Compare OWASP WSFuzzer vs. Sulley

Fuzz testing, commonly referred to as fuzzing, is a technique used in software testing that aims to discover implementation errors by injecting malformed or semi-malformed data in an automated way. For example, consider a scenario involving an integer variable within a program that captures a user's selection among three questions; the user's choice can be represented by the integers 0, 1, or 2, resulting in three distinct cases. Since integers are typically stored as fixed-size variables, a failure to implement the default switch case securely could lead to program crashes and various traditional security vulnerabilities. Fuzzing serves as an automated method for uncovering software implementation issues, enabling the identification of bugs when they occur. A fuzzer is a specialized tool designed to automatically inject semi-random data into the program stack, aiding in the detection of anomalies. The process of generating this data involves the use of generators, while the identification of vulnerabilities often depends on debugging tools that can analyze the program's behavior under the influence of the injected data. These generators typically utilize a mixture of established static fuzzing vectors to enhance the testing process, ultimately contributing to more robust software development practices.

Sulley is a comprehensive fuzz testing framework and engine that incorporates various extensible components. In my view, it surpasses the functionality of most previously established fuzzing technologies, regardless of whether they are commercial or available in the public domain. The framework is designed to streamline not only the representation of data but also its transmission and instrumentation processes. As a fully automated fuzzing solution developed entirely in Python, Sulley operates without requiring human intervention. Beyond impressive capabilities in data generation, Sulley offers a range of essential features expected from a contemporary fuzzer. It meticulously monitors network activity and keeps detailed records for thorough analysis. Additionally, Sulley is equipped to instrument and evaluate the health of the target system, with the ability to revert to a stable state using various methods when necessary. It efficiently detects, tracks, and categorizes faults that arise during testing. Furthermore, Sulley has the capability to perform fuzzing in parallel, which dramatically enhances testing speed. It can also autonomously identify unique sequences of test cases that lead to faults, thereby improving the overall effectiveness of the testing process. This combination of features positions Sulley as a powerful tool for security testing and vulnerability detection.