Apply anti-malware, updates and firewalls
Explain how prevention and network controls reduce, detect or contain different security threats.
Section 5 · The internet and its uses
Exam scope and assessment notes
This sequence follows Cambridge IGCSE Computer Science 0984, 2026–2028 syllabus Version 4. It covers subject content sections 5.1–5.3 only. The separately published 2029–2031 syllabus is not mapped here. Practice is original, self-checked and does not award an official Cambridge grade. Full timed papers and human subject-teacher review remain outstanding. Cambridge states that 0984 has the same 2026–2028 subject content as 0478, with 9–1 grading. In June and November, Cambridge lists 0984 in Administrative zone 3 and for centres in Oman and the UAE. Confirm availability for your centre and exam series with Cambridge International. The separately published 2029–2031 syllabus changes to Python 3 only and removes pseudocode; this 2026–2028 route does not cover those changes.
Before you begin
- No programming language is required. Be comfortable with place value and multiplication; each lesson introduces the computer-science notation it uses.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Why install security updates promptly?
What you will learn
- Describe anti-malware and automated updates
- Explain firewall filtering
- Explain the use and limits of proxy servers
Security uses layered controls
Anti-malware, including anti-virus and anti-spyware, scans for or blocks malicious software. Regular automated updates patch known weaknesses in operating systems and applications; delaying updates leaves some known routes open.
Apply and check the rule
A firewall filters network traffic according to rules, blocking connections that should not reach a device or network. A proxy server makes requests on behalf of users and can apply filtering or logging. No single control blocks every threat, so use layered protection, backups and sensible access rules.
Pause and explain
Which control scans for malicious software?
Worked example
A school wants to reduce malware risk and block unauthorised incoming connections. Name a suitable control for each.
Show the worked solution
- Anti-malware can detect or block malicious software.
- A firewall filters network connections against configured rules.
- Updates patch known vulnerabilities.
Answer Use anti-malware for malicious software, a firewall for network traffic, and regular updates to close known weaknesses.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Match automatic updates, anti-malware and firewall to patching, malicious-code detection and traffic filtering.
Give me a hint
Separate software content from network connections.
Compare my reasoning
- Updates patch known weaknesses.
- Anti-malware detects or blocks malicious code.
- A firewall filters network traffic using rules.
Updates patch; anti-malware scans software; a firewall filters connections.
Look for these in your work
- Three controls
- Three functions matched
A user installs anti-malware but never updates the operating system. Explain one remaining risk.
Give me a hint
Consider weaknesses in the system that the scanner cannot repair.
Compare my reasoning
- The system may contain known unpatched vulnerabilities.
- An attacker may exploit a weakness without relying on a file the scanner detects.
- Automated updates reduce this exposure.
Unpatched weaknesses may still be exploited. Keep the operating system and applications updated as well as using anti-malware.
Look for these in your work
- Unpatched risk
- Possible exploit
- Complementary control
A school proxy blocks some harmful sites, but a new phishing page is not yet on its filter list. Explain why the proxy is not a complete defence and add two controls.
Give me a hint
Combine technical filtering with updated controls and user verification.
Compare my reasoning
- A proxy can filter or log requests but may miss new or changed sites.
- Anti-malware and updates reduce different software risks.
- Users should inspect links and verify unexpected requests through a trusted channel.
A proxy is only one layer and may not know every new site. Keep software updated, use anti-malware, and teach users to verify unexpected links or requests.
Look for these in your work
- Proxy limit
- Two additional layers
- User behaviour
Common mistakes
- Calling a firewall a virus scanner
- Assuming an update eliminates every future vulnerability
What can you explain now?
What does a firewall primarily filter?
Compare with the explanation
Network traffic according to security rules
It controls which connections are allowed or blocked.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
What different jobs do anti-malware, updates, firewalls and proxies perform?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.