Network Security Exam Practice (OCR J277 Paper 1 Style)

This lesson brings together everything you have learned about network security in OCR J277 Section 1.4. We will review the key topics, practise exam-style questions, and develop effective techniques for answering security questions in the OCR GCSE Computer Science Paper 1 exam.

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Key Topics Checklist

Before the exam, make sure you can confidently explain each of the following:

Topic	Key Points to Remember
Malware types	Virus (needs host), worm (self-replicating), trojan (disguised), ransomware (encrypts files), spyware (monitors), adware (adverts)
Social engineering	Phishing (fake emails), pharming (DNS redirect), shouldering (observation), blagging (false identity)
SQL injection	Malicious SQL in input fields; prevent with input validation and parameterised queries
Penetration testing	Authorised testing; black/white/grey box; find vulnerabilities before attackers
Firewalls	Monitor and control traffic based on rules; cannot stop all threats
Proxy servers	Intermediary; hides IP, filters content, caches pages
Encryption	Symmetric (one key, fast), asymmetric (two keys, solves key distribution)
Authentication	Passwords, biometrics, 2FA; three factors: know, have, are
Network policies	AUP, password policy, backup policy, disaster recovery
Physical security	Locked rooms, CCTV, biometric access, cable locks

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How Security Questions Appear in OCR J277 Paper 1

Network security questions in OCR J277 Paper 1 typically appear as:

Short-answer questions (1-3 marks)

• "Define the term malware." (1 mark)
• "Give two examples of social engineering." (2 marks)
• "State one advantage of asymmetric over symmetric encryption." (1 mark)

Description questions (2-4 marks)

• "Describe how a phishing attack works." (3 marks)
• "Describe the purpose of penetration testing." (2 marks)
• "Explain how a firewall protects a network." (3 marks)

Extended-response questions (6-8 marks)

• "Discuss the security threats facing a company's network and recommend measures to protect against them." (8 marks)
• "A school wants to improve its network security. Evaluate the measures it could take." (6 marks)

OCR Exam Tip: For extended-response questions, structure your answer with clear paragraphs. Discuss multiple threats and multiple prevention methods. Use specific terminology (e.g. "two-factor authentication" not "extra security"). Link each threat to a specific prevention method.

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Worked Example: Short Answer

Question: State what is meant by the term 'social engineering' in the context of network security. (2 marks)

Model answer: Social engineering is the manipulation of people (1) into revealing confidential information or performing actions that compromise security (1).

Marking guidance:

• 1 mark for the idea of manipulating/deceiving people.
• 1 mark for the purpose (revealing information / gaining access / compromising security).

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Worked Example: Description

Question: Describe how SQL injection can be used to gain unauthorised access to a database. (3 marks)

Model answer: The attacker enters malicious SQL code into an input field on a website (1), such as a login form. If the input is not validated/sanitised, the SQL code is executed by the database server (1). This can allow the attacker to bypass authentication, read sensitive data, or modify/delete records (1).

Marking guidance:

• 1 mark for entering SQL code into an input field.
• 1 mark for lack of input validation allowing execution.
• 1 mark for the impact (bypass login / read data / modify data).