GIAC Foundational Cybersecurity Technologies Practice Test

Which method is effective in mitigating a Cross Site Scripting Attack?

1. Encrypting all user data

2. Sanitizing user input and using third-party libraries

3. Restricting IP addresses accessing the server

4. Implementing a two-factor authentication system

The correct answer is: Sanitizing user input and using third-party libraries

Mitigating a Cross-Site Scripting (XSS) attack effectively relies on the careful handling of user input. Sanitizing user input involves the process of validating and encoding any data that is submitted by users before it is rendered in web pages. This prevents malicious scripts from being executed within the context of a user's browser, which is what makes XSS attacks so dangerous. By using third-party libraries designed specifically for this purpose, developers can leverage established security practices to ensure that provided user data is safe to display. For instance, libraries like DOMPurify can help sanitize HTML input, removing any potential scripts or harmful code that could be executed. This proactive approach minimizes the risk by ensuring that only safe content makes its way into the DOM, effectively blocking XSS attempts. Other methods mentioned, while important for overall web security, do not directly address the unique vulnerabilities posed by XSS. Encrypting user data is vital for data security but does not prevent script execution in a browser. Restricting IP addresses can help protect against unauthorized access but wouldn't necessarily stop an attacker from executing a script from a valid user session. Implementing two-factor authentication improves account security but does not defend against the injection of malicious scripts through input fields. Thus, the best practice