Computer virus Computer viruses are small software programs that are designed to spread from one computer to another and to interfere with computer operation. A virus might corrupt or delete data on your computer, use your email program to spread itself to other computers, or even erase everything on your hard disk. Computer viruses are often spread by attachments in email messages or instant messaging messages. That is why it is essential that you never open email attachments unless you know who it's from and you are expecting it. Viruses can be disguised as attachments of funny images, greeting cards, or audio and video files. Computer viruses also spread through downloads on the Internet. They can be hidden in illicit software or other files or programs you might download. Virus history In the early years floppy disks (removable media) were in fact the prevalent method used to spread viruses. Bulletin boards and online software exchange systems emerged as major channels for the spread of viruses in the late 80s. Ultimately of course, the internet in all its forms became the major source of infection. Timeline for PC Virus history is as follows: 1982 The first externally released virus is thought to be 'Elk Cloner', written by Rich Skrenta. It infected Apple DOS 3.3 computers, and spread via floppy disk. 1983 The term 'computer virus' begins to emerge. This is often credited to Fred Cohen of the University of Southern California. 1986 Early PC viruses start to appear. One of the first, emerging from Pakistan, is known as the 'Brain' and is a 'boot sector' virus (floppy disk). 1987 The first 'file' viruses begin to appear (largely affecting the essential system file command.com). 1988 The ARPANET worm, written by Robert Morris, disables approx 6,000 computers on the network. The well known (at the time) Friday the 13th virus is released in this year. The Cascade virus, thought to be the first encrypted virus, is discovered. 1989 The AIDS Trojan appears. It was fairly unique at the time because it demanded payment for removal. 1990
Anti-virus software begins to appear 1991 Norton Anti-Virus software is released by Symantec. The first widely spread polymorphic virus (one which changes its appearance as it spreads), "Tequila", is released. 1992 Well over 1,000 viruses are now thought to exist. 1994 The first major virus hoax, known as "Good Times" surfaces 1995 The first major 'Word' virus emerges, known as "Concept" 1999 The "Melissa" virus, written by David L. Smith, infects countless thousands of PCs (estimated damage = $80 million). It replicates by sending copies of itself to addresses in the Microsoft Outlook address book. The author is subsequently jailed for 20 months. 2000 In May of this year, the 'I Love You' virus, written by a Filipino student, infects millions of PCs. It is similar to "Melissa" but sends passwords back over the network. 2001 In July, the Code Red worm infects thousands of Windows NT/2000 servers, causing $2 billion in damages (estimated) 2003 In January the "Slammer" worm spreads at the fastest rate thus far, and infects hundreds of thousands of PCs. TYPES OF VIRUS Boot Virus: This one is a computer virus that usually infects the boot sector on floppy disks, hard disks, and supposedly also the other bootable media like DVD or CD. As soon as the infected PC boots the virus attacks floppies and other types of media when they are used. Boot viruses are not common these days because floppy disks are not used much. Macro Virus: Macro viruses are viruses that use another application's macro programming language to distribute themselves. They infect documents such as MS Word or MS Excel and are typically spread to other similar documents. Examples of macro viruses: Relax, Melissa. A, Bablas, O97M/Y2K. Polymorphic Viruses: A polymorphic virus not only replicates itself by creating multiple files of itself, but it also changes its digital signature every time it replicates. This makes it difficult for less sophisticated antivirus software to detect.
Memory Resident Viruses: Memory Resident Viruses reside in a computers volatile memory (RAM). They are initiated from a virus which runs on the computer and they stay in memory after its initiating program closes. Web scripting: Many websites execute complex code in order to provide interesting content. Displaying online video in your browser, for example, requires the execution of a specific code language that provides both the video itself and the player interface. Of course, this code can sometimes be exploited, making it possible for a virus to infect a computer or take actions on a computer through a website. Although malicious sites are sometimes created with purposely infected code, many such cases of virus exist because of code inserted into a site without the webmaster’s knowledge. Multipartite Virus: While some viruses are happy to spread via one method or deliver a single payload, Multipartite viruses want it all. A virus of this type may spread in multiple ways, and it may take different actions on an infected computer depending on variables, such as the operating system installed or the existence of certain files. Browser hijacker: This type of virus, which can spread itself in numerous ways including voluntary download, effectively hijacks certain browser functions, usually in the form of re-directing the user automatically to particular sites. It’s usually assumed that this tactic is designed to increase revenue from web advertisement There are a lot of such viruses, and they usually have “search” included somewhere in their description. CoolWebSearch may be the most well known example, but others are nearly as common. File infection: Perhaps the most common type of virus, the file infector takes root in a host file and then begins its operation when the file is executed. The virus may completely overwrite the file that it infects, or may only replace parts of the file, or may not replace anything but instead re-write the file so that the virus is executed rather than the program the user intended. Although called a “file virus” the definition doesn’t apply to all viruses in all files generally – for example, the macro virus below is not referred to by the file virus. Instead, the definition is usually meant to refer only to viruses which use an executable file format, such as .exe, as their host.
