What does the term "Defense in Depth" refer to in information security?

The term "Defense in Depth" refers to an information security strategy that employs multiple layers of security controls to protect information and resources. This concept stems from the understanding that no single security measure is foolproof, and by incorporating a series of overlapping defenses, organizations can create a more robust security posture.

Each layer acts as a barrier to potential threats, making it more difficult for intruders to breach the system. For example, an organization might combine firewalls, intrusion detection systems, access controls, and physical security measures, so that if one layer fails, others are still in place to help protect the information.

This multi-faceted approach not only enhances overall security but also provides redundancy. If an attacker bypasses one layer, additional layers can still intercept or mitigate their actions. Thus, employing a Defense in Depth strategy significantly reduces the risk of successful attacks and data breaches, ensuring a higher level of security across the organization.