ISC2 CC Access Controls Concepts Practice Question
A system administrator is configuring account lockout policies to mitigate brute-force attacks. Which TWO settings are most critical for this purpose?
⚠ Common exam trap
The trap is selecting password policy settings (length, history, expiration) as critical for lockout, when the question specifically asks about lockout policies to mitigate brute-force attacks.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Account lockout threshold (e.g., 5 failed attempts)
Option B, the account lockout threshold (e.g., 5 failed attempts), is correct because it directly limits how many incorrect password guesses an attacker can make before the account is disabled, which is the core mechanism that stops brute-force attempts. Option C, lockout duration (e.g., 30 minutes) or administrator unlock, is correct because it determines how long the account stays locked; without a duration or manual unlock requirement, the lockout either never ends or can be trivially bypassed, so it works together with the threshold to make brute-forcing impractical. The unmarked options do not belong because A (90-day password changes), D (password history of 10), and E (minimum length of 8) are password policy settings that improve password strength and prevent reuse, but they do not detect or block repeated failed authentication attempts, which is what account lockout specifically addresses.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Requiring password changes every 90 days
Why it's wrong here
Password expiry limits how long a compromised credential stays valid, but it neither counts failed attempts nor locks the account, so an attacker can keep guessing indefinitely. It belongs in a broader password policy, not in the lockout threshold and duration settings that actually stop brute-force attempts.
- ✓
Account lockout threshold (e.g., 5 failed attempts)
Why this is correct
The lockout threshold defines how many consecutive failed authentication attempts trigger the lockout, directly throttling brute-force guessing. Setting it low, such as five, limits an attacker's attempts per account before the account is disabled, satisfying the requirement to mitigate brute-force attacks.
- ✓
Lockout duration (e.g., 30 minutes) or administrator unlock
Why this is correct
Lockout duration determines how long the account stays disabled after the threshold is exceeded, or requires administrator unlock. This slows sustained brute-force campaigns by forcing attackers to wait between attempt batches, satisfying the mitigation requirement alongside the threshold setting.
- ✗
Password history of 10 remembered passwords
Why it's wrong here
Password history prevents users from cycling back to previous passwords, which addresses credential reuse rather than brute-force guessing. Lockout effectiveness depends on the failed-attempt threshold and lockout duration, which halt repeated authentication attempts against an account.
- ✗
Password minimum length of 8 characters
Why it's wrong here
Minimum length strengthens resistance to guessing but imposes no counter or lockout, so unlimited attempts remain possible. The critical lockout settings are the failed-attempt threshold and the lockout duration, which stop the attack after a set number of failures.
Go deeper
Related to this question
Learn chapter
Authentication and Authorization Methods
Key term
Authentication
Authentication is the process of verifying that someone or something is who or what it claims to be before granting access to a system or resource.
Key term
Password policy
A set of rules designed to enhance computer security by encouraging users to create strong, secure passwords and store them properly.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official ISC2 exam blueprint
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