Information and Communication Technology | Threats and Security on the Internet

Chapter Notes: Threats and Security on the Internet

Hey everyone! Welcome to one of the most important topics in ICT. We use the Internet every day, but have you ever thought about the dangers lurking online? In this chapter, we'll explore the common threats you might face and, more importantly, learn how to build a digital fortress to protect yourself and your information. Think of yourself as becoming a cybersecurity expert for your own digital life! It's a super useful skill to have.

Part 1: The Dangers - Common Network Security Threats

The Internet is like a massive city. Most people are friendly, but there are also digital pickpockets and vandals. Let's learn to spot them. These threats often come in the form of malicious software, also known as malware.

Malicious Software (Malware)

Virus

A computer virus is a piece of code that attaches itself to a program or file. When you run that program, the virus activates and spreads to other files on your computer. It needs a human action (like opening a file) to spread.

Analogy: A virus is like the human flu. It needs to travel from person to person (or file to file) and can't spread on its own.

Worm

A worm is more independent than a virus. It's a standalone program that can copy itself and spread through a network without any human help. It exploits security weaknesses to travel from one computer to another.

Analogy: Think of a worm tunnelling through a network of computers all by itself, causing traffic jams and damage as it goes.

Trojan Program (or Trojan Horse)

A Trojan is malware disguised as a legitimate, useful program (like a game or a utility). When you install it, it secretly creates a 'backdoor' on your computer, allowing attackers to gain unauthorised access, steal your data, or install other malware.

Analogy: It's named after the famous Greek story of the Trojan Horse. The Greeks gave a giant wooden horse as a gift, but it was secretly filled with soldiers. A Trojan program looks like a gift, but it's hiding something dangerous inside.

Spyware

As the name suggests, spyware's job is to spy on you! It secretly installs on your computer and collects information, such as your browsing habits, login details, and even keystrokes (this is called keylogging). This information is then sent to an attacker.

Ransomware

This is a particularly nasty type of malware. Ransomware encrypts (locks) all the files on your computer, making them completely unusable. The attackers then demand a ransom payment (usually in cryptocurrency) in exchange for the key to unlock your files.

Quick Review: Malware Types

• Virus: Attaches to files, needs you to run the file to spread.

• Worm: Spreads across networks by itself.

• Trojan: Disguises itself as useful software to trick you.

Attacks and Intrusions

Unauthorised Access (Hacking)

This is when someone gains access to a computer system, network, or data without permission. They might do this to steal information, cause damage, or just for the challenge.

Interception (Eavesdropping)

This is the digital equivalent of listening in on someone's private conversation. Attackers can intercept data as it travels over a network, especially an unsecured one like public Wi-Fi. They could capture your passwords, credit card numbers, and messages.

Denial of Service (DoS) Attack

The goal of a DoS attack is to make a website or online service unavailable to its real users. The attacker floods the target server with so much traffic that it gets overwhelmed and either crashes or becomes incredibly slow.

Analogy: Imagine a thousand fake customers rushing into a small shop at once, all asking pointless questions. The real customers can't get in or get any service because the staff are completely overwhelmed.

Intrusion via Dynamic Web Pages

Modern websites are complex. Sometimes, there are bugs or vulnerabilities in the website's code. Attackers can exploit these weaknesses to force the website to do things it shouldn't, like revealing sensitive user data from its database.

Key Takeaway for Part 1:
Threats are varied, from malware that infects your computer (like viruses and ransomware) to attacks that target online services (like DoS attacks). Being aware of what they are is the first step to avoiding them!

Part 2: The Defences - How to Improve Network Security

Now for the good news! We have many powerful tools and techniques to defend against these threats. Building good security is all about creating multiple layers of defence.

Software and Settings

Anti-virus Software

This is essential software that scans your computer for known viruses, worms, spyware, and other types of malware. It can detect and remove threats. It's crucial to keep it updated so it knows how to spot the latest malware.

Firewall

A firewall acts as a security guard for your network. It monitors all incoming and outgoing network traffic and decides whether to allow it or block it based on a set of security rules. It can be a piece of software on your computer or a hardware device (like in your home router).

Analogy: A firewall is like the bouncer at a club. It checks everyone's ID at the door and only lets authorised people in, keeping troublemakers out.

Secure Browser Settings

Your web browser has many built-in security features. You can use them to block pop-ups, stop websites from tracking you, and warn you about dangerous websites. Always check for a padlock icon and "https://" in the address bar before entering sensitive information.

Access Control

Don't worry, this sounds more complex than it is! Access control is simply about managing who can access information and what they are allowed to do with it.

Authentication vs. Authorisation

These two words are often confused, but they are different!

• Authentication is the process of proving you are who you say you are. (Example: Logging in with your username and password).

• Authorisation is the process of determining what you are allowed to do after you've been authenticated. (Example: A regular student can read school announcements, but only a teacher can post them).

Access and User Right Control

This is putting authorisation into practice. On a school network, for example, system administrators set user rights to control which files and folders different users (like students, teachers, and staff) can read, write, or delete.

