The answer is implementing a separate, write-once log storage that is inaccessible to the SIEM. This is the best preventive control because immutable logs, by design, cannot be altered or deleted once written, even by an insider with legitimate credentials or by an attacker who has compromised the SIEM itself. On the Certified Information Security Manager CISM exam, this scenario tests your understanding of defense-in-depth and the principle of least privilege applied to log management—specifically that authentication alone fails against authorized insiders, and alerting only detects tampering after the fact. A common trap is choosing stronger authentication, but the key insight is that a malicious insider often already has valid access, so you must remove the ability to delete logs entirely. Remember the mnemonic: “Write once, read many—tamper-proof logs are your security penny.”
CISM Incident Management Practice Question
This CISM practice question tests your understanding of incident management. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
An organization's incident response team uses a SIEM system to correlate logs. A malicious insider is able to cover their tracks by deleting logs from the SIEM. Which of the following is the BEST preventive control?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Implement a separate, write-once log storage that is inaccessible to the SIEM.
Option A is correct because an immutable log storage prevents tampering even if SIEM is compromised. Option B is wrong because authentication does not prevent deletions by authorized users. Option C is wrong because alerting does not prevent deletion. Option D is wrong because insiders may have authorized access.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Alert when logs are deleted from SIEM.
Why it's wrong here
Option C is wrong because alerting does not prevent deletion.
✗
Restrict SIEM access to authorized personnel only.
Why it's wrong here
Option D is wrong because insiders may have authorized access.
✗
Require multifactor authentication for SIEM access.
Why it's wrong here
Option B is wrong because authentication does not prevent deletions by authorized users.
✓
Implement a separate, write-once log storage that is inaccessible to the SIEM.
Why this is correct
Option A is correct because an immutable log storage prevents tampering even if SIEM is compromised.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the CISM exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which CISM exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Incident Management — This question tests Incident Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Implement a separate, write-once log storage that is inaccessible to the SIEM. — Option A is correct because an immutable log storage prevents tampering even if SIEM is compromised. Option B is wrong because authentication does not prevent deletions by authorized users. Option C is wrong because alerting does not prevent deletion. Option D is wrong because insiders may have authorized access.
What should I do if I get this CISM question wrong?
Identify which CISM exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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This CISM practice question is part of Courseiva's free ISACA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CISM exam.
Question Discussion
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