Cybersecurity II: Protecting Computer Systems - SSS 1 | CMPNOTE

CYBERSECURITY II: PROTECTING COMPUTER SYSTEMS

Subject: Digital Technologies

Class: SSS 1

Term: Second Term

Week: 8

Duration: 80 Minutes (Double Period)

Topic: Cybersecurity II — Protecting Computer Systems

Learning Objectives

By the end of the lesson, students should be able to:

Explain how computer systems and personal information can be protected.
Define antivirus software and state its functions.
Explain the meaning and functions of a firewall.
Describe the characteristics of strong passwords.
Identify safe computing practices.
Explain the importance of software updates, backups and responsible online behaviour.

1. Meaning of Protecting Computer Systems

Computer system protection refers to the measures used to prevent unauthorised access, damage, theft, misuse or disruption of computers, networks, programs and data.

Computer systems store important information such as school records, personal photographs, financial details, documents and passwords. If these systems are not properly protected, information may be stolen, changed, lost or exposed to unauthorised people. Protection involves using security software, strong passwords, system updates, backups and safe computing habits.

Importance of Protecting Computer Systems

Protects personal information: Prevents private information from being accessed by unauthorised people.
Prevents malware infections: Reduces the risk of harmful software damaging a computer.
Maintains data integrity: Helps prevent information from being changed or corrupted without permission.
Ensures availability: Helps keep files, applications and services accessible when needed.
Protects accounts: Reduces the risk of unauthorised access to email, social media and school accounts.
Reduces financial loss: Helps prevent fraud, theft and costs associated with recovering damaged systems.

2. Antivirus Software

Antivirus software is a security program designed to detect, block, quarantine and, where possible, remove malicious software from a computer system.

Antivirus programs help protect computers against threats such as viruses, worms, Trojans and some other forms of malware.

Functions of Antivirus Software

Scanning: Examines files, programs and selected storage locations for signs of malware.
Detection: Identifies known malware and may detect suspicious behaviour.
Quarantine: Isolates suspicious or infected files to prevent them from causing further harm.
Removal: Attempts to remove detected malware when it can do so safely.
Real-time protection: Monitors activities such as file downloads and program execution for possible threats.
Security alerts: Warns users about detected threats or unsafe activities.

Examples of Antivirus and Security Software

Microsoft Defender Antivirus.
Bitdefender.
Avast Antivirus.
ESET security products.
Norton security products.

Important: Antivirus software cannot guarantee complete protection. It should be kept updated and used together with safe browsing, careful downloading, software updates and other security measures.

Good Antivirus Practices

Keep antivirus protection enabled and updated.
Run scans when appropriate, especially if a device behaves suspiciously.
Download security software from its official source.
Do not install several security products that may conflict with one another.
Pay attention to genuine security alerts and follow safe recommended actions.

3. Firewalls

A firewall is a security system that monitors and controls network traffic entering or leaving a device or network according to defined security rules.

A firewall acts as a barrier between a trusted system or network and other networks. It helps block unwanted connections while allowing permitted communication.

Functions of a Firewall

Controls incoming and outgoing network traffic.
Blocks certain unauthorised or suspicious network connections.
Helps reduce exposure to network-based attacks.
Allows or restricts connections according to security rules.
Can help organisations enforce network access policies.

Types of Firewalls

Type	Description
Software firewall	A program or operating-system feature that filters network traffic on an individual computer or device.
Hardware or network firewall	A dedicated device or network function that controls traffic between networks, such as between an organisation's network and the Internet.

Antivirus versus firewall: Antivirus software focuses on detecting and handling malware. A firewall controls network connections and traffic. They serve different purposes and work best as parts of a wider security strategy.

4. Strong Passwords

A password is a secret combination of characters used to verify a user's identity when accessing a device, application or online account.

A strong password makes it more difficult for another person to guess or discover the secret needed to access an account.

