What is the principle of defense in depth?

The principle of defense in depth involves employing multiple layers of security controls to protect information and technology assets. This strategy is based on the idea that if one layer of security is breached, additional layers will continue to provide protection. By integrating various security measures such as firewalls, intrusion detection systems, anti-virus software, and access control mechanisms, organizations create a more resilient defense against potential threats.

This multi-layered approach reduces the likelihood of a successful attack because attackers would have to bypass multiple barriers to access sensitive data or systems. It also helps in mitigating risks from different vectors, including external threats and internal vulnerabilities. For example, while a robust firewall might prevent unauthorized access from the internet, additional measures like user authentication, encryption, and network segmentation provide further defense to protect data from various types of attacks.

Thus, the essence of defense in depth is to provide a comprehensive security posture that combines various techniques and technologies to enhance overall security, making it much harder for malicious actors to succeed.