This CISSP practice question tests your understanding of security operations. 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.
A security analyst notices repeated failed login attempts from an internal IP address on the domain controller. After enabling account lockout, the lockouts continue but the source IP changes. What is the best next step?
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
✓
Analyze the log events to identify the attack pattern and implement additional controls such as MFA
Option A is correct because the changing source IP indicates a distributed attack, likely a password spraying or brute-force attempt from multiple compromised hosts. Analyzing log events helps identify the attack pattern (e.g., timing, targeted accounts, source IP ranges) so you can implement additional controls like MFA, which mitigates credential-based attacks regardless of source IP changes. Account lockout alone is insufficient when attackers rotate IPs, as lockout policies are per-account and per-source, not adaptive to distributed sources.
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.
✓
Analyze the log events to identify the attack pattern and implement additional controls such as MFA
Why this is correct
Understanding the attack pattern allows for targeted controls like requiring MFA for the targeted account or blocking the attack vector.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Increase the account lockout threshold
Why it's wrong here
Lockout is already enabled; attackers are using different accounts or bypassing lockout via distributed attempts.
✗
Ignore the event as it is likely a false positive
Why it's wrong here
Repeated failed logins from multiple IPs indicate a real attack, not a false positive.
✗
Disable the user account being targeted
Why it's wrong here
The target account may be legitimate; disabling it could impact business operations without stopping the attack.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume account lockout is sufficient and focus on tweaking lockout thresholds (Option B), but the changing source IP reveals a distributed attack that requires a different control like MFA, not just adjusting lockout parameters.
Detailed technical explanation
How to think about this question
In a password spraying attack, the attacker tries a few common passwords against many accounts, often from multiple IPs to evade lockout thresholds. Windows domain controllers log Event ID 4625 (failed logon) with source IP and account name; analyzing these logs can reveal patterns like a single password attempted across many accounts or a specific account targeted from many IPs. Implementing MFA (e.g., via Azure AD or on-premises AD FS) adds a second authentication factor that renders stolen credentials useless, even if the attacker bypasses lockout.
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.
TExam Day Tips
→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 security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CISSP question in full detail.
Security Operations — This question tests Security Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Analyze the log events to identify the attack pattern and implement additional controls such as MFA — Option A is correct because the changing source IP indicates a distributed attack, likely a password spraying or brute-force attempt from multiple compromised hosts. Analyzing log events helps identify the attack pattern (e.g., timing, targeted accounts, source IP ranges) so you can implement additional controls like MFA, which mitigates credential-based attacks regardless of source IP changes. Account lockout alone is insufficient when attackers rotate IPs, as lockout policies are per-account and per-source, not adaptive to distributed sources.
What should I do if I get this CISSP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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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Question Discussion
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