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Types of Computer Viruses

In computing terminology, a ‘malicious code’ is a term used for computer viruses and programs designed to cause damage to computers. Other types of destructive PC worms are known as Internet virus including the examples like Worms and Trojans.

Outlined below is the description of different kinds of computer viruses:

Program/File Infector

Falling under the category of parasitic viruses, a program or file infector attempts to infect the files with extension code like .exe, .com, .drv, .dil, .bin, .ovl, and .sys. It gets activate along with the execution of executable file containing virus. The virus then loads itself into memory and replicates itself to other executable files when these files are opened or run.

The File Infector virus can destroy the content contained in files and cause irreversible damage to them. Some file viruses have also operated as email worm and Trojan horse.

The best way to disinfect files infected by the file virus is to delete them and restore from back up.

Macro Computer Virus

A macro computer virus is a virus written in a language built into a software application such as a word processor. For example: Microsoft Office has the macro language built into its application. This is why most of its application programs are affected by macro computer virus.

Macro viruses are generally created using the macro recorder or Visual Basic for Applications. The applications that are the most prone to this antivirus are Word Documents, Excel Spreadsheets, Power Point Presentation, and Access Database. The virus infects templates of these documents and therefore every file that the user opens gets affected. Some common macro computer viruses are Auto Exec, Auto New, Auto Open, Auto Close, and Auto Exit.

The auto macros can be disabled by using the command ‘DisableAutoMacros’ in any macro that is written. Another way to remove it is by holding down the shift key while opening a document.

Multi-Partite Virus

It behaves in the same way as other computer viruses do. As the name signifies, they are sometimes more than one type. These are hybrids and are known as multi-partite virus.

Polymorphic Viruses

It is a kind of virus which produces different but operational copies for itself. Its attack is considered to be extremely dangerous as virus detectors will not be able to detect all instances of virus attacks simultaneously. And this is one of the reasons why it is known to be strategically designed.

Stealth Viruses

A stealth virus uses different mechanisms to prevent recognition by antivirus software. It tries to escape detection either by redirecting the disk head to head to read another sector or modifying the file size shown in the Directory listing.

Classification of some viruses is not possible as they are the file type viruses which start behaving as computer worms with an activation code.

Types of Computer Viruses

In computing terminology, a ‘malicious code’ is a term used for computer viruses and programs designed to cause damage to computers. Other types of destructive PC worms are known as Internet virus including the examples like Worms and Trojans.

Outlined below is the description of different kinds of computer viruses:

Program/File Infector

Falling under the category of parasitic viruses, a program or file infector attempts to infect the files with extension code like .exe, .com, .drv, .dil, .bin, .ovl, and .sys. It gets activate along with the execution of executable file containing virus. The virus then loads itself into memory and replicates itself to other executable files when these files are opened or run.

The File Infector virus can destroy the content contained in files and cause irreversible damage to them. Some file viruses have also operated as email worm and Trojan horse.

The best way to disinfect files infected by the file virus is to delete them and restore from back up.

Macro Computer Virus

A macro computer virus is a virus written in a language built into a software application such as a word processor. For example: Microsoft Office has the macro language built into its application. This is why most of its application programs are affected by macro computer virus.

Macro viruses are generally created using the macro recorder or Visual Basic for Applications. The applications that are the most prone to this antivirus are Word Documents, Excel Spreadsheets, Power Point Presentation, and Access Database. The virus infects templates of these documents and therefore every file that the user opens gets affected. Some common macro computer viruses are Auto Exec, Auto New, Auto Open, Auto Close, and Auto Exit.

The auto macros can be disabled by using the command ‘DisableAutoMacros’ in any macro that is written. Another way to remove it is by holding down the shift key while opening a document.

Multi-Partite Virus

It behaves in the same way as other computer viruses do. As the name signifies, they are sometimes more than one type. These are hybrids and are known as multi-partite virus.

Polymorphic Viruses

It is a kind of virus which produces different but operational copies for itself. Its attack is considered to be extremely dangerous as virus detectors will not be able to detect all instances of virus attacks simultaneously. And this is one of the reasons why it is known to be strategically designed.

Stealth Viruses

A stealth virus uses different mechanisms to prevent recognition by antivirus software. It tries to escape detection either by redirecting the disk head to head to read another sector or modifying the file size shown in the Directory listing.

Classification of some viruses is not possible as they are the file type viruses which start behaving as computer worms with an activation code.

The 5 Most Common Types of Viruses

Computer viruses are those malicious programs that once they infect your computer, they will start causing mass destruction to your PC. Similar to biological viruses, they can multiply in various ways and develop from one type to another. Since there are hundreds of viruses out there, here are the five basic types of viruses that people are most likely to encounter, in order to make the identifying process easier.

• Trojan Virus
• Worms
• Macro Virus
• Boot Sector Virus
• File Infector Virus

Trojan Virus – This virus appears to be nothing more than an interesting computer program or file of a user who’s interested in collecting audio files. Once this virus enters your computer, it doesn’t reproduce, but instead makes your computer vulnerable to malicious intruders by allowing them to access and read your files. A Trojan horse must be sent by someone or carried by a 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.

Worm – A Worm is a virus program that copies and multiplies itself by using computer networks and security flaws. Worms are more complex than Trojan viruses, I should say, and usually attacks multi-user systems. It can spread over corporate networks via the circulation of emails. Once multiplied, the copied worms scan the network for further escape and will then cause errors on the network.

Macro Virus – This type of virus usually comes as part of a document or spreadsheet, more often found in an email. Many of the current macro viruses are written in this language and attached to Word documents. This capability is powerful, but allows viruses to be written and executed much more easily than by using other methods.

Boot Sector Virus – A virus which attaches itself to the first part of the hard disk that is read by the computer upon start up, which are normally spread by floppy disks. In time, they can spread to other readable disks. Booting problems and start up problems, problems with retrieving data, computer performance instability and the inability to locate hard drives are all issues that may arise due to a boot sector virus infection.

File Infector Virus – As the name indicates, this type of virus was designed to avoid detection by antivirus software by changing itself internally. Upon running a program that has been corrupted by a file infector, the virus copies the malicious code and applies it to other executable applications on the computer. Files that are the most vulnerable to this type of infection have the extensions of EXE. and .COM, though any file is capable of execution can be infected.

How to fight some of these viruses is still completely a puzzle for anti-virus makers. However, knowing a little about your enemies could be an advantage to get vital information on how to defend your computer from those threats. Read on Virus Removal Help – How to Remove Viruses Easily From Your PC? in order to become more familiar with the steps on how to remove the common types of viruses from your computer.