Computer Virus :-
These viruses are unwanted software programs or pieces of code that hinder the functioning of the computer. They spread through corrupt files, data, and unsecured networks. Once it enters your system, it copies itself to spread from one program to another and from an infected computer to another computer. So, we can say that it is a self-replicating computer program that impedes the functioning of the computer by infecting files, data, programs, etc.
There are many antivirus, which can help protect your program or computer machine from viruses. Which scans your system and cleans up the viruses found during the scan. Some of the popular antivirus are Avast, Quikil, McAfee, Kaspersky etc.
Types of Computer Virus :-
• Overwrite Computer Virus :-
It is the simplest computer virus that hosts with its own malicious code and overwrites the code of the computer system’s file. The contents of the infected file are changed partially or completely without changing it, and thus it overwrites the original program code with its faulty code and destroys it. The infected files should be deleted or replaced with a new copy.
• Append Computer Virus :-
It is a virus that shows itself by name. This virus attaches its malicious code to the end of the host program’s file. After that, it changes the header of the file in this way. It is not known if it is the same header. The header of the file redirects to the beginning of the malicious code of the append virus. Thus, this code is executed every time the program is run. However, it does not destroy the host program; Rather, it enables the code to run on its own.
• Macro Computer Virus :-
A macro virus replaces or infects any document or data file. It is embedded in a document as a macro and this virus adds its code to the document’s macros. The virus spreads when any infected documents or data files are opened on other computers.
It spreads through a software program that executes macros such as Ms Word, Ms Excel. And other documents also get infected.
The first macro virus, named the concept, spread via email with attached MS Word documents. And it infected MsWord 6.0 and Ms Word 95 documents.
• Boot Virus :-
A boot virus or boot sector virus replaces a boot sector program stored in a hard disk or any other storage device such as a floppy disk. This replaces the boot sector program with its malicious version. It infects the computer only when its use boots the computer.
Typically, it enters your system through corrupt media files, infected storage devices, and unsecured computer networks. At present, the spread of this virus is very low due to the decrease in the use of floppy disks in the operating system and the use of boot-sector security measures.
• Resident Virus :-
The resident virus resides permanently in the computer’s primary memory (RAM). When you start the computer, it activates and destroys the files and programs running on the computer.
• Multipartite Virus :-
The multipartite virus spreads and infects in many ways. This simultaneously infects both executable and executable files stored on the boot sector and hard drive. And when you turn on the computer, the program files also get infected.
• File Infector Virus :-
It is a computer virus that usually infects executable files; files with .com or .exe extensions. The virus activates when the infected file is executed. Thus it can partially or completely destroy the original file.