← IGCSE Computer Science Paper 1

Choosing a solution to counter a threat

A solution chosen to stop a specific threat, such as a firewall for hacking, SSL for interception or anti-malware for malware, plus an explanation of how it works.

Part of: IGCSE Computer Science 0478 — 5.3 Cyber Security — Module 49, ACARA Digital Technologies Years 7–8 — Networks and Cyber Threats — Module 72, ACARA Digital Technologies Years 9–10 — Networked Systems and Access Control — Module 146, ACARA Digital Technologies Years 9–10 — Cyber Security Threats and Vulnerabilities — Module 88, WA Computer Science ATAR Year 11 — Network Communications — Module 136, WA Computer Science ATAR Year 11 — Cyber Security — Module 138

Understanding Choosing a solution to counter a threat in IGCSE Computer Science Paper 1

What it does: Encryption scrambles data so an interceptor only sees meaningless text, which is why it counters interception. Pharming and phishing rely on fake sites or messages, so checking the URL and the message for warning signs stops the user being fooled. Brute-force attacks guess passwords. A long, varied password takes far longer to guess, and two-step verification stops a guessed password from being enough to log in. Anti-malware scans files and compares them with known malware. Updates make sure that new malware can be spotted. A firewall examines incoming traffic against rules and blocks suspicious requests. A proxy server can also filter traffic and shield the real web server.

Common mistakes: Anti-malware does not stop someone guessing passwords. A brute-force attack is countered with a strong password (plus two-step verification), so line 2 should assign "strong password". Two-step verification needs BOTH the password and the code. Using OR lets an attacker in with just a guessed password, so it should be AND.

Class: _____________________  ·  Name: _____________________  ·  Date: _________

Free printable worksheet with full answer key — or add this module to a class and your students practise it interactively.

🖨 Print worksheet + answer key Add Choosing a solution to counter a threat to a class →

This module's key terms are also in a printable crossword (Modules 553–577) and word search (Modules 553–607).

Take this worksheet further — free with Cloodit

Each concept is reinforced from every angle — learned, then applied, then tested.

Learning
Duo
A hacker keeps guessing a user's password with software that tries thousands of combinations. Which solution best counters this?
A strong password plus two-step verificationAnti-spyware software
Matches
threat: malware -> solution: firewall only
↓
A firewall only filters network traffic, so it cannot remove malware already on the computer. Anti-malware software and updates are needed.
Applying
Meanings
Term
countermeasure
Meaning
A solution chosen to stop a specific threat, such as a firewall for hacking, SSL for interception or anti-malware for malware, plus an explanation of how it works.
Practice
threat ← "DDoS"
Testing
Gaps
solution = ""
Check Answer
Spots
1threat ← "brute-force attack"
2solution ← "anti-malware"

Cloodit turns curriculum-aligned coding content into journeys students work through one biome at a time.

The 'Jellyfish' badge — Flow Controller, one of Cloodit's 106 collectible badges
Students earn collectable badges

Over 100 of them, across seven natural biomes.

Study Buddy
Students build a real study resource

Turns their work into revision material ready for Flash Cards and Exam study.

Diamond Dash — one of Cloodit's live, competitive Sprint games
Students lock in with Sprints

Live, competitive practice for the start of the lesson or a teacher-led lesson finisher.

A Cloodit certificate of achievement, ready to personalise and print
Custom printable certificates

Honour your top performers, or encourage a student who's trying hard — ready to print in seconds.