Worms: 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. Trojan horse: A Trojan horse program has the appearance of having a useful and desired function. While it may advertise its activity after launching, this information is not apparent to the user beforehand. Secretly the program performs other, undesired functions. 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. Antivirus To help avoid computer viruses, it's essential that you keep your computer current with the latest updates and antivirus tools, stay informed about recent threats, run your computer as a standard user (not as administrator), and that you follow a few basic rules when you surf the Internet, download files, and open attachments. Once a virus is on your computer, its type or the method it used to get there is not as important as removing it and preventing further infection. Some paid antivirus are Bit Defender offers top of the line antivirus software for desktop computers, notebooks, MAC computers and mobile devices and that's why it is the #1 antivirus in top ten antivirus list. Bit Defender Antivirus 2011 is one among the most recommended software for home and small business computers. Norton by Symantec is a pioneer in the computer security industry since years. Norton Antivirus 2011 is an improved version of the award winning antivirus software. Norton is constantly working to add features to their antivirus software to help protect computer from harmful viruses and malicious codes. Vipre Antivirus 2011 is the latest version of the award-winning fast Vipre antivirus. Just like ESET, Vipre offers fast antivirus software for home computers and home office computer users. Their software provides maximum protection while staying easy on system resources, it does not slow down the computer while scanning and/or updating definitions. Also, a great feature of their antivirus software is the Malware Detection which constantly checks your computer and while you browse or navigate over the internet. ESET Nod32 Antivirus is popular and well known for fast performance. ESET offers the most efficient antivirus software that does not slow down your computer. ESET has won many awards for providing a security solution which is not only fast but also robust. Free antivirus are Following are some of the free antivirus software
Avast! Free Antivirus is the best free antivirus software in light of recent developments. Avast has steadily been improving its detection rates over the past few years and now ranks with the some of the best. Microsoft Security Essentials is a favorite of mine with great detection rates, particularly for rootkits. Even more impressive is that Microsoft Security Essentials has very few false positives, is light on resources and is good at removal of existing malware. Avira AntiVir Personal Edition is another high quality free antivirus. AVG Anti-Virus Free Edition is also a decent choice for a free antivirus. Although this venerable antivirus has had some shaky results in detection in the recent past, it now offers a high level of protection. To counter the virus in my computer I have installed Avast! Free Antivirus.
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Anti-virus software begins to appear 1991 Norton Anti-Virus software is released by Symantec. The first widely spread polymorphic virus (one which changes its appearance as it spreads), "Tequila", is released. 1992 Well over 1,000 viruses are now thought to exist. 1994 The first major virus hoax, known as "Good Times" surfaces 1995 The first major 'Word' virus emerges, known as "Concept" 1999 The "Melissa" virus, written by David L. Smith, infects countless thousands of PCs (estimated damage = $80 million). It replicates by sending copies of itself to addresses in the Microsoft Outlook address book. The author is subsequently jailed for 20 months. 2000 In May of this year, the 'I Love You' virus, written by a Filipino student, infects millions of PCs. It is similar to "Melissa" but sends passwords back over the network. 2001 In July, the Code Red worm infects thousands of Windows NT/2000 servers, causing $2 billion in damages (estimated) 2003 In January the "Slammer" worm spreads at the fastest rate thus far, and infects hundreds of thousands of PCs. TYPES OF VIRUS Boot Virus: This one is a computer virus that usually infects the boot sector on floppy disks, hard disks, and supposedly also the other bootable media like DVD or CD. As soon as the infected PC boots the virus attacks floppies and other types of media when they are used. Boot viruses are not common these days because floppy disks are not used much. Macro Virus: Macro viruses are viruses that use another application's macro programming language to distribute themselves. They infect documents such as MS Word or MS Excel and are typically spread to other similar documents. Examples of macro viruses: Relax, Melissa. A, Bablas, O97M/Y2K. Polymorphic Viruses: A polymorphic virus not only replicates itself by creating multiple files of itself, but it also changes its digital signature every time it replicates. This makes it difficult for less sophisticated antivirus software to detect.
