Debuggers are an everyday thing for exploit writers and software crackers, they can read hex and understand exactly what the program is doing. This is how programmers write exploits for your most widely used software like windows and internet explorer, they haven't even gotten to exploit your favorite video multiplayer video game or startup programs installed by devices yet!!

Here's more proof that theres still plenty of exploitable bugs in the most widely used operating system of all. This is a picture of a debugger being run on internet explorer 6 and it found a bug right away. High quality picture available here