Class: Rex::Encoder::Alpha2::UnicodeUpper

Inherits:
Generic
  • Object
show all
Defined in:
lib/rex/encoder/alpha2/unicode_upper.rb

Class Method Summary collapse

Methods inherited from Generic

add_terminator, encode, encode_byte

Class Method Details

.default_accepted_charsObject


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# File 'lib/rex/encoder/alpha2/unicode_upper.rb', line 10

def self.default_accepted_chars ; ('B' .. 'Z').to_a + ('0' .. '9').to_a ; end

.gen_decoder(reg, offset) ⇒ Object


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# File 'lib/rex/encoder/alpha2/unicode_upper.rb', line 48

def self.gen_decoder(reg, offset)
  decoder =
    gen_decoder_prefix(reg, offset) +
    "QA" +                  # push ecx, NOP
    "TA" +                  # push esp, NOP
    "XA" +                  # pop eax, NOP
    "ZA" +                  # pop edx, NOP
    "PU" +                  # push eax, NOP
    "3" +                   # xor eax, [eax]
    "QA" +                  # push ecx, NOP
    "DA" +                  # inc esp, NOP
    "ZA" +                  # pop edx, NOP
    "BA" +                  # inc edx, NOP
    "RA" +                  # push edx, NOP
    "LA" +                  # dec esp, NOP
    "YA" +                  # pop ecx, NOP
    "IA" +                  # dec ecx, NOP
    "QA" +                  # push ecx, NOP
    "IA" +                  # dec ecx, NOP
    "QA" +                  # push ecx, NOP
    "PA" +                  # push eax, NOP
    "5AAA" +                # xor eax, 41004100 - NOP
    "PA" +                  # push eax, NOP
    "Z" +                   # pop edx
    "1A" +                  # add [ecx], dh - NOP
    "I" +                   # dec ecx
    "1A" +                  # add [ecx], dh - NOP
    "IA" +                  # dec ecx, NOP
    "IA" +                  # dec ecx, NOP
    "J" +                   # dec edx
    "1" +                   # add [ecx], dh
    "1A" +                  # add [ecx], dh - NOP
    "IA" +                  # dec ecx, NOP
    "IA" +                  # dec ecx, NOP
    "XA" +                  # pop eax, NOP
    "58AA" +                # xor eax, 41003800 - NOP
    "PA" +                  # push eax, NOP
    "ZA" +                  # pop edx, NOP
    "BA" +                  # inc edx, NOP
    "B" +                   # inc edx
    "Q" +                   # add [ecx], dl
    "I" +                   # dec ecx
    "1A" +                  # add [ecx], dh - NOP
    "I" +                   # dec ecx
    "Q" +                   # add [ecx], dl
    "IA" +                  # dec ecx, NOP
    "I" +                   # dec ecx
    "Q" +                   # add [ecx], dl
    "I" +                   # dec ecx
    "1" +                   # add [ecx], dh
    "1" +                   # add [ecx], dh
    "1" +                   # add [ecx], dh
    "1A" +                  # add [ecx], dh - NOP
    "IA" +                  # dec ecx, NOP
    "J" +                   # dec edx
    "Q" +                   # add [ecx], dl
    "I" +                   # dec edx
    "1A" +                  # add [ecx], dh - NOP
    "YA" +                  # pop ecx, NOP
    "ZB" +                  # pop edx, NOP
    "AB" +                  # inc ecx, NOP      <-------
    "AB" +                  # inc ecx, NOP              |
    "AB" +                  # inc ecx, NOP              |
    "AB" +                  # inc ecx, NOP              |
    "30" +                  # imul eax, [ecx], 10 *     |
    "A" +                   # add al, [ecx+2] *         |
    "P" +                   # mov [edx], al *           |
    "B" +                   # inc edx                   |
    "9" +                   # cmp [ecx], 41 *           |
    "4" +                   # jnz   --------------------
    "4JB"

  return decoder
end

.gen_decoder_prefix(reg, offset) ⇒ Object


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# File 'lib/rex/encoder/alpha2/unicode_upper.rb', line 17

def self.gen_decoder_prefix(reg, offset)
  if (offset > 6)
    raise "Critical: Offset is greater than 6"
  end

  # offset untested for unicode :(
  if (offset <= 4)
    nop = 'CP' * offset
    mod = 'IA' * (4 - offset) + nop    # dec ecx,,, push ecx, pop edx
  else
    mod = 'AA' * (offset - 4)          # inc ecx
    nop = 'CP' * (4 - mod.length)
    mod += nop
  end

  regprefix = {                      # nops ignored below
    'EAX'   => 'PPYA' + mod,        # push eax, pop ecx
    'ECX'   =>  mod + '4444',       # dec ecx
    'EDX'   => 'RRYA' + mod,        # push edx, pop ecx
    'EBX'   => 'SSYA' + mod,        # push ebx, pop ecx
    'ESP'   => 'TUYA' + mod,        # push esp, pop ecx
    'EBP'   => 'UUYA' + mod,        # push ebp, pop ecx
    'ESI'   => 'VVYA' + mod,        # push esi, pop ecx
    'EDI'   => 'WWYA' + mod,        # push edi, pop edi
    '[ESP]' => 'YA' + mod + '44',   #
    '[ESP+4]' => 'YUYA' + mod,      #
  }

  return regprefix[reg]
end

.gen_second(block, base) ⇒ Object


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# File 'lib/rex/encoder/alpha2/unicode_upper.rb', line 12

def self.gen_second(block, base)
  # unicode uses additive encoding
  (block - base)
end