Memory Resident Viruses: Memory Resident Viruses reside in a computers volatile memory (RAM). They are initiated from a virus which runs on the computer and they stay in memory after its initiating program closes. Web scripting: Many websites execute complex code in order to provide interesting content. Displaying online video in your browser, for example, requires the execution of a specific code language that provides both the video itself and the player interface. Of course, this code can sometimes be exploited, making it possible for a virus to infect a computer or take actions on a computer through a website. Although malicious sites are sometimes created with purposely infected code, many such cases of virus exist because of code inserted into a site without the webmaster’s knowledge. Multipartite Virus: While some viruses are happy to spread via one method or deliver a single payload, Multipartite viruses want it all. A virus of this type may spread in multiple ways, and it may take different actions on an infected computer depending on variables, such as the operating system installed or the existence of certain files. Browser hijacker: This type of virus, which can spread itself in numerous ways including voluntary download, effectively hijacks certain browser functions, usually in the form of re-directing the user automatically to particular sites. It’s usually assumed that this tactic is designed to increase revenue from web advertisement There are a lot of such viruses, and they usually have “search” included somewhere in their description. CoolWebSearch may be the most well known example, but others are nearly as common. File infection: Perhaps the most common type of virus, the file infector takes root in a host file and then begins its operation when the file is executed. The virus may completely overwrite the file that it infects, or may only replace parts of the file, or may not replace anything but instead re-write the file so that the virus is executed rather than the program the user intended. Although called a “file virus” the definition doesn’t apply to all viruses in all files generally – for example, the macro virus below is not referred to by the file virus. Instead, the definition is usually meant to refer only to viruses which use an executable file format, such as .exe, as their host.
Worms: 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. Trojan horse: A Trojan horse program has the appearance of having a useful and desired function. While it may advertise its activity after launching, this information is not apparent to the user beforehand. Secretly the program performs other, undesired functions. 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. Antivirus To help avoid computer viruses, it's essential that you keep your computer current with the latest updates and antivirus tools, stay informed about recent threats, run your computer as a standard user (not as administrator), and that you follow a few basic rules when you surf the Internet, download files, and open attachments. Once a virus is on your computer, its type or the method it used to get there is not as important as removing it and preventing further infection. Some paid antivirus are Bit Defender offers top of the line antivirus software for desktop computers, notebooks, MAC computers and mobile devices and that's why it is the #1 antivirus in top ten antivirus list. Bit Defender Antivirus 2011 is one among the most recommended software for home and small business computers. Norton by Symantec is a pioneer in the computer security industry since years. Norton Antivirus 2011 is an improved version of the award winning antivirus software. Norton is constantly working to add features to their antivirus software to help protect computer from harmful viruses and malicious codes. Vipre Antivirus 2011 is the latest version of the award-winning fast Vipre antivirus. Just like ESET, Vipre offers fast antivirus software for home computers and home office computer users. Their software provides maximum protection while staying easy on system resources, it does not slow down the computer while scanning and/or updating definitions. Also, a great feature of their antivirus software is the Malware Detection which constantly checks your computer and while you browse or navigate over the internet. ESET Nod32 Antivirus is popular and well known for fast performance. ESET offers the most efficient antivirus software that does not slow down your computer. ESET has won many awards for providing a security solution which is not only fast but also robust. Free antivirus are Following are some of the free antivirus software
Avast! Free Antivirus is the best free antivirus software in light of recent developments. Avast has steadily been improving its detection rates over the past few years and now ranks with the some of the best. Microsoft Security Essentials is a favorite of mine with great detection rates, particularly for rootkits. Even more impressive is that Microsoft Security Essentials has very few false positives, is light on resources and is good at removal of existing malware. Avira AntiVir Personal Edition is another high quality free antivirus. AVG Anti-Virus Free Edition is also a decent choice for a free antivirus. Although this venerable antivirus has had some shaky results in detection in the recent past, it now offers a high level of protection. To counter the virus in my computer I have installed Avast! Free Antivirus.
doc_833737784.docx