A virus is a type of malware that can infect a computer system. Viruses have two main functions:
- Destruction: Refers to the damage a computer virus can cause to a computer by deleting files or reformatting the hard drive.
- Propagation: When a virus self-replicates by placing a copy of itself into other programs across a network.
A virus’s payload delivers the destructive power and negatively impacts the confidentiality, integrity, or availability of systems or data. Common signs of computer viruses can include unwanted pop-up windows, programs that self-execute, accounts being logged out, and crashing of the device. The risk of a virus can be mitigated by installing anti-virus software, scanning on a regular basis, and backing up data.
Different Types of Viruses
There are many different types of viruses. They include:
- Boot Sector Virus: Originated when computers booted from floppy disks, now commonly distributed by USB drives. It injects itself into the boot process of the computer.
- Macro Virus: Found in programs such as Microsoft Word or Excel that host their own scripting language. These viruses can hide in file formats run by these programs such as
- Parasitic Virus: Attaches to an executable file such as a
.exeand is executed with the host file.
- Polymorphic Virus: Attempts to evade anti-virus software by altering its own code each time it’s run.
- Web Scripting Virus: Exploits vulnerabilities in browsers to install malicious software. Can be found on unsafe websites or even in malicious banner ads.
Other Types of Malware
A virus is a type of malware (malicious software). Malware is any type of software that could harm a computer system. It can make a computer perform actions without the owner’s consent or knowledge. Types of malware aside from viruses include:
- Adware: Software that spawns unwanted advertisements through popups or other means. Designed to be difficult to remove, they can severly drain resources on a system.
- Ransomware: Malware that typically encrypts all or part of the data on a system and extorts the user for money, typically cryptocurrency, to retrieve the decryption key.
- Spyware: Software that tries to monitor and gather information about a user without their knowledge or consent. It can monitor and log activity on a target system, or gather credit card and other personally identifiable information.
- Trojan Horse: A type of malware that uses code to install seemingly benign software, but it is actually used to create back doors into a system. The result is typically loss or theft of data.
- Worm: A piece of malicious software that replicates itself in order to spread to other systems. It often traverses across a network, exploiting security flaws on the target system to allow access.
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