No.4 - Manage your attack surface

Most opportunistic attacks will start with a scan of your perimeter. This is everything someone without special access can see. There's a lot you can do to minimise this and make sure it looks boring to an attacker. If it seems high risk and low reward, an opportunistic attacker will go elsewhere, and a targeted attacker will find it harder to get in.

In addition to network firewalls that sit between your network and the internet, you should run application firewalls that sit between your application and the internet. It’s important to ensure your systems are built to a consistent standard and hardened using a reference such as the?CIS Security Benchmarks. Don't forget to turn off ports and services you don’t need and only have systems face externally if they need to.