The three pillars of cybersecurity:
• Confidentiality – Keeping data private (only authorized users can access it).
Example: Encryption, passwords, access controls.
• Integrity – Ensuring data is accurate and unaltered.
Example: Digital signatures, file checksums.
• Availability – Ensuring data and systems are accessible when needed.
Example: Backups, redundancy, DDoS protection.
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2. Authentication, Authorization, and Accounting (AAA)
• Authentication – Verifying identity (e.g., username + password, biometrics, MFA).
• Authorization – Granting permissions (what the user can access/do).
• Accounting – Tracking user activity (logs, audits).
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3. Threats & Vulnerabilities
• Threat – Something that could cause harm (e.g., hacker, malware).
• Vulnerability – Weakness that can be exploited (e.g., unpatched software).
• Exploit – The actual method of attack.
• Risk = Threat × Vulnerability × Impact.
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4. Defense in Depth (Layered Security)
Security should not rely on one layer only.
• Physical Security – Locks, CCTV, guards.
• Network Security – Firewalls, VPN, IDS/IPS.
• Endpoint Security – Antivirus, patches, device encryption.
• Application Security – Secure coding, testing.
• Data Security – Encryption, backups.
• User Awareness – Training against phishing, social engineering.
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5. Security Controls
• Preventive (stop attacks) → firewalls, access controls.
• Detective (identify attacks) → IDS, monitoring, SIEM.
• Corrective (fix damage) → patches, backups, disaster recovery.
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6. Common Cyber Attacks
• Phishing (tricking users into giving info).
• Malware (virus, worm, trojan, ransomware).
• DDoS (overloading a service).
• Man-in-the-Middle (eavesdropping).
• SQL Injection & XSS (web app attacks).
• Zero-day Exploits (attacks on unknown vulnerabilities).
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7. Encryption & Cryptography
• Symmetric encryption – Same key for encryption/decryption (AES).
• Asymmetric encryption – Public/private key (RSA, ECC).
• Hashing – One-way fingerprint of data (SHA, MD5).
• Digital Certificates – Used in SSL/TLS for website security.
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8. Identity & Access Management (IAM)
• Principle of Least Privilege (PoLP) – Give only the access required.
• Zero Trust – “Never trust, always verify.”
• Multi-Factor Authentication (MFA) – Extra security layer.
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9. Incident Response
Steps when something goes wrong:
1. Preparation – Plans, training, backups.
2. Detection – Spot the incident (monitoring, alerts).
3. Containment – Limit the damage.
4. Eradication – Remove the threat.
5. Recovery – Restore systems.
6. Lessons Learned – Improve security.
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10. Compliance & Standards
• GDPR, HIPAA, PCI-DSS – Regulations for protecting data.
• ISO 27001, NIST, CIS – Security frameworks & best practices.
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✅ In short: Cybersecurity = protecting data + systems + people from threats using layers of defense, strong identity controls, and continuous monitoring.