What does 'Defense in Depth' principally focus on?

'Defense in Depth' principally focuses on layering multiple controls to protect information systems. This approach is based on the idea that no single security measure is sufficient on its own. Instead, by employing a comprehensive strategy that includes various types of defenses at different layers, organizations can create a more robust security posture. This multi-layered strategy can encompass a mix of physical security, technical security (like firewalls and intrusion detection systems), and administrative controls (such as policies and training).

Choosing to layer multiple controls allows for redundancy, meaning that even if one layer fails or is bypassed, additional layers continue to provide protection. This is particularly crucial in addressing various types of threats, as attackers might exploit different vulnerabilities. By having overlapping controls, the chances of successfully defending against attacks increase significantly, illustrating that a proactive and layered approach is a key principle in effective information security management.