-mail spam, or crashing Web servers using a denial of service attack. Botnets can range from only a few computers to several thousand machines. While large botnets can cause the most damage, they are also easiest to locate and break apart. The unusual amount of bandwidth used by large botnets may trigger an alert at one or more ISPs, which might lead to the discovery and dismantling of the botnet.
SPOOFING
Spoofing is the term used when a computer system or computer users are deceived by typically fake identity of another user in the internet. The most common type of spoofing is through e-mail. There’s also what we call IP spoofing which involves masking the IP address of a computer. Spoofing is simply faking. Just like what happens on discussion boards where fake usernames are present. It is also present in chatrooms where some people fake their gender, age and names.
DENIAL OF SERVICE ATTACKS
A denial of service attack is an effort to make one or more computer systems unavailable. It is typically targeted at web servers, but it can also be used on mail servers, name servers, and any other type of computer system. DoS attacks are common strategy of hackers to attack a website. Since flooding a server with requests does not require any authentication, even a highly secured server is vulnerable. However, a single system is typically not capable of carrying out a successful DoS attack. Therefore, a hacker may create a botnet to control multiple computers at once.
BACKDOOR
Backdoor means access to a computer program that bypasses security mechanism. Some programmers install a backdoor in order to access programs during troubleshooting, but many hackers takes advantage of such vulnerability to gain access to information without proper authorization. However, attackers often use back doors that they detect or install themselves, as part of an exploit. In some cases, a worm is designed to take advantage of a back door created by an earlier attack. For example, Nimdagained entrance through a back door left by Code Red.
FIREWALL
A firewall limits the amount of data that can pass through a networked system so that it can protect the network from damages that unauthorized users might cause. It may be software, harware-based or both. A firewall checks data and blocks those which do not reach the security requirements. Some hardwares have built-in firewall such as routers.
References:
· Dr. Solomon's Virus Encyclopedia, 1995, ISBN 1897661002
· Anick Jesdanun (1 September 2007). "School prank starts 25 years of security woes"
· http://www.webopedia.com/TERM/F/firewall.html
· http://searchsecurity.techtarget.com
· http://searchsecurity.techtarget.com
· MALWARE Fighting Malicious Code
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