Characteristics of a Strong Password

Length: Use a long password or passphrase. A length of at least 12–16 characters is a useful target when the service allows it.
Uniqueness: Use a different password for each important account.
Unpredictability: Avoid obvious choices such as your name, birthday, school name or simple sequences.
Variety: Where appropriate, combine letters, numbers and symbols. Length and unpredictability are more important than relying only on character variety.
Confidentiality: Never share your password with friends or strangers.

Examples of Weak and Stronger Password Choices

Weak Choice	Why It Is Weak	Better Approach
`123456`	Common and easy to guess.	Use a long, unique and unpredictable password.
`password`	A widely known word often tried by attackers.	Choose an unrelated passphrase that is difficult to predict.
`John2009`	May reveal a name and a predictable year.	Avoid personal details and use a unique password.

The examples above are for learning only. Do not use them as actual passwords.

Password Safety Rules

Never disclose your password in a message or public post.
Do not reuse the same password across different accounts.
Use a reputable password manager when available and appropriate.
Enable multi-factor authentication (MFA) where supported.
Sign out of accounts on shared computers and avoid saving passwords on public devices.
Change a password promptly if you believe it has been exposed or compromised.

5. Safe Computing Practices

Safe computing means using computers, mobile devices, applications and the Internet in ways that reduce security risks and protect information.

A. Keep Software Updated

Operating-system and application updates often fix security weaknesses. Install updates from trusted sources and enable automatic updates where appropriate.

B. Be Careful with Links and Attachments

Do not open unexpected attachments or click suspicious links. Verify unusual requests through a separate, trusted communication channel.

C. Download from Trusted Sources

Use official app stores and trusted websites. Avoid pirated software, unknown installers and programs advertised through suspicious pop-ups.

D. Use Secure Networks

Protect home and school Wi-Fi networks with strong passwords. Be cautious when using public Wi-Fi, particularly when accessing sensitive accounts. Use HTTPS websites and the security protections recommended by the service.

E. Lock Devices When Not in Use

Use a PIN, password, fingerprint or another supported screen-lock method. Lock the screen when leaving a device unattended.

F. Protect Personal Information

Avoid posting passwords, verification codes, financial information or unnecessary personal details online. Review app permissions and account privacy settings.

G. Back Up Important Files

Keep copies of important documents in a secure separate location, such as an external drive or trusted cloud storage. A backup should remain accessible if the original device is damaged or infected.

H. Use Multi-Factor Authentication

Multi-factor authentication requires an additional form of verification beyond a password, such as an authenticator-app code or security key. It provides extra protection if a password is stolen.

I. Use Standard User Accounts Where Possible

Avoid using an administrator account for ordinary tasks when a standard account is suitable. This can limit the changes that malware or an unauthorised user may make.

J. Report Security Problems

If you notice suspicious activity, a malware warning or an account you did not access, inform a trusted teacher, parent, system administrator or the appropriate support team. Do not attempt to investigate by accessing another person's account or device without permission.

6. What to Do When a Computer May Be Infected

Warning signs may include repeated unexpected pop-ups, unfamiliar programs, unusual system behaviour, security warnings or account activity you do not recognise. These signs do not always prove that malware is present, but they should be investigated carefully.

Stop entering passwords or sensitive information on a device you strongly suspect is compromised.
Follow the device's security alerts and run a scan using trusted, updated security software.
If there is an active suspected infection, disconnect the device from the network when appropriate, especially if it is spreading suspicious activity.
Ask a trusted adult, teacher, technician or system administrator for assistance.
Use a separate, trusted device to change affected passwords if necessary.
Check backups before restoring files. Do not reconnect a potentially infected device to shared networks until it has been assessed.

Safety note: Do not pay an unknown person who promises to remove malware, install unverified security tools or delete unfamiliar system files without guidance. If ransomware is suspected, seek qualified assistance before making changes.

