First layer – network layer

This is the first layer of the Defense in Depth approach to the cloud environment.

Since the network layer is the first entry point for users in the cloud environment, both the genuine client as well as malicious attacker will come through this. This is one of the reasons why designing this layer is one of the most important things that needs to be done in an organization.

The technologies and techniques that are a part of the network layer are generally firewalls, IPS/IDS systems, DMZ, network segmentation, data loss prevention systems, public key infrastructure, and many more.

If a malicious user is able to bypass the network layer security mechanisms due to either some kind of attack or misconfiguration from the organization's side, the next layer for security is generally the platform layer.

For example, Small Corp. has ten servers behind a firewall. Due to some misconfiguration in the firewall, the rule associated with port 22 is 0.0.0.0/0, thus it is open to the world. This gives an attacker a good chance to bypass one layer of defense and try and directly exploit and connect to the server.