## What is Defense in Depth?
- A cybersecurity strategy using multiple security layers.
- Protects data, systems, and networks.
- Ensures no single point of failure.
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## Key Principles of Defense in Depth
1. **Layered Security**
2. **Redundancy**
3. **Diversity of Controls**
4. **Proactive and Reactive Measures**
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## Layered Security
- Implement multiple, independent security layers.
- Each layer addresses different threats.
- Enhances overall protection.
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## Redundancy
- Failover mechanisms in place.
- Backup systems to maintain security.
- Prevents exposure if one layer fails.
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## Diversity of Controls
- Use various defense types: firewalls, encryption, authentication.
- Avoid reliance on a single technology.
- Reduces vulnerability to specific attacks.
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## Proactive and Reactive Measures
- Combine prevention with detection and response.
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## The Layers of Defense in Depth
1. Data Layer
2. Application Layer
3. Host Layer
4. Network Layer
5. Perimeter Layer
6. Physical Layer
7. Policies, Procedures, and Awareness Layer
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## Data Layer
- **Key Measures:**
- Data encryption (at rest and in transit).
- Access controls (RBAC, ABAC).
- Backup and recovery solutions.
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## Application Layer
- **Key Measures:**
- Secure coding practices.
- Input validation to prevent SQL injection and XSS.
- Web Application Firewalls (WAFs).
- **Advanced Measures:**
- Data Loss Prevention (DLP) Systems.
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## Host Layer
- **Key Measures:**
- Antivirus and anti-malware tools.
- Operating system hardening.
- **Advanced Measures:**
- File Integrity Monitoring (FIM).
- Endpoint Detection and Response (EDR) solutions.
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## Network Layer
- **Key Measures:**
- Firewalls.
- Network segmentation.
- Virtual Private Networks (VPNs).
- **Advanced Measures:**
- Intrusion Detection/Prevention Systems (IDS/IPS).
- DNS security (e.g., DNSSEC).
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## Perimeter Layer
- **Key Measures:**
- Perimeter firewalls and proxies.
- Demilitarized Zones (DMZs) for public-facing services.
- **Advanced Measures:**
- DDoS mitigation solutions.
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## Physical Layer
- **Key Measures:**
- Access controls (keycards, biometrics).
- Surveillance systems (CCTV).
- Environmental controls (fire suppression).
- **Additional Measures:**
- Secure hardware disposal processes.
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## Policies, Procedures, and Awareness Layer
- **Key Measures:**
- Security awareness training for employees.
- Incident response and disaster recovery plans.
- Regular audits and compliance checks.
- **Additional Measures:**
- Defined security policies and governance frameworks.
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## Conclusion
- Defense in Depth offers a holistic IT security approach.
- Combines technical, procedural, and human measures.
- Enhances resilience against diverse cyber threats.