Client Side Vulnerabilities / Websocket URL Poisoning (DOM-Based)

Description

WebSocket URL poisoning (DOM-based) is a type of client-side vulnerability that can be exploited to inject malicious data into a websocket URL. This vulnerability is listed in the Common Weakness Enumeration (CWE) directory under CWE-918, and is described in the OWASP Testing Guide as a potential vector for Cross-Site Scripting (XSS) attacks. It occurs when an attacker injects malicious data into the websocket URL and can allow the execution of arbitrary code within the web browser.

Risk

The risk associated with this vulnerability is that it can lead to a wide variety of malicious activity, including information leakage, denial of service, and unauthorized access to sensitive data. The risk of exploitation is high due to the fact that the vulnerability exists in the client-side code, making it difficult for organizations to detect and mitigate against.

Solution

The best solution to this vulnerability is to ensure that all websocket URLs are properly validated and sanitized before being used to handle requests from the client-side. Additionally, web application firewalls can be used to detect and block malicious requests.

Example

The following example shows a vulnerable code snippet that can be exploited to perform websocket URL poisoning:

var url = "ws://example.com/ws?data=" + document.location;
var ws = new WebSocket(url);

In this example, the document.location object is used in the websocket URL, which can be manipulated by an attacker to inject malicious data.