Open Source Fuzzing Tools

If your company develops software or services, one of the first questions you should ask is, "why should I run fuzzers?" The answer to that, touched on in earlier chapters, should be straightforward.
Put simply, fuzzers are effective at finding bugs.
Fuzzers save time and are cheap alternatives to manual security testing.
External security researchers and malicious individuals will run them for you if you do not.
In other words, fuzzers reduce test costs, find bugs, and help in preventing folks outside your organization from finding embarrassing flaws in your software. Sign me up! So, if your product is actively taking user input from outside sources, the question really isn't "should I run a fuzzer," but "how do I get started?"
Before we jump into how to integrate and implement fuzzing into your development cycle, we'll dig deeper into why fuzzers are important to run.
For anyone who has ever worked in Quality Assurance, it should be obvious that you are always resource and time constrained. That given with the old test adage, "you can only prove the existence of bugs, but not the absence of them," are two particular reasons why performing security testing can be difficult. The test team has a long grocery list of types of tests to run, including, but not limited to:
Unit testing
Integration testing
Scenario testing
Functionality testing
Reliability testing
Performance testing
Accessibility testing
Testability analysis
Usability testing
Internationalization...