Introducing Defense in Depth

In information security, Defense in Depth is a collaborative use of multiple security countermeasures to protect an enterprise against targeted attacks. We can define targeted attacks, as attacks that are against the confidentiality, integrity, and availability of a system/service.

Defense in Depth is also called the layered-based approach and ideally, each layer protects against a specific type of threat. When these layers are combined together, they act as a shield that protects against most attacks.

While we are talking about layers, let's look at some layers:

• Firewalls
• Antivirus
• Intrusion prevention systems (IPS) / Intrusion detection systems (IDS)
• Virtual private networks (VPN)
• Vulnerability scanners
• Multi-Factor authentication (MFA)
• Encryption
• Hashing
• Web application firewall
• Authentication and authorization
• Demilitarized zones (DMZ)

So overall, if we observe, each layer protects against a specific type of threat and together when these layers are combined and architected...