Add to class →

Quick Questions

1. A hacker keeps guessing a user's password with software that tries thousands of combinations. Which solution best counters this?
A. Anti-spyware software
B. A strong password plus two-step verification ✓
Brute-force attacks guess passwords. A long, varied password takes far longer to guess, and two-step verification stops a guessed password from being enough to log in.
2. A student's computer has been infected by a virus hidden in a downloaded file. Which solution counters this threat?
A. Anti-malware software that scans and removes it, kept up to date ✓
B. A proxy server that hides the school IP address
Anti-malware scans files and compares them with known malware. Updates make sure that new malware can be spotted.
3. An email says 'Your bank account is locked, click this link now.' The link address looks slightly odd. What is the best countermeasure?
A. Check the URL and the message for warning signs before clicking ✓
B. Use a firewall to encrypt the email
Phishing relies on the user being tricked. Checking the URL and the wording of the message (spelling errors, urgency, unknown sender) stops the user from visiting the fake site.
4. Customer card details are being read by someone while they travel across a network to a shop's website. Which solution stops this interception?
A. A strong password on the shop's staff accounts
B. SSL or encryption, so intercepted data cannot be understood ✓
Encryption scrambles the data into ciphertext. An interceptor can capture it but cannot read it without the decryption key.
5. A website is flooded with thousands of requests from many computers so real users cannot get in (a DDoS attack). Which solution helps?
A. A firewall or proxy server that filters and blocks the traffic ✓
B. Two-step verification for the web server's users
A firewall examines incoming traffic against rules and blocks suspicious requests. A proxy server can also filter traffic and shield the real web server.

Match the Pairs

countermeasure → A solution chosen to stop a specific threat, such as a firewall for hacking or SSL for interception
threat: brute-force -> strong password + 2-step verification → A long, varied password makes guessing take too long, and a second check stops a guessed password from being enough
Intercepted data on a network is made unreadable to anyone who captures it, so the matching solution is encryption such as SSL → threat: interception -> solution: SSL / encryption
A fake website that copies a real one is spotted by checking the URL carefully before entering any details → threat: pharming -> solution: check the URL
threat: malware -> solution: firewall only → A firewall only filters network traffic, so it cannot remove malware already on the computer. Anti-malware software and updates are needed.
threat: DDoS attack -> solution: strong password → A strong password does not stop a flood of traffic. A firewall or proxy server should be used to filter the traffic.

Key Term

countermeasure
A solution chosen to stop a specific threat, such as a firewall for hacking, SSL for interception or anti-malware for malware, plus an explanation of how it works.

Fill in the Blanks

1. threat = "brute-force" solution = "strong password"
Hint: Type a solution that makes guessing every combination take far too long.
2. threat = "malware" solution = "anti-malware" updates = "keep software up to date"
Hint: Type the type of software that scans for and removes harmful programs.
3. threat = "interception" solution = "SSL encryption"
Hint: Type the threat where data is captured on a network and which SSL scrambles to stop.
4. threat = "phishing" solution = "check the URL of links"
Hint: Type the web address term a student should inspect to spot a fake site.
5. threat = "DDoS" solution = "firewall"
Hint: Type the security tool that monitors and blocks suspicious incoming traffic.

Spot the Error

Question 1
A threat ← "brute-force attack"
B solution ← "anti-malware"
C extra ← "2-step verification"
D OUTPUT solution
Line B — Anti-malware does not stop someone guessing passwords. A brute-force attack is countered with a strong password (plus two-step verification), so line 2 should assign "strong password".
Question 2
A threat ← "brute-force"
B IF password_ok OR code_ok THEN
C LOGIN user
D ENDIF
Line B — Two-step verification needs BOTH the password and the code. Using OR lets an attacker in with just a guessed password, so it should be AND.
Question 3
A threat ← "interception"
B solution ← "message check"
C IF sender ≠ known THEN
D OUTPUT "Do not reply"
E ENDIF
Line A — The solution is a message check, which counters phishing, not interception. Line 1 should name the threat as "phishing".
Question 4
A IF threat = "DDoS" THEN
B solution ← "encryption"
C ENDIF
D OUTPUT solution
Line B — Encryption does not stop a flood of traffic. A DDoS attack is countered with a firewall (or proxy server) that blocks the unwanted traffic, so line 2 should be "firewall".
Question 5
A threat ← "phishing"
B solution ← "URL check"
C domain ← "b4nk.xyz"
D IF domain = "bank.com" THEN
E OUTPUT "Do not click"
F ENDIF
Line D — The check is reversed. The warning should show when the domain is NOT the real one, so the condition should use ≠ instead of =.

Student with a class code? Join your class →