INTRODUCTION TO NETWORK SECURITY

2 THREATS AND VULNURABILITIES

NETWORK SECURITY DEVICES AND TECHNOLOGIES

NETWORK TRAFFIC ANALYSIS

CRYPTOGRAPHY AND NETWORK SECURITY

NETWORK SECURITY ANALYSIS AND FORENSIC

SECURING WIRELESS NETWORKS

ADVANCED TOPICS IN NETWORK SECURITY

Core concepts and design principles

DESIGN PRINCIPLES

Design principles in network security are fundamental guidelines to ensure that network infrastructures are protected from various threats. 

These principles help create robust systems that are resilient to attacks, maintain confidentiality, integrity, availability, and overall security. 

1. Defense in Depth

Implementing multiple layers of security controls so that if one layer fails, others still provide protection.

  • Examples: Firewalls, intrusion detection systems (IDS), encryption, access control lists (ACLs), and antivirus software.

2. Least Privilege

Users and systems should only be given the minimum level of access necessary to perform their tasks. This reduces the potential damage caused by accidental or malicious actions.

  • Examples: Limiting user permissions to only what is necessary, using role-based access control (RBAC), and applying the principle of least privilege to software and services.

3. Fail-Safe Defaults

Systems should be configured with secure default settings to minimize the risk of human error in configuration. By default, access should be denied, and security features should be enabled.

  • Examples: Disabling unused ports, enabling strong passwords by default, and enforcing secure protocols (e.g., HTTPS, SSH).

4. Separation of Duties

Critical functions should be split between multiple individuals or systems to prevent malicious activities and ensure accountability.

  • Examples: Requiring two or more administrators to perform certain tasks, like transferring funds or accessing sensitive data, which adds a layer of oversight.

5. Compartmentalization

Dividing the network into smaller, isolated segments to prevent lateral movement of attacks and limit exposure.

  • Examples: Using Virtual Local Area Networks (VLANs)

6. Redundancy and Fault Tolerance

Systems should be designed with redundancy to ensure continuous operation, even if one component fails. This prevents a single point of failure from compromising the network.

  • Examples: Implementing failover systems, load balancing, and backup power supplies.

7. Network Monitoring and Logging

Continuous monitoring of network traffic and logging of events are essential for identifying suspicious activities and responding to incidents promptly.

  • Examples: Using Security Information and Event Management (SIEM) systems, Intrusion Detection Systems (IDS), and logging access to sensitive data and resources.

8. Encryption

Sensitive data should be encrypted both in transit and at rest to protect it from unauthorized access and tampering.

  • Examples: Using Secure Socket Layer (SSL)/Transport Layer Security (TLS) for web traffic, encrypting databases and file systems, and employing end-to-end encryption for communications.

9. Patch Management

Keeping software and systems up to date with the latest security patches is crucial for preventing exploitation of known vulnerabilities.

  • Examples: Automating patching systems, applying regular updates, and using vulnerability scanners to identify outdated or vulnerable software.

10. Accountability and Auditing

All actions on the network should be logged and auditable to ensure accountability. In the event of a security breach, logs can help trace the source and determine the extent of the damage.

  • Examples: Implementing audit trails.

11. Security by Obscurity

Hiding system details to make it more difficult for attackers to understand the architecture and exploit weaknesses.

  • Examples: Changing default device names and settings, avoiding the publication of network diagrams, and obscuring internal addresses.

12. Strong Authentication

Implementing strong, multi-factor authentication (MFA) to ensure that only authorized users can access critical systems.

  • Examples: Requiring multi-factor authentication for accessing sensitive systems, integrating biometric authentication, and utilizing token-based systems.

13. Secure Configuration

Ensuring that devices, applications, and services are configured securely from the start and regularly reviewed for vulnerabilities.

  • Examples: Hardening systems, disabling unnecessary services, and applying best practice configurations (e.g., CIS benchmarks).

14. Continuous Improvement

Security is not a one-time effort. Constantly improving the network security posture based on new threats, vulnerabilities, and lessons learned.

  • Examples: Regular penetration testing, vulnerability assessments, and adapting security strategies to emerging technologies and threats.