DOM-based Cross-Site Scripting

The DOM-based Cross-Site Scripting (DOM XSS) vulnerability allows attackers to execute malicious scripts in the client's browser. By injecting code into the Document Object Model (DOM), attackers can manipulate the application's behavior and compromise user data.

The risk is that the code injected by an attacker could potentially lead to effects such as stealing session cookies, calling application features on behalf of another user, or exploiting browser vulnerabilities.

To mitigate DOM-based XSS attacks, it's essential to handle user input with caution and ensure proper encoding and escaping on the client side. Implementing a Content Security Policy (CSP) and using the HTTPOnly cookie flag can enhance protection. Avoid inserting untrusted content directly into HTML using methods like innerHTML or document.write(), as these are vulnerable to malicious scripts. Instead, use safer alternatives like document.createElement() and Element.textContent. If unsafe methods must be used, sanitize inputs with an HTML sanitization library such as DOMPurify. Additionally, regularly update and audit JavaScript libraries and frameworks to address potential vulnerabilities.