What does the term "defense in depth" refer to?

The term "defense in depth" refers to a security strategy that employs multiple layers of defense to protect an organization’s information and systems. This approach recognizes that no single security measure is sufficient to address all potential threats. By implementing various safeguards at different levels, such as physical security, authentication mechanisms, firewalls, intrusion detection systems, and encryption, organizations can create a robust security posture that can mitigate risks more effectively.

In contrast, relying solely on a single-layer security system would leave multiple vulnerabilities, as a determined attacker might find ways to bypass that one layer. Similarly, relying exclusively on one security tool fails to cover the diverse types of threats that can emerge. Moreover, using only firewalls provides limited protection, as firewalls are just one part of a comprehensive security strategy. Overall, the concept of "defense in depth" emphasizes a multi-faceted approach that strengthens overall security by addressing various points of potential exposure.