Definition
Fuzzing, or fuzz testing, is an automated software testing technique that involves providing invalid, unexpected, or random data as inputs to a computer program. The goal is to discover software defects, security vulnerabilities, or unexpected behavior by observing how the program handles these malformed inputs. This process works by systematically feeding a program a large volume of malformed data, often generated by specialized tools, and monitoring for crashes, memory leaks, or assertion failures. Fuzzing is crucial for improving software robustness and security by identifying flaws that might otherwise go unnoticed during traditional testing. For instance, fuzzing a web browser's parsing engine could uncover a vulnerability allowing an attacker to execute arbitrary code. It differs from traditional unit testing in its focus on unexpected inputs rather than predefined test cases. This technique is frequently covered in cybersecurity certifications like CompTIA Security+ and CySA+.