hardMultiple ChoiceObjective-mapped
CRISC Practice Question: A company's control monitoring shows that a…
A company's control monitoring shows that a detective control has been 100% effective for the past year. However, a recent incident revealed that a data breach went undetected for three months. What is the MOST likely cause?
⚠ Common exam trap
Watch out — candidates often confuse 'control effectiveness' (how often it works when triggered) with 'control coverage' (whether it is designed to detect the relevant risk), leading them to incorrectly choose monitoring frequency or log tampering instead of recognizing the design gap.
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
✓
The control was not designed to detect the type of breach that occurred.
The detective control was 100% effective based on monitoring data, but it failed to detect a data breach for three months. This indicates the control was not designed to detect the specific type of breach that occurred, such as an exfiltration via an encrypted tunnel or a non-standard protocol. A control can be perfectly effective against known patterns while being blind to novel or out-of-scope attack vectors, which is why option C is correct.
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 control failure occurred but was not recorded.
Why it's wrong here
Contradicts 100% effectiveness.
- ✗
The monitoring frequency was insufficient to detect the breach.
Why it's wrong here
Breach went undetected for three months; monitoring might be periodic.
- ✓
The control was not designed to detect the type of breach that occurred.
Why this is correct
Control scope may be narrow.
- ✗
The control monitoring logs were tampered with.
Why it's wrong here
No evidence of tampering.
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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.