Many classifications exist for fuzzing based on target, attack vectors used, and fuzzing method. Fuzzing targets include file formats, network protocols, command-line arguments, environment variables, web applications, and many others. Fuzzing can be broadly categorized based on the way test cases are generated. They are mutation fuzzing (dump) and generation fuzzing (intelligent).
A fuzzer that creates completely random input is known as a mutation or dump fuzzer. This type of fuzzer mutates the existing input value blindly. But it lacks an understandable format or structure of the data. For example, it can be replacing or appending a random slice of data to the desired input.