Securing Your Connection

Wireless Security Protocols (e.g., WPA)

Ever wondered why you need a password for your home Wi-Fi? It's to encrypt the data! Modern routers use protocols like WPA (Wi-Fi Protected Access) or WPA2/3 to scramble the wireless signal, so neighbours or people outside can't eavesdrop on what you're doing online.

Virtual Private Network (VPN)

A VPN creates a secure, encrypted "tunnel" for your Internet traffic. This is especially useful on public Wi-Fi. Even if someone intercepts your data, they can't read it because it's encrypted. It also hides your real location (IP address), adding a layer of privacy.

Key Takeaway for Part 2:
A strong defence uses layers: anti-virus to fight malware, a firewall to guard the network entrance, proper access controls to limit permissions, and encryption (like WPA and VPNs) to protect data in transit.

Part 3: Protecting Your Privacy

Security is about protecting your devices and data from harm. Privacy is about controlling who gets to see your personal information. Let's look at threats to your privacy and how to protect it.

Common Privacy Threats

Phishing

Phishing is a trick used by attackers to steal your personal information, like passwords or credit card numbers. They send you an email or message that looks like it's from a real company (like a bank or a social media site). The message contains a link to a fake website that looks identical to the real one. When you enter your login details on the fake site, the attackers capture them.

Memory Aid: They are "fishing" for your information, hence the name "phishing".

Spamming and Junk Mails

Spam is just unwanted, unsolicited email sent in bulk. While often just annoying advertisements, spam can also be dangerous. It's a common way to deliver phishing attacks and malware.

Did you know? Hacking and interception, which we discussed earlier, are also major privacy threats because they can expose your private data and communications.

Ways to Maintain Privacy

Use Strong Passwords

This is one of the easiest and most effective things you can do!

• Length is key: Aim for at least 12 characters.

• Mix it up: Use a combination of uppercase letters, lowercase letters, numbers, and symbols.

• Be unique: Don't use the same password for multiple important accounts.

Anonymity

Sometimes you might want to browse the web without revealing your identity or location (your IP address). Tools like VPNs and anonymous browsers can help you achieve this, making it harder for websites and advertisers to track you.

Important Note: Unauthorised access to computers (hacking) is a serious crime with legal consequences, including fines and imprisonment. Always respect others' digital property.

Key Takeaway for Part 3:
Be skeptical of unexpected emails (phishing and spam), use strong, unique passwords for your accounts, and understand that you have tools to protect your online anonymity.

Part 4: The Secret Code - Encryption and Secure Transactions

How can you shop online or use online banking safely? The answer is encryption. Encryption is the process of converting data (plaintext) into a scrambled, unreadable format (ciphertext). Only someone with the correct 'key' can unscramble it.

Public and Private Key Encryption

This is a clever system that uses two related keys: a public key and a private key. Don't worry if this seems tricky at first, the analogy makes it simple!

• Your Public Key can be shared with everyone. It can only be used to lock (encrypt) messages.

• Your Private Key is kept completely secret by you. It is the only key that can unlock (decrypt) messages locked by your public key.

Analogy: Imagine you have a special padlock (your public key) that you give copies of to all your friends. Anyone can use that padlock to lock a box and send it to you. But only you have the one-of-a-kind key (your private key) that can open that padlock.

This system is used by organisations like the Hong Kong Public Key Infrastructure (PKI) to issue digital certificates and enable secure communications.

A simple rule: The longer the encryption key (measured in bits, like 128-bit or 256-bit), the harder it is to crack, and the more secure the encryption is.

Security in E-Commerce (Online Shopping)

Secure Sockets Layer (SSL) and HTTPS

Have you ever noticed the padlock icon in your browser's address bar, or that some web addresses start with https:// instead of http://? The 'S' stands for 'Secure'. This means the website is using SSL (or its modern successor, TLS) to create an encrypted connection between your browser and the website's server. All data sent back and forth, like your credit card number, is scrambled and protected from eavesdroppers.

Digital Certificates

How does your browser know that the website you're visiting is actually your bank and not a fake phishing site? The website presents a Digital Certificate to your browser. This certificate is like a digital passport, issued by a trusted third party (a Certificate Authority), that proves the identity of the website owner. Your browser checks this certificate to make sure it's valid and that you're connected to the real site.

Digital Signatures

A digital signature is used to verify the authenticity and integrity of a digital document. It proves two things:

1. The document was really sent by the person who claims to have sent it.

2. The document has not been altered since it was signed.

It works using the sender's private key to 'sign' the document and their public key to verify the signature.

Other Security Measures in Transactions

To make transactions even more secure, many services use methods that prove your identity in different ways:

• Smart Cards: A plastic card with a built-in microchip (e.g., a modern bank card).

• Security Tokens: A small hardware device that generates a new, temporary passcode every minute.

• Mobile SMS: A one-time code sent to your registered mobile phone via SMS to confirm a transaction.

These are often part of Two-Factor Authentication (2FA), which requires both something you know (your password) and something you have (your phone or token) to log in.

Key Takeaway for Part 4:
Encryption is the foundation of online security. The Public/Private Key system, used by SSL (HTTPS) and digital certificates, allows us to browse, shop, and bank online securely by protecting our data and verifying identity.