CVE-2022-36045: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) (CWE-338)
value: NodeBB Forum Software is powered by Node.js and supports either Redis, MongoDB, or a PostgreSQL database. It utilizes web sockets for instant interactions and real-time notifications. `utils.generateUUID`, a helper function available in essentially all versions of NodeBB (as far back as v1.0.1 and potentially earlier) used a cryptographically insecure Pseudo-random number generator (`Math.random()`), which meant that a specially crafted script combined with multiple invocations of the password reset functionality could enable an attacker to correctly calculate the reset code for an account they do not have access to. This vulnerability impacts all installations of NodeBB. The vulnerability allows for an attacker to take over any account without the involvement of the victim, and as such, the remediation should be applied immediately (either via NodeBB upgrade or cherry-pick of the specific changeset. The vulnerability has been patched in version 2.x and 1.19.x. There is no known workaround, but the patch sets listed above will fully patch the vulnerability.
CWE description: The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.
CVSS v3 base score: 9.8
Published: 2022-08-31T15:15Z
Repository: https://github.com/NodeBB/NodeBB
Language: JavaScript
Files changed: public/src/utils.common.js, public/src/utils.js, src/utils.js
Commit date: 2022-05-26 12:12:19 -0400
Commit message: fix: get rid of math.random in utils.generateUUID

Diff: diff --git a/public/src/utils.common.js b/public/src/utils.common.js
index 3860861ee0..da1c24c010 100644
--- a/public/src/utils.common.js
+++ b/public/src/utils.common.js
@@ -272,19 +272,10 @@ const HTMLEntities = Object.freeze({
 	'diams;': 9830,
 });
 
 /* eslint-disable no-redeclare */
 const utils = {
-	generateUUID: function () {
-		/* eslint-disable no-bitwise */
-		return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function (c) {
-			const r = Math.random() * 16 | 0;
-			const v = c === 'x' ? r : ((r & 0x3) | 0x8);
-			return v.toString(16);
-		});
-		/* eslint-enable no-bitwise */
-	},
 	// https://github.com/substack/node-ent/blob/master/index.js
 	decodeHTMLEntities: function (html) {
 		return String(html)
 			.replace(/&#(\d+);?/g, function (_, code) {
 				return String.fromCharCode(code);
diff --git a/public/src/utils.js b/public/src/utils.js
index f57d68c354..50ed3960c2 100644
--- a/public/src/utils.js
+++ b/public/src/utils.js
@@ -71,6 +71,14 @@ utils.assertPasswordValidity = (password) => {
 	if (passwordStrength.score < ajaxify.data.minimumPasswordStrength) {
 		throw new Error('[[user:weak_password]]');
 	}
 };
 
+utils.generateUUID = function () {
+	// from https://github.com/tracker1/node-uuid4/blob/master/browser.js
+	const temp_url = URL.createObjectURL(new Blob());
+	const uuid = temp_url.toString();
+	URL.revokeObjectURL(temp_url);
+	return uuid.split(/[:\/]/g).pop().toLowerCase(); // remove prefixes
+};
+
 module.exports = utils;
diff --git a/src/utils.js b/src/utils.js
index 524730f221..3607f9b2d3 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -1,7 +1,9 @@
 'use strict';
 
+const crypto = require('crypto');
+
 process.profile = function (operation, start) {
 	console.log('%s took %d milliseconds', operation, process.elapsedTimeSince(start));
 };
 
 process.elapsedTimeSince = function (start) {
@@ -12,6 +14,19 @@ const utils = require('../public/src/utils.common');
 
 utils.getLanguage = function () {
 	const meta = require('./meta');
 	return meta.config && meta.config.defaultLang ? meta.config.defaultLang : 'en-GB';
 };
+
+utils.generateUUID = function () {
+	// from https://github.com/tracker1/node-uuid4/blob/master/index.js
+	let rnd = crypto.randomBytes(16);
+	/* eslint-disable no-bitwise */
+	rnd[6] = (rnd[6] & 0x0f) | 0x40;
+	rnd[8] = (rnd[8] & 0x3f) | 0x80;
+	/* eslint-enable no-bitwise */
+	rnd = rnd.toString('hex').match(/(.{8})(.{4})(.{4})(.{4})(.{12})/);
+	rnd.shift();
+	return rnd.join('-');
+};
+
 module.exports = utils;

Vulnerable code: 	generateUUID: function () {
		/* eslint-disable no-bitwise */
		return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function (c) {
			const r = Math.random() * 16 | 0;
			const v = c === 'x' ? r : ((r & 0x3) | 0x8);
			return v.toString(16);
		});
		/* eslint-enable no-bitwise */
	},
Fixed code: utils.generateUUID = function () {
	// from https://github.com/tracker1/node-uuid4/blob/master/browser.js
	const temp_url = URL.createObjectURL(new Blob());
	const uuid = temp_url.toString();
	URL.revokeObjectURL(temp_url);
	return uuid.split(/[:\/]/g).pop().toLowerCase(); // remove prefixes
};

const crypto = require('crypto');


utils.generateUUID = function () {
	// from https://github.com/tracker1/node-uuid4/blob/master/index.js
	let rnd = crypto.randomBytes(16);
	/* eslint-disable no-bitwise */
	rnd[6] = (rnd[6] & 0x0f) | 0x40;
	rnd[8] = (rnd[8] & 0x3f) | 0x80;
	/* eslint-enable no-bitwise */
	rnd = rnd.toString('hex').match(/(.{8})(.{4})(.{4})(.{4})(.{12})/);
	rnd.shift();
	return rnd.join('-');
};