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##
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# This module requires Metasploit: https://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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class MetasploitModule < Msf::Encoder
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  Rank = GreatRanking
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  def initialize
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    super(
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      'Name' => 'Ruby Base64 Encoder',
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      'Description' => %q{
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        This encoder returns a base64 string encapsulated in
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        eval(%(base64 encoded string).unpack(%(m0)).first).
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      },
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      'Author' => 'Robin Stenvi <robin.stenvi[at]gmail.com>',
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      'License' => BSD_LICENSE,
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      'Arch' => ARCH_RUBY)
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  end
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  def encode_block(state, buf)
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    %w[( ) . % e v a l u n p c k m 0 f i r s t].each do |c|
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      raise BadcharError if state.badchars.include?(c)
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    end
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    b64 = Rex::Text.encode_base64(buf)
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    state.badchars.each_byte do |byte|
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      raise BadcharError if b64.include?(byte.chr)
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    end
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    return 'eval(%(' + b64 + ').unpack(%(m0)).first)'
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  end
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end
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