7. Difference Between Antivirus, Firewall and Passwords

Security Measure	Main Purpose	Example
Antivirus software	Detects, blocks, quarantines or removes malware.	Scanning a downloaded file for malicious software.
Firewall	Controls incoming and outgoing network connections.	Blocking an unwanted network connection.
Strong password	Helps prevent unauthorised access to an account or device.	Using a unique passphrase for an email account.
Backup	Provides a separate copy of information for recovery.	Restoring a school document after accidental deletion.
Software update	Fixes known defects and security weaknesses.	Installing an operating-system security update.

8. Classroom Activities

Activity 1: Identify the Security Measure

Match each situation with the most suitable security measure.

A computer needs to check downloaded files for malware.
A school network needs to control unwanted connections.
A student wants to make it harder for someone to guess an email password.
A student wants to recover a project after losing the original file.

Expected answers: Antivirus software, firewall, strong unique password with MFA where available, and backup.

Activity 2: Safe or Unsafe?

Ask students to classify each action as safe or unsafe and explain why.

Installing updates from the device's official settings.
Sharing an account password with a classmate.
Opening an unexpected attachment from an unknown sender.
Keeping a backup of important schoolwork.
Using the same password for every online account.

9. Summary

Protecting computer systems involves preventing unauthorised access, damage, data loss and misuse.
Antivirus software helps detect, block, quarantine and remove malware.
A firewall monitors and controls network traffic according to security rules.
Strong passwords should be long, unique and difficult to predict.
Safe computing includes updating software, checking links, downloading from trusted sources and protecting personal information.
Backups, multi-factor authentication and responsible security reporting provide additional protection.
No single security measure can prevent every threat; several protective measures should be used together.

10. Evaluation Questions

What is meant by protecting a computer system?
Define antivirus software and state four of its functions.
What is a firewall? Mention two types of firewalls.
State five characteristics or practices associated with strong passwords.
Explain five safe computing practices.
Differentiate between antivirus software and a firewall.
State three steps a user can take when a computer is suspected of being infected.

11. Assignment

Write short notes on antivirus software and firewalls.
List eight safe computing practices and explain why each is important.
Explain how strong passwords, multi-factor authentication and backups help protect users.
Prepare a simple cybersecurity checklist that a student can use when working on a shared computer.

12. Revision Quiz

Choose the correct answer for each question, then click Check Answers to see your score.

1. What is the main purpose of antivirus software?

A. To increase screen brightness B. To create email accounts C. To detect and handle malicious software D. To improve keyboard typing speed

2. Which security measure controls incoming and outgoing network traffic?

A. Firewall B. Word processor C. Spreadsheet D. Screen saver

3. Which password practice is safest?

A. Using your birthday for every account B. Sharing your password with close friends C. Using the word "password" D. Using a long, unique and unpredictable password

4. What is one important benefit of making backups?

A. They guarantee that malware cannot enter a computer B. They help recover lost or damaged files C. They replace all security software D. They make passwords unnecessary

5. Why should software be updated regularly?

A. To remove every file from the computer B. To prevent the need for passwords C. To fix defects and known security weaknesses D. To make every website safe

6. What should you do with an unexpected attachment from an unknown sender?

A. Open it immediately B. Forward it to all classmates C. Disable antivirus protection first D. Avoid opening it and verify the message safely

7. Which statement about firewalls is correct?

A. They control network traffic according to security rules B. They automatically back up every file C. They create strong passwords for all accounts D. They replace all software updates

8. What does multi-factor authentication provide?

A. Unlimited storage space B. An additional form of identity verification C. Automatic removal of every virus D. Faster Internet speed

9. Which is a safe practice on a shared computer?

A. Save your password in the browser for everyone to use B. Leave your account open when you leave C. Sign out of your accounts when finished D. Share your verification codes

10. Which statement is true about computer security?

A. A firewall makes every other security measure unnecessary B. Antivirus software prevents every possible attack C. Strong passwords alone guarantee complete security D. Multiple security measures work together to reduce risks

CMPNOTE | Digital Technologies — SSS 1, Second Term, Week 8