It is not the fact that fuzz or mud testing breaks everything, but yes, it is proven that testers can find some serious bugs using monkey testing. Scenarios such as navigation, pagination, clicking on buttons multiple times, searching with random data, setting up a web page, inputting alphanumeric data in the number text field, tab keys, space bar, enter key and other permutation and combination are the cases that tester have to deal with.
Sometimes, the tester doesn’t test such basic scenarios but eventually, it breaks the application. In real-time users may not test these types of scenarios. Fuzz testing can cover serious crashes and is very helpful in testing the accuracy of the software. QA service companies work on every type of testing and fuzz testing is done in both functional and automation.
Identify Target System → Identify Inputs → Generate Fuzzed Data → Execute Fuzzed Data → Monitor System Behavior → Log Defects
To recapitulate, undoubtedly fuzz testing is valid and shows the presence of bugs in the application. On the other hand, it cannot guarantee the complete detection of bugs in an application.