Network Security Fundamentals

Network security involves protecting data, resources, and infrastructure from unauthorized access, misuse, or theft.

Security Threats

Common Attack Types

Malware: Malicious software including viruses, worms, trojans, and ransomware.

Phishing: Social engineering attacks that trick users into revealing sensitive information.

Man-in-the-Middle (MitM): Attackers intercept communication between two parties.

Denial of Service (DoS/DDoS): Overwhelming a system with traffic to make it unavailable.

SQL Injection: Exploiting vulnerabilities in database queries to access or manipulate data.

Zero-Day Exploits: Attacks targeting previously unknown vulnerabilities.

Security Measures

Firewalls

Firewalls monitor and control network traffic based on security rules.

• Packet filtering: Examines packet headers
• Stateful inspection: Tracks connection states
• Application-level gateways: Inspects application data
• Next-generation firewalls: Combines multiple security features

Encryption

Encryption protects data confidentiality by converting information into unreadable formats.

Symmetric encryption: Same key for encryption and decryption (AES, DES)

Asymmetric encryption: Public/private key pairs (RSA, ECC)

SSL/TLS: Secures web communications (HTTPS)

Authentication & Authorization

Authentication: Verifying user identity

• Passwords
• Multi-factor authentication (MFA)
• Biometrics
• Certificates

Authorization: Controlling access to resources

• Role-based access control (RBAC)
• Access control lists (ACLs)
• Principle of least privilege

Virtual Private Networks (VPNs)

VPNs create encrypted tunnels for secure communication over public networks.

Benefits:

• Data encryption
• IP address masking
• Secure remote access
• Bypass geographical restrictions

Intrusion Detection and Prevention

IDS (Intrusion Detection System): Monitors network traffic for suspicious activity

IPS (Intrusion Prevention System): Actively blocks detected threats

Security Best Practices

1. Keep software and systems updated
2. Use strong, unique passwords
3. Enable multi-factor authentication
4. Regular security audits and assessments
5. Employee security training
6. Data backup and disaster recovery plans
7. Network segmentation
8. Principle of least privilege
9. Monitor and log network activity
10. Incident response planning