Computer viruses are a type of malicious software that can cause damage to data and software on a computer. They are designed to spread across programs and systems, often attaching themselves to an executable host file. When the file is opened, the virus code executes and spreads from the document or software it is attached to via networks, drives, file-sharing programs, or infected email attachments.
There are several types of computer viruses, each with its own unique characteristics and method of attack. Some common types of computer viruses include:
- File Infectors: These are the most common type of computer virus. They attach themselves to executable files such as .exe, .com, and .sys file types.
- Boot Sector Virus: This type of virus places its code in the boot sector of a computer’s system disk. This ensures that it will be executed even before the operating system fully loads.
- Direct Action Virus: This type of virus acts as self-replicating malware that is connected to a workable file.
- Resident Virus: This type of virus infects applications as they open.
- Multipartite Virus: This type of virus can infect both boot records and program files.
- Polymorphic Virus: This type of virus can change its code to avoid detection by antivirus software.
- Overwrite Virus: This type of virus overwrites files with its own code.
It is important to keep a computer protected from these types of viruses by using antivirus software and being cautious when opening files from unknown sources.