MD3 Defence in depth

Question 1

Defence in depth

Answer 1

A layered defense is difficult to penetrate. When one barrier fails, another takes its place to stop an attack. Defense in depth is a security model that makes use of this concept. It’s a layered approach to vulnerability management that reduces risk. Defense in depth is commonly referred to as the castle approach because it resembles the layered defenses of a castle.

Question 2

Defence in depth II

Answer 2

The defense in depth concept can be used to protect any asset. It’s mainly used in cybersecurity to protect information using a five layer design. Each layer features a number of security controls that protect information as it travels in and out of the model.

Question 3

5 layer design

1. Perimeter layer

Answer 3

The first layer of defense in depth is the perimeter layer. This layer includes some technologies that we’ve already explored, like usernames and passwords. Mainly, this is a user authentication layer that filters external access. Its function is to only allow access to trusted partners to reach the next layer of defense.

Question 4

5 layer design

2. The network layer

Answer 4

Second, the network layer is more closely aligned with authorization. The network layer is made up of other technologies like network firewalls and others.

Question 5

5 layer design

3. The endpoint layer

Answer 5

Endpoints refer to the devices that have access on a network. They could be devices like a laptop, desktop, or a server. Some examples of technologies that protect these devices are anti-virus software.

Question 6

5 layer design

4. The application layer

Answer 6

This includes all the interfaces that are used to interact with technology. At this layer, security measures are programmed as part of an application. One common example is multi-factor authentication. You may be familiar with having to enter both your password and a code sent by SMS. This is part of the application layer of defense.

Question 7

5 layer design

5. The data layer

Answer 7

And finally, the fifth layer of defense is the data layer. At this layer, we’ve arrived at the critical data that must be protected, like personally identifiable information. One security control that is important here in this final layer of defense is asset classification.

Like I mentioned earlier, information passes in and out of each of these five layers whenever it’s exchanged over a network. There are many more security controls aside from the few that I mentioned that are part of the defense in depth model. A lot of businesses design their security systems using the defense in-depth model. Understanding this framework hopefully gives you a better sense of how an organization’s security controls work together to protect important assets.