124 lines
4.3 KiB
Ruby
124 lines
4.3 KiB
Ruby
#!/usr/bin/env ruby
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require 'rex/encoder/alpha2/generic'
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module Rex
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module Encoder
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module Alpha2
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class UnicodeUpper < Generic
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def self.default_accepted_chars ; ('B' .. 'Z').to_a + ('0' .. '9').to_a ; end
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def self.gen_second(block, base)
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# unicode uses additive encoding
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(block - base)
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end
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def self.gen_decoder_prefix(reg, offset)
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if (offset > 6)
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raise "Critical: Offset is greater than 6"
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end
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# offset untested for unicode :(
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if (offset <= 4)
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nop = 'CP' * offset
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mod = 'IA' * (4 - offset) + nop # dec ecx,,, push ecx, pop edx
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else
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mod = 'AA' * (offset - 4) # inc ecx
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nop = 'CP' * (4 - mod.length)
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mod += nop
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end
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regprefix = { # nops ignored below
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'EAX' => 'PPYA' + mod, # push eax, pop ecx
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'ECX' => mod + '4444', # dec ecx
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'EDX' => 'RRYA' + mod, # push edx, pop ecx
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'EBX' => 'SSYA' + mod, # push ebx, pop ecx
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'ESP' => 'TUYA' + mod, # push esp, pop ecx
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'EBP' => 'UUYA' + mod, # push ebp, pop ecx
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'ESI' => 'VVYA' + mod, # push esi, pop ecx
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'EDI' => 'WWYA' + mod, # push edi, pop edi
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'[ESP]' => 'YA' + mod + '44', #
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'[ESP+4]' => 'YUYA' + mod, #
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}
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return regprefix[reg]
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end
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def self.gen_decoder(reg, offset)
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decoder =
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gen_decoder_prefix(reg, offset) +
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"QA" + # push ecx, NOP
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"TA" + # push esp, NOP
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"XA" + # pop eax, NOP
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"ZA" + # pop edx, NOP
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"PU" + # push eax, NOP
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"3" + # xor eax, [eax]
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"QA" + # push ecx, NOP
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"DA" + # inc esp, NOP
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"ZA" + # pop edx, NOP
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"BA" + # inc edx, NOP
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"RA" + # push edx, NOP
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"LA" + # dec esp, NOP
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"YA" + # pop ecx, NOP
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"IA" + # dec ecx, NOP
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"QA" + # push ecx, NOP
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"IA" + # dec ecx, NOP
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"QA" + # push ecx, NOP
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"PA" + # push eax, NOP
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"5AAA" + # xor eax, 41004100 - NOP
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"PA" + # push eax, NOP
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"Z" + # pop edx
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"1A" + # add [ecx], dh - NOP
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"I" + # dec ecx
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"1A" + # add [ecx], dh - NOP
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"IA" + # dec ecx, NOP
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"IA" + # dec ecx, NOP
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"J" + # dec edx
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"1" + # add [ecx], dh
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"1A" + # add [ecx], dh - NOP
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"IA" + # dec ecx, NOP
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"IA" + # dec ecx, NOP
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"XA" + # pop eax, NOP
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"58AA" + # xor eax, 41003800 - NOP
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"PA" + # push eax, NOP
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"ZA" + # pop edx, NOP
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"BA" + # inc edx, NOP
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"B" + # inc edx
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"Q" + # add [ecx], dl
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"I" + # dec ecx
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"1A" + # add [ecx], dh - NOP
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"I" + # dec ecx
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"Q" + # add [ecx], dl
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"IA" + # dec ecx, NOP
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"I" + # dec ecx
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"Q" + # add [ecx], dl
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"I" + # dec ecx
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"1" + # add [ecx], dh
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"1" + # add [ecx], dh
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"1" + # add [ecx], dh
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"1A" + # add [ecx], dh - NOP
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"IA" + # dec ecx, NOP
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"J" + # dec edx
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"Q" + # add [ecx], dl
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"I" + # dec edx
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"1A" + # add [ecx], dh - NOP
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"YA" + # pop ecx, NOP
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"ZB" + # pop edx, NOP
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"AB" + # inc ecx, NOP <-------
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"AB" + # inc ecx, NOP |
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"AB" + # inc ecx, NOP |
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"AB" + # inc ecx, NOP |
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"30" + # imul eax, [ecx], 10 * |
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"A" + # add al, [ecx+2] * |
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"P" + # mov [edx], al * |
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"B" + # inc edx |
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"9" + # cmp [ecx], 41 * |
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"4" + # jnz --------------------
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"4JB"
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return decoder
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end
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end end end end
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