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1CP2-P-5.5 Robust software audit trails and code reviews

Part 5 of 6 · 1CP2-P-5 · Cyber security and robust software

The robust software worksheet, closing the loop from designing carefully to recording evidence and inspecting code.

Students will:

  • recognise behaviour that is strong evidence of robustness
  • explain how a named weakness could be exploited and how to reduce it
  • use an audit trail as evidence, and state one of its limitations
  • compare human and automated code review
  • recommend improvements from the symptoms a system shows

Inside: 8 explanation cells, 4 multiple-choice questions, 1 fill-in-the-blanks cell and 5 written answers. 20 marks, about 45 minutes.

Series: 1CP2-P-5 · Cyber security and robust software, part 5 of 6.

Shared by Coding PathwayVerified teacher

  • 18 cells
  • About 45 minutes
  • CC BY-SA 4.0
  • Shared 17 Aug 2026

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The whole resource, exactly as a class sees it. Answers and marking are held back.

Robust software, audit trails and code reviews

Robust software continues to behave correctly and predictably when faced with expected use, invalid input or foreseeable failure. Robustness protects data and service quality; it is not the same as a program merely working once with ideal input.

1. Design, record and inspect

Robust software and vulnerability identificationBuild robustly · collect evidence · inspect the coderobust behaviour• expected input works• invalid input handled• failures are controlled• recovery is predictableaudit trailrecords events such as:• user / action• date and time• success or failurecode reviewhuman or automatedinspection can find:• logic defects• vulnerabilitiesWeak authentication and missing encryption are examples of vulnerabilities—not merely untidy code.

Vulnerabilities are weaknesses that may be exploited, including weak authentication and lack of encryption. Audit trails provide evidence about events. Code reviews inspect source code or analysis results to find defects and weaknesses before or after release.

Fill in the blanks3 marks
Software that handles expected and invalid situations predictably is gap 1. A chronological event record is an gap 2. Inspection of source for defects is a gap 3.
  • audit trail
  • code review
  • encrypted
  • robust

2. Recognise robust behaviour

Robustness may involve validating input, handling errors without uncontrolled failure, preserving consistent data and producing clear outcomes. Testing supplies evidence, but passing a few tests does not prove that no vulnerability exists.

Multiple choice1 mark

Which behaviour is the strongest evidence of robustness?

  • AThe program accepts every input without checking.
  • BThe program handles valid data correctly and rejects malformed records without corrupting stored data.
  • CThe program has a colourful interface.
  • DThe program runs once on the developer's computer.
Written answer2 marks

Explain why robust software is important for a school payment system.

Link foreseeable invalid input or failure to data and service consequences.

Students type their answer here.

3. Identify vulnerabilities precisely

Weak authentication may let an attacker guess or reuse credentials. Lack of encryption may expose intercepted or stolen data. A vulnerability should be described as a weakness plus the route it creates—not just labelled 'unsafe'.

Written answer3 marks

For each weakness—short shared passwords and unencrypted stored records—explain how it could be exploited and one resulting impact.

Write two linked weakness → exploit → impact chains.

Students type their answer here.

4. Use an audit trail as evidence

An audit trail may record user/account, date and time, action, item affected and success or failure. It can reveal unusual attempts, support investigation and establish accountability. It does not prevent an event merely by recording it; logs must be protected and reviewed.

Multiple choice1 mark

Which audit event is most useful when investigating repeated failed logins?

  • AThe screen colour
  • BAccount, timestamp, attempt result and source where available
  • COnly the application name
  • DThe size of the keyboard
Written answer2 marks

Explain one benefit and one limitation of audit trails for identifying vulnerabilities or misuse.

Do not claim that recording automatically prevents an attack.

Students type their answer here.

5. Review code using people and tools

A human code review can apply context, question assumptions and notice design problems, but takes skilled time and reviewers can miss defects. An automated review can check large amounts of code consistently and quickly for known patterns, but may report false positives or miss context-dependent vulnerabilities. They can be combined.

Written answer3 marks

Compare human and automated code review, giving benefits and drawbacks.

Cover both approaches and make the comparison explicit.

Students type their answer here.

Multiple choice1 mark

An automated review flags a possible weakness. What is the best next step?

  • AAssume it is definitely exploitable and delete the system.
  • BIgnore every automated result.
  • CInvestigate the flagged code and context, then correct and retest if the weakness is confirmed.
  • DPublish the source code immediately.

6. Close the improvement loop

A useful sequence is: identify evidence → reproduce or understand the weakness → correct the design/code → test the correction → review again. Audit evidence and code review help locate problems; they do not replace implementation and verification.

Written answer3 marks

A booking system accepts malformed records and its logs show repeated failed access attempts. Recommend a robust improvement process using validation, the audit trail and code review.

Link each method to evidence or action.

Students type their answer here.

Multiple choice1 mark

Which statement is accurate?

  • AAn audit trail automatically blocks every attack.
  • BA code review guarantees vulnerability-free software.
  • CRobustness includes predictable handling of invalid input and foreseeable failures.
  • DLack of encryption affects only visual design.

Route forward

You can explain robustness and evaluate audit trails and human/automated code reviews. The principles checkpoint now consolidates malware, attack routes, controls and vulnerability identification.