Course 10 - Network Security Fundamentals | Episode 7: Implementing Defense in Depth, Data Integrity, and Zero Trust
Update: 2025-11-28
Description
In this lesson, you’ll learn about:
You can listen and download our episodes for free on more than 10 different platforms:
https://linktr.ee/cybercode_academy
- Defense in Depth (DiD) and layered security controls
- Data integrity, backup policies, and encryption best practices
- Securing voice and email communications
- Social engineering and vishing defense
- PKI-based email protection (PGP, S/MIME)
- Zero Trust Networking (ZTN) architecture and IAM principles
- Physical Controls: Locks, cameras, facility access controls
- Administrative Controls: Policies, procedures, user awareness training
- Perimeter Controls: Firewalls, filtering devices
- Internal Network Controls: Segmentation, monitoring, endpoint security
- Goal: an attacker must successfully bypass multiple layers at the same time, reducing overall risk.
- Data must stay complete, accurate, and accessible.
- Backup policies must consider the entire data lifecycle.
- Follow regulatory retention requirements (e.g., financial records retained for 7 years in certain industries).
- Use reliable storage media and ensure off-site storage for disaster recovery.
- Employ both:
- On-site backups for fast recovery
- Off-site backups for catastrophic events
- Plan for long-term data growth.
- Confidential data should be encrypted using strong symmetric algorithms such as AES-256.
- Protects against physical theft, insider threats, and unauthorized access.
- VoIP (Voice over IP)
- POTS (Plain Old Telephone System)
- Mobile communications
- Man-in-the-Middle (MitM) attacks
- Caller ID spoofing
- “Phone phreaking” and unauthorized system access
- Social engineering and vishing attacks
- Encrypt voice traffic where possible.
- Disable unnecessary features on phone systems.
- Change all default passwords and device settings.
- Use network segmentation (VLANs/subnets) to isolate voice systems from the main LAN.
- Users with sensitive communications should use encrypted apps such as Signal.
- PGP / GPG / OpenPGP
- S/MIME (Secure / Multipurpose Internet Mail Extensions)
- Opportunistic TLS for encrypting SMTP connections when possible.
- SPF (Sender Policy Framework) to validate legitimate email senders.
- Anti-spam and anti-phishing filters (e.g., Bayesian filtering).
- User training via phishing simulations to strengthen human defense.
- “Never trust, always verify.”
- Assume an attacker may already be inside the network.
- Strict verification of every user and device before access is granted.
- Network segmentation using VLANs and subnets to reduce lateral movement.
- Identification of the “protect surface” — the most critical data and systems.
- Strong use of AAA principles:
- Authentication (verify identity)
- Authorization (grant the minimum required access)
- Accounting/Auditing (log all actions)
- Reduces reliance on perimeter-only defenses.
You can listen and download our episodes for free on more than 10 different platforms:
https://linktr.ee/cybercode_academy
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