Computer viruses pose a considerable risk for users of personal computers. The emergence of viruses of various types is a big problem and need higher level of awareness of viruses by users. The variety of viruses that exist today and the strategies they use to infect and to defeat the AV is rising.Viruses can be disguised as attachments of funny images, greeting cards, or audio and video files

A computer virus is a computer program that can spread across computers and networks by making copies of itself, usually without the user‘s knowledge
Viruses have four essential characteristics to infect the system.
1. The ability to replicate itself to infect computers,
2.  it must be executed. If it cannot be executed, it is harmless. Attaching itself to an executable program.
 3.they should have a payload.
4. The virus must be able to disguise, by way of encryption or interrupt interception

What is File Infector virus?

“Compiled Virus” types of viruses are compiled into machine-executable instructions, so, that they are executed by the Operating System directly. In addition to infecting files, compiled viruses can reside in the memory of infected systems so that each time a new program is executed, the virus infects the program.

The Compiled virus typically falls into two categories which are as follow;
1 File infector virus
2. Boot sector virus

File Infector Virus-A file infector virus attaches itself to executable programs, such as word processors, spreadsheet applications, and computer games. When the virus has infected a program, it propagates to infect other programs on the system, as well as other systems that use a shared infected program. A virus that attacks the files on a computer is referred to as a file virus or file infector virus. The most frequent file extensions are com, exe, ovl, bin, sys, bat, obj, prg, menu, etc. In all cases, the file viruses act in a similar way. The common file infector viruses are File Virus, Program virus, Parasitic virus, Batch file virus, and Directory Virus. Today we will discuss Directory (cluster) Virus.

What is Directory Virus?

As the name suggests this virus takes direct action when a specific condition is met. A directory virus, also called cluster virus, functions by infecting the directory of your computer. This virus replicates itself and takes action when it is executed. This infects the files and folders in the directory specified in the AUTOEXEC.BAT file path. This file is located in the root directory that is located in the hard disk and this virus will take action at the time of booting.

Whenever the code is executed this virus changes their location into new files but in the hard disk’s root directory. Basically they corrupt the files so this is file infector virus. This type of virus has done damage in the past. Once infected it becomes impossible to locate the original files. Directory virus “Vienna “threatened computers in 1988. Another prominent example of a cluster virus is the Dir-2 virus.

How does Directory Virus work?

The directories(folders) on your computer work exactly like a filing cabinet. You can have a folder within a folder within another folder, the difference on the computer is that you cannot physically see this. Programs you use are also stored with reading the information, in these directories only. Directories (folders) provide a method for organizing files that contain text or images or anything.
A directory virus will modify the paths (directory information) that indicate a location, manipulating them to execute and infect clean files. Now directory entries point to the virus code instead of the actual program. When you run a program with  extension.EXE or.COM, you execute the virus code with an extension such as COM. (command) or EXE. (execute) which executes the virus. then spreading it (directory virus) throughout the system. After the virus has run its course, the original files may be impossible to locate deeming many of your programs useless.

How to remove virus?

All antivirus programs, in general, allow you to perform in-depth scans of your computer. Any malware in your system, no matter how long it’s been there, can be easily identified and eradicated. Premium antivirus options can spot over 95% of known viruses and new infections, so it’s easy to resolve problems quickly.