easyMultiple Choice
CRISC Practice Question: Has a risk indicator that shows the number of…
An organization has a risk indicator that shows the number of failed login attempts per day. The threshold is 100. Last week, the number spiked to 200 on two days. What does this indicate?
⚠ Common exam trap
Watch out — candidates often confuse a spike in failed logins with a DoS attack, but DoS attacks target availability (e.g., SYN flood) rather than authentication failures, which are a confidentiality/integrity concern.
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
✓
There may be a brute-force attack in progress.
A spike in failed login attempts from a baseline of 100 to 200 per day is a classic indicator of a brute-force attack, where an attacker systematically tries multiple username/password combinations. This risk indicator directly measures authentication failures, which are the primary symptom of such an attack. The threshold breach signals that the control (account lockout or rate limiting) may be insufficient or failing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The system is experiencing a denial-of-service attack.
Why it's wrong here
A spike in failed logins alone does not establish a denial-of-service attack, which requires evidence of resource exhaustion or traffic flooding rather than authentication failures. It is tempting because volumetric attacks can raise error counts, but a DoS would be the answer if the indicator tracked connection or bandwidth saturation.
- ✓
There may be a brute-force attack in progress.
Why this is correct
Doubling the failed-login threshold on two separate days signals sustained credential-guessing activity against accounts. Such repeated authentication failures concentrated in time are characteristic of a brute-force attack rather than routine user error or isolated lockouts.
- ✗
The password policy needs to be updated.
Why it's wrong here
A password policy change would alter failure patterns persistently after deployment, not cause an isolated two-day spike. It is tempting because weak policy drives failed attempts, but policy revision is the answer when the indicator shows sustained failures tied to complexity or expiry rules rather than a brief threshold breach.
- ✗
Users have forgotten their passwords.
Why it's wrong here
Forgotten passwords would produce a gradual, steady rise across many accounts, not a two-day doubling of the daily aggregate. It is tempting because authentication failures do stem from user error, but this option is correct only when the indicator is scoped per-user and correlates with helpdesk reset volumes.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CRISC 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 CRISC exam.