GIAC Foundational Cybersecurity Technologies Practice Test

User input sanitization plays a critical role in web security by specifically protecting against Cross Site Scripting (XSS) vulnerabilities. XSS attacks occur when an attacker is able to inject malicious scripts into a web application through user input fields, which can then be executed in the context of another user's browser. When user input is not properly sanitized, it can allow an attacker to introduce scripts that can manipulate or steal sensitive information, such as session cookies or user credentials.

By implementing effective sanitization measures on user input, developers can ensure that any special characters or potentially harmful code are stripped or encoded before they are processed by the web application. This minimizes the risk of executing unintended commands and safeguards users' data and privacy. In essence, proper sanitization transforms potentially dangerous input into harmless text, thereby thwarting XSS attempts and enhancing overall web security.

While user experience, unauthorized access prevention, and database query performance are important considerations in web development, they do not directly address the specific vulnerabilities posed by XSS as effectively as user input sanitization does.