You cannot learn to make a secure lock if you don't know how to pick a lock.

Similarly, you can't build a secure system if you don't know how you'd crack a secure system.

Of course, you don't have to really know exactly which tools to use but you'd still have to know the common methods of attack, how they work, what type of tools people might use.

Once you know that, you can take steps to defeat the tools and workarounds.