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TYPES OF COMPUTER VIRUSES
Various types of computer viruses infect systems in different ways. The most commonly known
categories of computer viruses are as follows:
Program File Virus Boot Sector Virus Macro Virus E-mail Virus
Let us learn about these in detail.
Program File Virus
A program file virus, also known as the file-infecting virus, is a type of computer virus that
infects executable files (program files such as .exe, .com, .sys, etc.) and makes them unusable or
or causing permanent damage. Running an infected program file also executes the virus code.
Once activated, the virus remains in the computer's memory and can infect additional programs.
This type of virus is sometimes referred to as a file injector. Some well-known program file
viruses include Jerusalem and Cascade.
Boot Sector Virus
The boot sector virus is one of the most destructive types of computer viruses that infects the
boot sector or the Master Boot Record (MBR) of hard disks. Once a computer system is infected
by a boot sector virus, any disk connected to the computer will also get infected. The most
commonly known boot sector viruses are Michelangelo and Stoned.
Macro Virus
A macro virus is a type of computer virus that is primarily designed to infect a specific type of
document such as Word or Excel files. When a user opens an infected document, the macro virus
activates and can execute malicious actions, often including the infection of other documents.
Sometimes, a macro virus sends itself by attaching to an e-mail and sending it to people in the
user's address book. Melissa and Bablas are the most commonly known macro viruses.
E-mail Virus
An e-mail virus is a type of computer virus that is transmitted from one computer to another
through e-mail messages. It often arrives as an infected attachment or, in some cases, through
malicious links within the email body. It gets active in the memory when a user opens an infected
e-mail or attachment. Email viruses can cause significant harm, such as deleting files, corrupting
data, or crashing systems.
HOW DOES A COMPUTER GET INFECTED WITH A VIRUS?
Computer viruses spread through several ways. Some of them are:
Using virus-infected CDs, USB drives, or other external storage devices.
Opening an infected e-mail attachment.
Downloading an infected program from the Internet, USB drives, CDs or DVDs.
Executing infected programs, which can include games, screen savers, or other applications.
Spreading through local computer networks, where a virus can move from one computer to
another via shared resources or network connections.
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