Class: Rex::Encoder::Alpha2::UnicodeMixed

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

Class Method Summary collapse

Methods inherited from Generic

add_terminator, default_accepted_chars, encode, encode_byte

Class Method Details

.gen_decoder(reg, offset) ⇒ Object 



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# File 'lib/rex/encoder/alpha2/unicode_mixed.rb', line 45

def self.gen_decoder(reg, offset)
	decoder =
		gen_decoder_prefix(reg, offset) +
		"j" +               # push 0
		"XA" +              # pop eax, NOP
		"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
		"IA" +              # dec ecx, NOP
		"hAAA" +            # push 00410041, NOP
		"Z" +               # pop edx
		"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
		"BA" +              # inc 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], dh
		"I" +               # dec ecx
		"1" +               # add [ecx], dh
		"1" +               # add [ecx], dh
		"1A" +              # add [ecx], dh NOP
		"IA" +              # dec ecx, NOP
		"J" +               # dec edx
		"Q" +               # add [ecx], dl 
		"YA" +              # pop ecx, NOP
		"Z" +               # pop edx
		"B" +               # add [edx], al
		"A" +               # inc ecx       <-------
		"B" +               # add [edx], al         |
		"A" +               # inc ecx               |
		"B" +               # add [edx], al         |
		"A" +               # inc ecx               |
		"B" +               # add [edx], al         |
		"A" +               # inc ecx               |
		"B" +               # add [edx], al         |
		"kM" +              # imul eax, [eax], 10 * |
		"A" +               # add [edx], al         |
		"G" +               # inc edi               | 
		"B" +               # add [edx], al         |
		"9" +               # cmp [eax], eax        |
		"u" +               # jnz ------------------      
		"4JB"

	return decoder
end

.gen_decoder_prefix(reg, offset) ⇒ Object 



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

def self.gen_decoder_prefix(reg, offset)
	if (offset > 21)
		 raise "Critical: Offset is greater than 21"
	end

	# offset untested for unicode :(
	if (offset <= 14)
		nop = 'CP' * offset
		mod = 'IA' * (14 - offset) + nop    # dec ecx,,, push ecx, pop edx
	else
		mod = 'AA' * (offset - 14)			# inc ecx
		nop = 'CP' * (14 - 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
	}

	return regprefix[reg]	
end

.gen_second(block, base) ⇒ Object 



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

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