Missing Origin Validation in WebSockets

Opis

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

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.

Inne nazwy

Cross-Site WebSocket hijacking (CSWSH)

this term is used for attacks that exploit this weakness

Skutki

• Confidentiality, Integrity, Availability, Non-Repudiation, Access Control

  Varies by Context; Gain Privileges or Assume Identity; Bypass Protection Mechanism; Read Application Data; Modify Application Data; DoS: Crash, Exit, or Restart

  The consequences will vary depending on the nature of the functionality that is vulnerable to CSRF. An attacker could effectively perform any operations as the victim. If the victim is an administrator or privileged user, the consequences may include obtaining complete control over the web application - deleting or stealing data, uninstalling the product, or using it to launch other attacks against all of the product's users. Because the attacker has the identity of the victim, the scope of the CSRF is limited only by the victim's privileges.

Zapobieganie

• Implementation

  Enable CORS-like access restrictions by verifying the 'Origin' header during the WebSocket handshake.

• Implementation

  Use a randomized CSRF token to verify requests.

• Implementation

  Use TLS to securely communicate using 'wss' (WebSocket Secure) instead of 'ws'.

• Architecture and Design, Implementation

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

• Implementation

  Leverage rate limiting to prevent against DoS. Use of the leaky bucket algorithm can help with this.

  Skuteczność: Defense in Depth

• Implementation

  Use a library that provides restriction of the payload size. For example, WS library for Node includes 'maxPayloadoption' that can be set.

  Skuteczność: Defense in Depth

• Implementation

  Treat data/input as untrusted in both directions and apply the same data/input sanitization as XSS, SQLi, etc.

Przykłady podatności

• CVE-2020-25095 web console for SIEM product does not check Origin header, allowing Cross Site WebSocket Hijacking (CSWH)
• CVE-2018-6651 Chain: gaming client attempts to validate the Origin header, but only uses a substring, allowing Cross-Site WebSocket hijacking by forcing requests from an origin whose hostname is a substring of the valid origin.
• CVE-2018-14730 WebSocket server does not check the origin of requests, allowing attackers to steal developer's code using a ws://127.0.0.1:3123/ connection.
• CVE-2018-14731 WebSocket server does not check the origin of requests, allowing attackers to steal developer's code using a ws://127.0.0.1/ connection to a randomized port number.
• CVE-2018-14732 WebSocket server does not check the origin of requests, allowing attackers to steal developer's code using a ws://127.0.0.1:8080/ connection.

Słabość nadrzędna

• CWE-346 Origin Validation Error

Kiedy powstaje

• Architecture and Design
• Implementation

Dotyczy

Not Language-Specific, Web Based, Web Server

Źródła

1. Cross-Site WebSocket Hijacking (CSWSH) — Christian Schneider, 2013
2. WebSockets not Bound by SOP and CORS? Does this mean... — Drew Branch, 2018
3. How to secure your WebSocket connections — Mehul Mohan, 2018
4. Cross-Site WebSocket Hijacking (CSWSH) — Vickie Li, 2019
5. Testing for WebSockets security vulnerabilities — PortSwigger, Using cross-site WebSockets to exploit vulnerabilities