Cyber Security Domains

1. Network Security

What it protects:

• Computer networks
• Routers
• Switches
• Firewalls
• Data traveling between devices

Why it matters:

If someone breaks into a network, they can access everything connected to it.

Common Tools:

• Firewalls
• Intrusion Detection Systems (IDS)
• Virtual Private Networks (VPN)

Simple Firewall Example (Conceptual)

# Block incoming traffic on port 23 (Telnet)
iptables -A INPUT -p tcp --dport 23 -j DROP

This command blocks insecure Telnet traffic.

2. Application Security

What it protects:

• Websites
• Mobile apps
• Software programs

Why it matters:

Applications often interact with users and databases. If insecure, they can be exploited.

Example: Secure Login (Basic PHP Example)

$stmt = $conn->prepare("SELECT * FROM users WHERE username = ? AND password = ?");
$stmt->bind_param("ss", $username, $password);
$stmt->execute();

This prevents SQL Injection by using prepared statements.

3. Information Security (InfoSec)

What it protects:

• Data (digital and physical)
• Sensitive information
• Confidential files

Core Principle: CIA Triad

• Confidentiality – Only authorized users can see data
• Integrity – Data cannot be altered improperly
• Availability – Data is accessible when needed

Example:

Encrypting files to protect confidentiality.

# Encrypt a file using OpenSSL
openssl enc -aes-256-cbc -salt -in file.txt -out file.enc

4. Cloud Security

What it protects:

• Cloud storage
• Cloud applications
• Cloud servers

Examples of cloud providers:

• Amazon Web Services
• Microsoft Azure
• Google Cloud

Why it matters:

Many businesses now store data in the cloud instead of physical servers.

5. Endpoint Security

What it protects:

• Laptops
• Smartphones
• Desktops
• Tablets

Each device connected to a network is called an endpoint.

If one infected laptop connects to a company network, the whole company could be at risk.

6. Identity and Access Management (IAM)

What it protects:

• User identities
• Login systems
• Access control

Example: Role-Based Access Control (RBAC)

def check_access(role):
    if role == "admin":
        return "Full Access"
    elif role == "user":
        return "Limited Access"
    else:
        return "No Access"

Only certain roles get full permissions.

7. Operational Security (OPSEC)

What it protects:

• Internal processes
• Security procedures
• How data is handled

Example:

• Limiting who can access sensitive documents
• Using strong internal policies

8. Disaster Recovery & Business Continuity

What it protects:

• Business operations after attacks
• Recovery from ransomware
• System failures

Includes:

• Backups
• Recovery plans
• Incident response plans

9. Cyber Threat Intelligence

What it does:

• Studies attackers
• Tracks hacking groups
• Analyzes attack patterns

Example:

The ransomware WannaCry helped security experts understand global vulnerabilities.

10. Governance, Risk & Compliance (GRC)

What it focuses on:

• Security policies
• Legal requirements
• Industry standards

Examples of security standards:

• International Organization for Standardization (ISO 27001)
• National Institute of Standards and Technology (NIST Framework)

These guide organizations on how to manage cybersecurity properly.

How These Domains Work Together

Imagine a company:

• Network Security protects internal communication
• Application Security protects the website
• Cloud Security protects cloud storage
• IAM controls who logs in
• GRC ensures legal compliance
• Disaster Recovery ensures business survival after an attack

They are all connected.

Compilation of All Code Blocks (Combined)

Below is every example combined into one single block as requested:

# ------------------------
# Firewall Example (Network Security)
# ------------------------
iptables -A INPUT -p tcp --dport 23 -j DROP


# ------------------------
# Encryption Example (Information Security)
# ------------------------
openssl enc -aes-256-cbc -salt -in file.txt -out file.enc

// ------------------------
// Secure Login (Application Security)
// ------------------------
$stmt = $conn->prepare("SELECT * FROM users WHERE username = ? AND password = ?");
$stmt->bind_param("ss", $username, $password);
$stmt->execute();

# ------------------------
# Role-Based Access Control (IAM)
# ------------------------
def check_access(role):
    if role == "admin":
        return "Full Access"
    elif role == "user":
        return "Limited Access"
    else:
        return "No Access"