I would like to record the output corresponding to each input during fuzzing, and when it is not equal to a specific value (instead of crashing) is to raise the fitness of the corresponding input. However, I have searched for the current mainstream tools like AFL, AFL++, etc. and found that they seem to focus more on program crashes. If I want to implement such a feature, but not develop a new fuzzer from scratch, what should I do?
I've noticed that most fuzzers only log cases when the program crashes or the corresponding sanitizer is triggered, but what I want is to log cases when a particular input is different from a particular value.