Book a Security Review

Weakness · High

CWE-1385: Missing Origin Validation in WebSockets

What it is

The product uses a WebSocket, but it does not properly verify that the source of data or communication is valid.

MITRE CWE 4.19.1

Severity (our rating)
High
Likelihood of exploit
Not rated by MITRE
Introduced during
Architecture and Design, Implementation
Exploited in the wild
No CVE in CISA's catalog

In more detail

WebSockets provide a bi-directional low latency communication (near real-time) between a client and a server. WebSockets are different than HTTP in that the connections are long-lived, as the channel will remain open until the client or the server is ready to send the message, whereas in HTTP, once the response occurs (which typically happens immediately), the transaction completes. A WebSocket can leverage the existing HTTP protocol over ports 80 and 443, but it is not limited to HTTP. WebSockets can make cross-origin requests that are not restricted by browser-based protection mechanisms such as the Same Origin Policy (SOP) or Cross-Origin Resource Sharing (CORS). Without explicit origin validation, this makes CSRF attacks more powerful.

What an attacker can do

  • Varies by Context (Confidentiality, Integrity, Availability, Non-Repudiation, Access Control)
  • Gain Privileges or Assume Identity (Confidentiality, Integrity, Availability, Non-Repudiation, Access Control)
  • Bypass Protection Mechanism (Confidentiality, Integrity, Availability, Non-Repudiation, Access Control)
  • Read Application Data (Confidentiality, Integrity, Availability, Non-Repudiation, Access Control)
  • Modify Application Data (Confidentiality, Integrity, Availability, Non-Repudiation, Access Control)
  • DoS: Crash, Exit, or Restart (Confidentiality, Integrity, Availability, Non-Repudiation, Access Control)

How to prevent it

Implementation

  • Enable CORS-like access restrictions by verifying the 'Origin' header during the WebSocket handshake.
  • Use a randomized CSRF token to verify requests.
  • Use TLS to securely communicate using 'wss' (WebSocket Secure) instead of 'ws'.
  • Leverage rate limiting to prevent against DoS. Use of the leaky bucket algorithm can help with this.
  • Use a library that provides restriction of the payload size. For example, WS library for Node includes 'maxPayloadoption' that can be set.
  • Treat data/input as untrusted in both directions and apply the same data/input sanitization as XSS, SQLi, etc.

Architecture and Design

  • Require user authentication prior to the WebSocket connection being established. For example, the WS library in Node has a 'verifyClient' function.

CWE-1385 on MITRE's CWE site

H2 Security

Found it in your code?

We review where it appears, fix it with your team, and check it was not already used against you.

Talk to our team

T Academy

Stop writing it in the first place

Learn to build software and systems without weaknesses like this one, with practice on real hosts in your browser, every objective checked on the machine.

Start free

Source: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.