A computer virus is an unwanted software program or piece of code that interferes with a computer activity. They spread through polluted files, unstable networks, and data. Once it enters the network, copies of itself can be repeated to spread from one program to another program and from one infected computer to another.
There are many antiviruses, which are applications that can help protect the machine from viruses.
It scans your system and cleans the detected viruses during the scan. Avast, Quickheal, McAfee, Kaspersky, etc. are some of the common antiviruses.
About Computer Virus
In 1983 Fred Cohen for the first time formally described the word ‘computer virus.’ Computer viruses are never a natural occurrence.
A virus binds itself to another program after reaching a device. The execution of the host program simultaneously activates the virus’s operation. It can self-replicate, inject itself into other programs or files, and then infect them.
However, not all of the computer viruses are destructive. But most of them do malicious actions in nature, such as destroying records.
Viruses propagate when the software or documents to which they are attached are moved from one device to another using a network, a disk, methods for file sharing, or through contaminated email attachments.
Many viruses use various stealth techniques to prevent anti-virus software detection of them. For example, some may infect files without raising their sizes, while others try to avoid detection by destroying the antivirus software related tasks before they can be detected. Many old viruses ensure a host file’s “last modified” date stays the same when it infects the file.
Types of Computer Virus
Computer viruses come in different forms, and the most common infections are:
- Boot Sector Virus
- Direct Action Virus
- Resident Virus
- Multipartite Virus
- Polymorphic Virus
- Overwrite Virus
- Spacefiller Virus
- File Infector Virus
Boot Sector Virus
The Boot Sector virus contaminates the master boot record, and it mostly spreads through the removable media. It is a complicated task to eliminate this virus and often needs the system to be formatted.
Direct Action Virus
The Direct-Action Virus resides dormant on a computer until the file carrying the virus is executed.
The Resident Virus embeds itself in a computer system’s memory. It is tough to distinguish the virus, and it is equally tough to remove it.
The Multipartite Virus affects and spreads in various ways. This virus infects both the program files and the system sectors.
A Polymorphic Virus is more competent in modifying its signature pattern whenever it replicates thereby rendering it hard to be detected.
As the name suggests, an Overwrite Virus spreads through emails and deletes all the files it infects.
The Spacefiller Virus is also known as Cavity Virus; it occupies the empty spaces between the codes. It does not harm the files.
Computer Virus Symptoms
The list of computer virus symptoms include:
- A slow performing computer.
- Pop-ups automatically showing up on the screen.
- Programs running on their own.
- Automatic multiplying/duplicating files.
- Presence of unknown files and applications on the computer.
- Files get deleted or corrupted.
When a user comes across any of these signs, then there are chances that the computer is virus infected. There are two ways to remove computer infection.
The first approach is do-it-yourself and the second approach is to ask for some help to get rid of the virus.