Design security operations, identity, and compliance capabilities →easyMultiple ChoiceObjective-mapped
SC-100 Practice Question: Design security operations, identity, and compliance capabilities
Your organization uses Microsoft Sentinel and has enabled User and Entity Behavior Analytics (UEBA). The security team receives an alert for a user who has failed authentication 10 times in 5 minutes. What should you configure to reduce false positives while ensuring legitimate brute-force attacks are still detected?
⚠ Common exam trap
Many candidates assume modifying the analytics rule (Option C) is the correct tuning mechanism, but UEBA-specific thresholds are configured separately from the underlying analytics rule, and adjusting the rule itself would affect all users and all detection logic, not just the behavioral anomaly component.
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
✓
Customize the anomaly threshold in UEBA
Customizing the anomaly threshold in UEBA allows you to adjust the sensitivity of the behavioral baseline, reducing false positives for users who legitimately fail authentication multiple times while still detecting true brute-force attacks. UEBA learns normal behavior patterns and flags deviations; by raising the threshold, you require a higher deviation from the baseline before an alert fires, preserving detection of actual attacks.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Customize the anomaly threshold in UEBA
Why this is correct
Customizing the anomaly threshold in UEBA is the correct approach because UEBA uses machine learning models that assign anomaly scores to user behaviors, and these models expose threshold and sensitivity settings you can tune. By adjusting the sensitivity, you directly influence the score required to trigger an alert, effectively filtering out low-confidence anomalies that cause false positives while still detecting genuinely suspicious activity. This is the intended, documented method for reducing noise from UEBA-detected behaviors without sacrificing the underlying behavioral analytics capability.
- ✗
Disable UEBA for that user
Why it's wrong here
Disabling UEBA for that user completely removes behavioral analytics and anomaly detection for their account, so no anomalies will be generated at all—neither false positives nor legitimate detections. This is a heavy-handed administrative action that strips the user of security monitoring, increasing the risk that real malicious behavior goes unnoticed. It does not tune detection; it eliminates it, and it also breaks Sentinel's ability to build a behavioral baseline for that user, which is why it is not a valid way to reduce false positives while preserving detection.
- ✗
Modify the analytics rule that triggered the alert
Why it's wrong here
The alert was generated by UEBA's anomaly detection engine, not by a scheduled or near-real-time analytics rule that you could independently modify in Sentinel. Analytics rules are separate constructs that produce incidents from KQL queries, whereas UEBA anomalies are evaluated by a different pipeline with its own model parameters and thresholds. Editing an unrelated analytics rule would have no effect on the UEBA alert, so this option mistakes the source of the detection and would leave the false-positive issue completely unresolved.
- ✗
Create a playbook to auto-acknowledge the alert
Why it's wrong here
Creating a playbook to auto-acknowledge the alert is merely an automation workaround that hides the false positive from the queue without addressing the root cause. Playbooks are designed to respond to incidents with actions like enrichment, notification, or remediation—they have no control over the UEBA detection threshold or the anomaly score calculation. Auto-acknowledging would only suppress the alert's visibility, which risks missing a future genuine anomaly that generates a similar alert and also leaves the underlying false positive recurring continuously.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SC-100 practice question is part of Courseiva's free Microsoft 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 SC-100 exam.