78 lines
2.0 KiB
Ruby
78 lines
2.0 KiB
Ruby
##
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# $Id$
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##
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##
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# This file is part of the Metasploit Framework and may be subject to
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# redistribution and commercial restrictions. Please see the Metasploit
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# Framework web site for more information on licensing and terms of use.
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# http://metasploit.com/framework/
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##
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require 'msf/core'
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require 'rex/encoder/nonupper'
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class Metasploit3 < 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 as non-alpha based bytes. This allows
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payloads to bypass tolower() calls, but will fail isalpha().
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Table based design from 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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begin
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newchar, state.key, state.decoder_key_size =
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Rex::Encoder::NonUpper::encode_byte(datastore['badchars'], block.unpack('C')[0], state.key, state.decoder_key_size)
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rescue RuntimeError => e
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# This is a bandaid to deal with the fact that, since it's in
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# the Rex namespace, the encoder itself doesn't have access to the
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# Msf exception classes. Turn it into an actual EncodingError
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# exception so the encoder doesn't look broken when it just fails
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# to encode.
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raise BadcharError if e.message == "BadChar"
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end
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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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