Computer virus

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1988-03 Universal Peace virus on my Mac

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Computer virus

A computer virus is a type of malware designed to replicate itself and spread from one computer to another. It can infect computer systems by modifying other computer programs and inserting its own code. When this replication succeeds, the affected areas are then said to be "infected" with a computer virus.

Overview

Computer viruses can spread through various means, including email attachments, Internet downloads, and removable media such as USB drives. They can perform a wide range of malicious activities, including stealing personal data, logging keystrokes, and rendering the computer or certain files unusable.

History

The concept of a computer virus dates back to the early 1970s, but the first known instance of a virus in the wild was Elk Cloner, created in 1982 for the Apple II operating system. This virus spread via floppy disk and displayed a poem on infected computers. The term "virus" was first used in this context by Fred Cohen in 1983 during his academic studies.

Types of Computer Viruses

There are several types of computer viruses, each with unique characteristics and modes of operation. Some of the most common include:

• Boot Sector Virus: Infects the master boot record and spreads when the system is booted from the disk containing the virus.
• Macro Virus: Targets macros within documents and spreads when the documents are shared.
• Polymorphic Virus: Changes its code or signature patterns to evade detection by antivirus software.
• Metamorphic Virus: Completely rewrites its own code and thus, can evade detection by creating entirely new versions of itself.
• Resident Virus: Embeds itself in the memory of a computer and can execute without the need to infect a specific file.

Prevention and Removal

Preventing computer virus infections involves a combination of practices, including installing and updating antivirus software, avoiding suspicious emails and websites, and regularly updating the computer's operating system and software. Removal of a virus typically requires the use of specialized antivirus tools and may sometimes necessitate a complete system reinstall to fully eradicate the infection.

Impact

The impact of computer viruses can range from minor annoyances to significant financial loss and data breaches. High-profile virus outbreaks, such as WannaCry and NotPetya, have demonstrated the potential for widespread damage and the importance of cybersecurity measures.

See also

• Malware
• Computer worm
• Trojan horse (computing)
• Spyware
• Ransomware

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