62 lines
1.5 KiB
Ruby
62 lines
1.5 KiB
Ruby
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require 'msf/core'
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require 'rex/encoder/nonupper'
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module Msf
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module Encoders
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module X86
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class NonUpper < Msf::Encoder::NonUpper
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Rank = LowRanking
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def initialize
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super(
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'Name' => "Non-Upper Encoder",
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'Version' => '$Revision$',
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'Description' => %q{
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Encodes payloads a non-alpha based bytes. This allows
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payloads to bypass both tolower() calls,
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but will fail isalpha(). Table based design from
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Russel Sanford.
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},
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'Author' => [ 'pusscat'],
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'Arch' => ARCH_X86,
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'License' => BSD_LICENSE,
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'EncoderType' => Msf::Encoder::Type::NonUpper,
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'Decoder' =>
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{
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'BlockSize' => 1,
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})
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end
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#
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# Returns the decoder stub that is adjusted for the size of the buffer
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# being encoded.
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#
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def decoder_stub(state)
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state.key = ""
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state.decoder_key_size = 0
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Rex::Encoder::NonUpper::gen_decoder()
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end
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#
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# Encodes a one byte block with the current index of the length of the
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# payload.
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#
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def encode_block(state, block)
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newchar, state.key, state.decoder_key_size = Rex::Encoder::NonUpper::encode_byte(datastore['badchars'], block.unpack('C')[0], state.key, state.decoder_key_size)
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return newchar
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end
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#
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# Fix stuff, and add the table :)
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#
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def encode_end(state)
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state.encoded.gsub!(/A/, state.decoder_key_size.chr)
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state.encoded.gsub!(/B/, (state.decoder_key_size+5).chr)
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state.encoded[0x24, 0] = state.key
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end
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end
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end end end
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