Well in that case, I have only a surface level understanding of Valgrind, but I use it for those rare times I code in C. I also don't know how afl works at the

Well in that case, I have only a surface level understanding of Valgrind, but I use it for those rare times I code in C. I also don't know how afl works at the code modification level, other than that it asks gcc to add some instrumentation, but I've used it to find bugs. :) I completely agree with your last statement, with one proviso. You will always have an incomplete picture of the application's security posture. The fundamentals include hardware and OS behaviors, power consumption, RF emissions, and other fields which are very far from purity of the programming language model. Acquisition of all of this knowledge is very difficult, but is also rarely needed. I think for most cases it's okay to have an incomplete understanding of the tools. It depends on the threat model.