The correct answer is to implement an account lockout after a threshold of failed attempts. This security control directly mitigates brute force attacks by rate-limiting authentication attempts at the application layer, preventing an attacker from continuously guessing passwords across multiple user accounts from a single IP address. On the ISC2 Certified in Cybersecurity CC exam, this scenario tests your understanding of access control mechanisms and the principle of defense against credential-based attacks. A common trap is choosing IP blocking instead, but account lockout is the more precise control because it stops the password guessing process itself, regardless of the source address. For the exam, remember that brute force mitigation relies on throttling the number of tries, not just the origin of the traffic. A useful memory tip is “Lock the account, not just the IP” to recall that account lockout targets the authentication attempt count directly.
ISC2 CC Security Operations Practice Question
This CC practice question tests your understanding of security operations. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 a single IP address targeting multiple user accounts. Which security control should be implemented to mitigate this attack?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Implement account lockout after a threshold of failed attempts.
Option A is correct because implementing an account lockout policy after a defined threshold of failed attempts (e.g., 5 failed attempts within 15 minutes) directly mitigates brute-force password guessing attacks from a single source. This control prevents an attacker from continuously trying different passwords across multiple accounts, effectively rate-limiting the attack at the authentication layer.
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.
✓
Implement account lockout after a threshold of failed attempts.
Why this is correct
Mitigates brute-force attacks by locking accounts after multiple failures.
Related concept
Read the scenario before looking for a memorised answer.
✗
Enable single sign-on (SSO).
Why it's wrong here
Does not address failed login attempts; SSO centralizes authentication but doesn't prevent brute force.
✗
Require complex passwords.
Why it's wrong here
Helps against password guessing but not automated brute force from a single IP.
✗
Disable the accounts after one failed attempt.
Why it's wrong here
Too restrictive; would cause denial of service for legitimate users.
Common exam traps
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the distinction between preventive controls (like account lockout) and deterrent controls (like complex passwords), and the trap here is that candidates choose complex passwords because they think stronger passwords stop brute-force attacks, but they fail to recognize that unlimited attempts still allow eventual guessing regardless of password complexity.
Detailed technical explanation
How to think about this question
Account lockout policies are typically configured in Active Directory via Group Policy (e.g., 'Account lockout threshold' set to 5 invalid logon attempts) and in Linux via pam_tally2 or faillock. The lockout duration (e.g., 30 minutes) and reset counter (e.g., after 15 minutes) are critical to prevent permanent lockout of legitimate users while still thwarting brute-force attacks. In real-world scenarios, attackers may use distributed IPs to bypass IP-based blocking, making account lockout essential as a per-user control.
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 CC 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: Implement account lockout after a threshold of failed attempts. — Option A is correct because implementing an account lockout policy after a defined threshold of failed attempts (e.g., 5 failed attempts within 15 minutes) directly mitigates brute-force password guessing attacks from a single source. This control prevents an attacker from continuously trying different passwords across multiple accounts, effectively rate-limiting the attack at the authentication layer.
What should I do if I get this CC question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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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