You’ve got a bunch of gold sitting around because it’s holding its value great against inflation or because you are a dragon or something.
The first thing you will want to do is protect your valuable gold. The most obvious thing is to start off with a wall.
You do your research and build a wall or get someone to build one for you to the best standards of the time.
You now rest assured in the knowledge that your valuable plunder investment is safe.
People come from all over to marvel at your great wall.
It turns out that right under your nose, one of the people coming to look at the wall every day has been looking at it very closely and found a set of bricks they can use to climb up and over it.
Nothing has fundamentally changed in your wall’s construction, yet suddenly, with the knowledge of where to climb up, your gold is effectively unguarded. Even worse, this person might sneak in and out many times, slowly taking gold bit by bit for days, weeks, or years without you noticing, or sharing this information with someone else that does the same.
In this case, the gold is your users’ data or elevated privileges to your system. The wall is any dependencies you are using or have written yourself.
In the end, our biggest enemy in cybersecurity isn’t just the hackers or the vulnerabilities – it’s time itself. Just as Andy Dufresne in Shawshank Redemption slowly chipped away at his cell wall over decades, patient attackers have all the time in the world to probe and exploit our code, as long as it remains public and unchanged.