What network security concept requires multiple layers of security controls to be placed throughout an IT infrastructure, which improves the security posture of an organization to defend against malic

Security through obscurity relies on hiding system details to prevent attacks rather than layering controls, and is widely considered an insufficient and unreliable security strategy.

A Host-Based Intrusion Detection System (HIDS) is a specific single-layer monitoring tool installed on individual hosts, not a multi-layered security strategy.

Defense in depth applies multiple overlapping security controls - such as firewalls, IDS/IPS, endpoint protection, access controls, and encryption - at different layers of the IT infrastructure. This approach ensures that a single point of failure does not compromise the entire environment, because an attacker must defeat each successive layer. The concept originates from military strategy and is codified in frameworks such as NIST SP 800-53 and the CIS Controls.

A Network-Based Intrusion Detection System (NIDS) monitors network traffic at a single vantage point and is one component of a layered strategy, not the strategy itself.