Adhoc scan of hostname calls a non-existent accessor in method

[BrianWGray]

scan.rb includes a method _append_asset! which calls an accessor that does not appear to be set at any point.

On line 238 host.text is assigned asset.host but asset is passed as a string value to the method.
host.text = asset.host

By changing asset.host to asset so it's string value is used allows the methods that call _append_asset! to function properly. Specifically, scan_asset -> scan_assets.

Ruby code that reproduces the issue:

#!/usr/bin/env ruby
require 'optparse'
require 'rubygems'
require 'highline/import'
require 'nexpose'
include Nexpose
 
@host = '<hostname>'
@port = 3780
@user = 'nxadmin'
 
OptionParser.new do |opts|
  opts.banner = "Usage: ruby #{File::basename($0)} [options] <asset> <site-id>"
  opts.separator ''
  opts.separator 'This script will add an asset to a specified site and then launch a scan on that asset with the sites configurations'
  opts.separator ''
  opts.separator %Q{A site must already exist for this script to run against.}
  opts.separator ''
  opts.separator 'Note that this script will always prompt for a connection password.'
  opts.separator ''
  opts.separator 'Options:'
  opts.on('-h', "--host HOST", "IP or hostname of Nexpose console. Defaults to #{@host} if not provided.") { |host| @host = host }
  opts.on('-p', "--port PORT", Integer, "Port of Nexpose console. Defaults to #{@port} if not provided.") { |port| @port = port }
  opts.on('-u', "--user USER", "Username to connect to Nexpose with. Defaults to #{@user} if not provided.") { |user| @user = user }
  opts.on_tail('--help', "Print this help message.") { puts opts; exit }
end.parse!
 
unless ARGV[0]
  $stderr.puts 'Asset is required.'
  exit(1)
end
asset = ARGV[0]
 
unless ARGV[1]
  $stderr.puts 'Site ID is required.'
  exit(1)
end
site_id = ARGV[1]
 
def get_password(prompt = 'Password: ')
  ask(prompt) { |query| query.echo = false }
end
@password = get_password
 
nsc = Nexpose::Connection.new(@host, @user, @password, @port)

begin
    nsc.login
    rescue ::Nexpose::APIError => err
    $stderr.puts("Connection to #{@host} failed: #{err.reason}")
    exit(1)
    raise
end

at_exit { nsc.logout }

site = Site.load(nsc, site_id)
puts "Adding the asset #{asset} to the site #{site_id}"
site.include_asset(asset)
site.save(nsc)

=begin
## Patch
class Nexpose::Connection

    # Utility method for appending a HostName or IPRange object into an
    # XML object, in preparation for ad hoc scanning.
    #
    # @param [REXML::Document] xml Prepared API call to execute.
    # @param [HostName|IPRange] asset Asset to append to XML.
    #
    def _append_asset!(xml, asset)
      if asset.is_a? IPRange
        xml.add_element('range', 'from' => asset.from, 'to' => asset.to)
      else  # Assume HostName
        host = REXML::Element.new('host')
        host.text = asset
        xml.add_element(host)
      end
    end
end
=end

puts "Now Scanning asset #{asset}."
scan = nsc.scan_asset(site_id, asset)
 
begin 
  sleep(30) 
  status = nsc.scan_status(scan.id) 
  puts "Current scan status: #{status.to_s}" 
end while status == Nexpose::Scan::Status::RUNNING 

Context

Submitting the issue on behalf of https://community.rapid7.com/thread/9166

Error posted to community:
C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/nexpose-5.3.1/lib/nexpose/scan.rb:238:in _append_asset!': undefined method host
' for "beans.domains.com":String (NoMethodError)
from C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/nexpose-5.3.1/lib/nexpose/scan.rb:112:in block in scan_assets' from C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/nexpose-5.3.1/lib/nexpose/scan.rb:112:in each'
from C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/nexpose-5.3.1/lib/nexpose/scan.rb:112:in scan_assets' from C:/Ruby23-x64/lib/ruby/gems/2.3.0/gems/nexpose-5.3.1/lib/nexpose/scan.rb:83:in scan_asset'
from ./add_asset_to_site_and_scan.rb:57:in `

'