🌐 COMPLETE SUMMARY OF THE CYBER SECURITY FUNDAMENTALS NOTE SECTION 1

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Cybersecurity is the practice of protecting computers, networks, data, and digital systems from attacks or unauthorized access. As the world becomes more connected—through smartphones, computers, household devices, and even medical and transportation systems—security risks continue to increase. Cybersecurity is essential for individuals, organizations, governments, and businesses to prevent data theft, financial loss, privacy breaches, and system disruption.

1. Introduction to Cybersecurity

Digital attacks can come from anywhere and can affect anyone—from students and teachers to large companies and government institutions. Cybersecurity helps prevent unauthorized access to accounts, protects sensitive information, and ensures safe communication. As online usage grows, so do risks, making cybersecurity a major topic in technology today.

2. The CIA Triad

Cybersecurity is built on a core model known as the CIA Triad:

🔐 Confidentiality

Ensures that private information is only accessed by authorized people.
Methods used include access control, encryption, passwords, and multi-factor authentication.

🛡️ Integrity

Ensures data remains accurate, unchanged, and trustworthy.
This is supported through backups, cryptography, logs, and digital signatures.

⚡ Availability

Ensures that systems and data are accessible when needed—even during attacks or power failures.
High availability is maintained through redundancy, cloud infrastructure, system updates, and disaster recovery plans.
Threats include DDoS attacks, ransomware, and hardware failures.

3. Physical Security

Physical security protects the physical components of the digital world—buildings, hardware, and people.
A cyberattack can be launched simply by walking into a server room or tampering with a device.
Physical security involves:

  • Access control (IDs, biometrics, locks)

  • Surveillance (CCTV, alarms, guards)

  • Secure facilities

  • Environmental protections

  • Proper equipment handling and disposal

Without physical security, even the strongest digital defenses can fail.

4. Data Breaches & Cyber Crimes

A data breach occurs when unauthorized individuals gain access to private information such as passwords, bank details, credit card numbers, or company records.
Breaches can happen:

  • By accident (human error)

  • Through intentional insider actions

  • From targeted external attacks

  • Due to lost or stolen devices

  • Through phishing, malware, or exploiting vulnerabilities

Data breaches lead to financial loss, reputational damage, legal consequences, and identity theft.

Cybercrime

Cybercrime includes illegal activities done using computers or networks.
Common examples:

  • Phishing

  • Identity theft

  • Ransomware attacks

  • Financial fraud

  • Copyright infringement

  • Crypto-jacking

  • Data theft

  • Selling illegal items online

Cybercriminals target both individuals and organizations for profit, espionage, revenge, or challenge.

5. Computer Viruses & Antivirus Software

🦠 Computer Viruses

A virus is a type of malware designed to spread across systems, damage files, slow devices, or steal information.
Common signs of infection:

  • Slow system performance

  • Pop-up windows

  • Programs closing by themselves

  • Accounts logging out unexpectedly

  • System crashes

  • Mass emails being sent without permission

  • Browser homepage changes

Viruses spread through infected files, USB drives, email attachments, unverified downloads, torrent sites, malicious ads, and outdated systems.

🛡️ How Antivirus Works

Antivirus software detects, blocks, and removes malware using:

  • Signature detection

  • Generic detection

  • Heuristic (behavior-based) detection

Antiviruses must be updated frequently to stay effective. They quarantine or delete harmful files, and users should routinely scan their systems, especially new downloads and email attachments.

6. The Dark Web & Deep Web

The internet is divided into three layers:

🌍 Surface Web

The visible part of the internet accessible through regular search engines.

🔒 Deep Web

Content not indexed by search engines—email accounts, academic databases, company portals, medical records, etc.

🕶️ Dark Web

A hidden part of the deep web that requires special tools like Tor, I2P, or Freenet to access.
It uses onion routing for anonymity.
The dark web is used for both good and bad:

Legal uses:

  • Anonymous communication

  • Activism

  • Research

  • Journalism

Illegal uses:

  • Selling drugs, weapons, stolen data

  • Illegal pornography

  • Cybercrime markets

  • Hacking services

Because of its anonymity, the dark web is dangerous for untrained users. Extra security precautions are required when accessing it.

7. Cyberattacks

A cyberattack is an attempt to access, alter, steal, or destroy digital systems or data. Attackers include hackers, criminal groups, insider threats, nation-state actors, and hacktivists.

Motivations include:

  • Financial gain

  • Political goals

  • Revenge

  • Curiosity or challenge

Attackers target:

  • Financial systems

  • Personal data

  • Government networks

  • Critical infrastructure

  • Intellectual property

Common cyberattack methods:

  • Malware (virus, worm, trojan, ransomware, spyware)

  • Social engineering (phishing, spear-phishing, BEC scams)

  • DoS and DDoS attacks

  • Account compromise

  • Man-in-the-middle attacks

  • Zero-day exploits

  • Website takeover or disruption

Cyberattacks can cause massive financial losses, system downtime, identity theft, service disruption, or permanent data loss.

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