Mutation Fuzzing

There are typically two methods for producing fuzz data that is sent to a target, Generation or Mutation. Generational fuzzers are capable of building the data being sent based on a data model provided by the fuzzer creator. Sometimes this is simple and dumb as sending random bytes, or much smarter by knowing good values and combining them in interesting ways.

Mutation on the other hand starts out with a known good "template" which is then modified. However, nothing that is not present in the "template" or "seed" will be produced. For example, if a file format specified 18 types of chunks or optional data segments and the "template"/"seed" only used four (4) of them, a mutational based fuzzer would never generate the other chunks not present only modify the chunks it is presented with.