How can input validation enhance web application security?

Input validation significantly enhances web application security by ensuring that only expected and safe input is processed. This practice is critical for preventing various types of security vulnerabilities, such as SQL injection, cross-site scripting (XSS), and buffer overflows.

When input validation is implemented, the application checks incoming data against predefined criteria or rules. For example, if a web application expects a user to input a numerical ID, input validation will ensure that only numbers are accepted, rejecting any input that contains letters, special characters, or any other unexpected format. This strict filtering process helps to block malicious data that an attacker might try to inject into the application to exploit vulnerabilities.

Moreover, by validating input on both the client side and the server side, applications can ensure a more robust defense against attacks, thereby protecting sensitive data and maintaining the integrity of the application. This proactive approach is foundational in building secure applications that can withstand common threats and reduces the overall risk of exploitation.