I was thinking of attacking the implementation of whatever processes attacker controlled input. If sending 100 pings in a row triggers a stack overflow, this w

I was thinking of attacking the implementation of whatever processes attacker controlled input. If sending 100 pings in a row triggers a stack overflow, this will interest the attacker. I would say that security specific code would be any code that directly processes the untrusted inputs. Parsers and decoders, mostly. You may want to isolate them from the rest of the program (ideally a separate address space), and make sure the interface between them and the rest of the program is much simpler than the input they are processing. At least, you want to ensure such code either produces sound output for the rest of the program or fails cleanly. The attacker will have a harder time exploiting a bug deeper in to the program, I think —hope.