Cybersecurity & Ethical Hacking
Summary Notes (2025 Edition)
Introduction & Core Concepts
What Is Cybersecurity?
Cybersecurity refers to the protection of computer
systems, digital networks, data, and online
infrastructure from malicious attacks, unauthorized
access, or damage. It focuses on maintaining the
confidentiality, integrity, and availability of information
in an increasingly digital world.
Cybersecurity safeguards both individuals and
organizations by preventing threats such as data
breaches, identity theft, ransomware, phishing, and
denial-of-service (DoS) attacks.
Why It Matters in 2025
With global digitization, billions of connected devices
and cloud systems are exchanging sensitive data every
second. Protecting this information is essential for:
National security
Business continuity
Financial integrity
Individual privacy
, Core Pillars of Cybersecurity (CIA Triad)
Element Definition Example
Confidentiality Only authorized users Encrypting customer
can access information. data in banking apps.
Integrity Data must remain Preventing tampering in
accurate and unchanged. hospital patient records.
Availability Systems must be Keeping e-commerce
accessible when needed. servers running 24/7.
Basic Terminology
Malware:
Any malicious software (viruses, worms, trojans).
Firewall:
Filters and blocks unwanted network traffic.
Encryption:
Converts data into an unreadable format for security.
Phishing:
Deceptive messages that trick users into giving personal
info.
Patch Management:
Regular updates to close software vulnerabilities.
Summary Notes (2025 Edition)
Introduction & Core Concepts
What Is Cybersecurity?
Cybersecurity refers to the protection of computer
systems, digital networks, data, and online
infrastructure from malicious attacks, unauthorized
access, or damage. It focuses on maintaining the
confidentiality, integrity, and availability of information
in an increasingly digital world.
Cybersecurity safeguards both individuals and
organizations by preventing threats such as data
breaches, identity theft, ransomware, phishing, and
denial-of-service (DoS) attacks.
Why It Matters in 2025
With global digitization, billions of connected devices
and cloud systems are exchanging sensitive data every
second. Protecting this information is essential for:
National security
Business continuity
Financial integrity
Individual privacy
, Core Pillars of Cybersecurity (CIA Triad)
Element Definition Example
Confidentiality Only authorized users Encrypting customer
can access information. data in banking apps.
Integrity Data must remain Preventing tampering in
accurate and unchanged. hospital patient records.
Availability Systems must be Keeping e-commerce
accessible when needed. servers running 24/7.
Basic Terminology
Malware:
Any malicious software (viruses, worms, trojans).
Firewall:
Filters and blocks unwanted network traffic.
Encryption:
Converts data into an unreadable format for security.
Phishing:
Deceptive messages that trick users into giving personal
info.
Patch Management:
Regular updates to close software vulnerabilities.
