Defense in depth is a strategy that leverages multiple security measures to protect an organization's assets. The thinking is that if one line of defense is compromised, additional layers exist as a backup to ensure that threats are stopped along the way.

Defense in depth addresses the security vulnerabilities inherent not only with hardware and software but also with people, as negligence or human error are often the cause of a security breach.

Today’s cyber threats are growing rapidly in scale and sophistication. Defense in depth is a comprehensive approach that employs a combination of advanced security tools to protect an organization's endpoints, data, applications, and networks.

The goal is to stop cyber threats before they happen, but a solid defense-in-depth strategy also thwarts an attack that is already underway, preventing additional damage from taking place.

Antivirus software, firewalls, secure gateways, and virtual private networks (VPNs) serve as traditional corporate network defenses and are certainly still instrumental in a defense-in-depth strategy.

More sophisticated measures, such as the use of machine learning (ML) to detect anomalies in the behavior of employees and endpoints, are now being used to build the strongest and most complete defense possible.