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Common Security Concepts

Understanding fundamental security concepts is essential for anyone starting their cybersecurity journey. This page covers the core principles and terminology you'll encounter throughout your learning.

CIA Triad

The CIA Triad is the foundation of information security:

  • Confidentiality - Ensuring data is accessible only to authorized individuals
  • Integrity - Maintaining accuracy and trustworthiness of data
  • Availability - Ensuring systems and data are accessible when needed

Authentication vs Authorization

Concept Description Example
Authentication Verifying identity (Who are you?) Username/password login
Authorization Verifying permissions (What can you do?) Role-based access control

Defense in Depth

A layered security approach where multiple security controls protect assets:

  1. Physical Security - Locks, badges, cameras
  2. Network Security - Firewalls, IDS/IPS, segmentation
  3. Host Security - Antivirus, EDR, patching
  4. Application Security - Input validation, secure coding
  5. Data Security - Encryption, DLP, access controls

Principle of Least Privilege

Users and systems should only have the minimum permissions necessary to perform their tasks.

Best Practice

Always start with zero permissions and grant only what's explicitly required.

Common Security Terminology

Term Definition
Vulnerability A weakness that can be exploited
Threat A potential danger to assets
Risk Likelihood × Impact of a threat exploiting a vulnerability
Exploit Code or technique that takes advantage of a vulnerability
Attack Vector The path an attacker uses to gain access
Attack Surface Total sum of vulnerabilities in a system

Types of Security Controls

By Function

  • Preventive - Stop attacks before they happen (firewall rules)
  • Detective - Identify attacks in progress (SIEM alerts)
  • Corrective - Fix issues after an attack (patch management)
  • Deterrent - Discourage attackers (warning banners)

By Implementation

  • Technical - Software/hardware controls (encryption)
  • Administrative - Policies and procedures (security training)
  • Physical - Physical barriers (security guards)

Zero Trust Model

"Never trust, always verify" - A security model that:

  • Verifies every user and device
  • Limits access with least privilege
  • Assumes breach and minimizes blast radius

Common Attack Types

Attack Description
Phishing Social engineering via fraudulent emails
SQL Injection Inserting malicious SQL into queries
XSS Injecting scripts into web pages
DDoS Overwhelming systems with traffic
Man-in-the-Middle Intercepting communications
Brute Force Systematically trying all passwords

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