VIRUS, WORM AND TROJAN
A virus is a program or code that replicates itself onto other files with which it comes in contact; that is, a virus can infect another program, boot sector, partition sector,or a document that supports macros, by inserting itself or attaching itself to that medium. Most viruses only replicate, though many can do damage to a computer system or a user’s data as well.
A worm is a program that makes and facilitates the distribution of copies of itself; for example, from one disk drive to another, or by copying itself using email or another transport mechanism. The worm may do damage and compromise the security of the computer. It may arrive via exploitation of a system vulnerability or by clicking on an infected e-mail.
A Trojan Horse portrays itself as something other than what it is at the point of execution. While it may advertise its activity after launching, this information is not apparent to the user beforehand. A Trojan Horse neither replicates nor copies itself, but causes damage or compromises the security of the computer. A Trojan Horse must be sent by someone or carried by another program and may arrive in the form of a joke program or software of some sort. The malicious functionality of a Trojan Horse may be anything undesirable for a computer user, including data destruction or compromising a system by providing a means for another computer to gain access, thus bypassing normal access controls.
Computer Virus
A computer virus is a computer program that can copy itself and infect a computer. A virus can spread from one computer to another when its host is taken to the target computer, for instance because a user sent it over a network of the Internet, or carried it on a removable medium such as a floppy disk, CD, DVD or USB drive. Viruses can increase their chances of spreading to other computers by infecting files on a network file system or a file system that is accessed by another computer.
Important Facts Related to Computer Virus
· The Creeper virus was first detected on ARPANET, the forerunner of the Internet, in the early 1970s.
· The Reaper Program was created to delete creeper.
· The actual term ‘virus’ was first used in David Gerrold’s 1972 novel, when HARLIE was one.
· A program called “Elk Cloner” was the first computer virus to appear “in the wild” this is, outside the single computer or lab where it was created
· It attached itself to the APPLE DOS 3.3 operating system and spread via floppy disk.
· The first PC virus in the wild a boot sector virus “Brains” created in 1986.
· With the spread of personal computer, traditional computer viruses emerged in 1980. Bulletin board-driven software sharing contributed directly to the spread of Trojan horse programs. Shareware and boot leg software were equally common vectors for viruses on BBS.
· Macro Viruses have become common since the3 mind 1990.ost of these viruses are written in the scripting languages for Microsoft Programs such as word and Excel and spread throughout Microsoft Office by infecting documents and spreadsheets.
· Viruses that spread using cross site scripting were first reported in 2002 and were academically demonstrated in 2005. There have been multiple instances of the cross site scripting viruses in the wild, exploiting websites such as My space and Yahoo.
The most popular five computer virus came into light as far as follows :
- I Love You (2000) It spreads through e-mails.
- Code Red (2001) It affects window server.
- Nimada (2001) It is the most rampant virus.
- Melissa (1999) It spreads through World Macro and e-mails.
- Sasser (2004) It spread by attaching to port 445 on the network windows system.
Antivirus Software and Other Preventive Measures
Antivirus software can destroy the viruses by finding them. The antivirus software uses two common methods in order to detect viruses.
- Using the Virus Signature Definitions list.
- By using Heuristics Algorithm
Some antivirus programs are capable of ‘On the Fly’ scanning of received e-mails along with scanning of the open files. This process is known as ‘On-Access’ scanning.
Antivirus software does not alter the efficiency of the host software for the communication of viruses. These software need to be updated regularly so that the new viruses can be detected.
The loss incurred by the viruses can also be negated by the regular backup of data on other mediums. If any data get misplaced due to this virus then we can retrack it by backup.
Five new Computer Antivirus Software are as follows:
1) Kaspersky Antivirus 2010
2) Symantec Norton Antivirus 2010
3) McAfee Antivirus Plus 2010
4) Panda Security Antivirus Pro 2010
5) Trend Micro Antivirus + Anit Spyware 2010
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