Cyber security threats

Welcome to the World of Digital Defense!

Hey there! Ready to dive into one of the most exciting and important parts of Computer Science? This chapter is all about understanding the bad guys—or rather, the cyber security threats—that exist online. Think of this as learning how to build a strong digital fortress! 🏰

Don't worry if some of these terms sound scary. We will break down every attack into simple, clear steps. By the end, you'll not only know what these threats are but also how to spot them and protect yourself and others.

Let's get started on securing the digital future!

1. Understanding the Concept of Cyber Security Threats

A Cyber Security Threat is anything that has the potential to harm a computer system, network, or the data stored on it. These threats usually try to achieve one of three things (we call this the CIA Triad, which you’ll study more later):

• Steal or access confidential data (Confidentiality)
• Change or destroy data (Integrity)
• Stop users from accessing the system (Availability)

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2. Malware: The Digital Illness

Malware is short for Malicious Software. It’s any program or code designed specifically to cause damage, gain unauthorised access, or disrupt system operation.

Key Types of Malware You Need to Know:

1. Viruses

A virus is a type of malware that needs a host program (like a document or an application) to attach itself to. It requires a user action (like opening the infected file) to run, and it aims to replicate and spread to other files and systems.

• Analogy: Just like a biological virus, it needs a host cell (a program) to activate and multiply.

2. Trojans (Trojan Horses)

A Trojan disguises itself as harmless or legitimate software (like a game or utility), tricking the user into installing it. Once installed, it carries out malicious actions in the background, such as opening a backdoor for attackers.

3. Spyware & Keyloggers

This software secretly observes and records the user’s activity without their knowledge. Its main goal is to capture sensitive information.

• Example: A type of spyware called a keylogger records every single keystroke you make (passwords, messages, credit card numbers).

4. Ransomware

Ransomware encrypts (locks) files and data on a system, making them completely inaccessible. The attacker then demands a ransom (payment, usually in cryptocurrency) in exchange for the decryption key.

• Analogy: It’s like a digital kidnapper holding your data hostage.

5. Adware

Software that automatically displays or downloads unwanted advertisements on your screen, often slowing down the system and generating revenue for the author.

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3. Social Engineering: The Human Weakness

Social Engineering is the art of manipulating people into giving up confidential information or performing actions that compromise security. Attackers target human psychology rather than software flaws.

Key Social Engineering Techniques:

1. Phishing

Attackers send fraudulent messages (usually emails) pretending to be from a trustworthy organisation (like a bank or online store). The message contains a link to a fake website designed to steal login credentials or personal data.

2. Blagging (Pretexting)

The act of creating an invented scenario or fake identity (a pretext) to persuade a victim to disclose confidential information or grant unauthorised access that they would not otherwise reveal.

3. Shouldering (Shoulder Surfing)

Direct observation where an attacker looks over someone’s shoulder (or uses binoculars/cameras) while they type in their PIN, password, or security code at an ATM, keyboard, or terminal.

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4. Brute Force Attacks: The Persistent Guesser

A Brute Force Attack is a method used to gain access to an account or encrypted data by systematically trying every possible combination of passwords or encryption keys until the correct one is found.

Step-by-Step Process:

1. The attacker targets a specific login page (e.g., your email).
2. They use automated software (a "bot").
3. The software rapidly tries millions of combinations: "a", "aa", "aab", "123456", "password", etc.

This attack relies purely on computer processing power and speed.

How to Defend Against It: Longer, complex passwords with uppercase letters, numbers, and symbols exponentially increase the number of combinations, making brute force attacks practically impossible in a reasonable time frame.

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5. Denial of Service (DoS / DDoS): The Digital Traffic Jam

A Denial of Service (DoS) attack is designed to make a machine or network resource unavailable to its intended users by overloading the system with flood requests.

DoS vs. DDoS:

1. DoS (Denial of Service): The attack originates from a single computer system.

2. DDoS (Distributed Denial of Service): The attack is launched simultaneously from many compromised systems, known as a botnet (a network of infected computers controlled remotely by the attacker).

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6. Data Interception and Packet Sniffing

When data travels across a network, it is split into packets. Malicious users can use packet sniffers to intercept and read data packets in transit.

The Risk: If data is sent unencrypted (e.g., over unsecured public Wi-Fi), attackers can read passwords and sensitive communications in plain text.

Defence Hint: Always ensure secure protocols like HTTPS are used to encrypt data during transmission.

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7. SQL Injection

SQL Injection occurs when an attacker inputs malicious SQL code into an application's user input field (such as a login box or search bar).

If the application lacks proper input validation, it passes this malicious input directly to the database interpreter, allowing the attacker to bypass authentication, view private database records, modify data, or delete tables.

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8. Vulnerabilities, Policies, and Testing

Threats often succeed because of underlying vulnerabilities in system configuration or human behaviour.

Common Vulnerabilities:

• Weak & Default Passwords: Predictable or factory-set passwords leave systems open to automated guessing.
• Unpatched Software: Failing to install security updates leaves known software vulnerabilities unpatched.
• Removable Media: Connecting infected USB flash drives or external drives can automatically introduce malware to an otherwise isolated network.
• Misconfigured Access Rights: Giving users greater permissions than necessary allows unauthorised access if an account is compromised.
• Lack of Training: Employees unaware of social engineering schemes remain vulnerable to manipulation.

Identifying Vulnerabilities: Penetration Testing

Penetration Testing (or ethical hacking) is the process of deliberately attempting to gain unauthorised access to a computer system or network with permission, in order to identify vulnerabilities and weaknesses before malicious attackers can exploit them.