CAS-004 Security Operations Practice Question
A SOC analyst is tuning a SIEM correlation rule to detect lateral movement. The rule currently triggers on a single failed authentication followed by a successful authentication from a new IP address within 5 minutes. Which improvement would best reduce false positives while maintaining detection of pass-the-hash 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
✓
Require two failed authentications before the success
Pass-the-hash attacks often involve a single failed authentication (due to incorrect hash) followed by a success. However, requiring two failures before the success would reduce false positives from accidental typos while still catching many pass-the-hash attempts. Adding source IP whitelisting can also cut false positives from admins.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Require two failed authentications before the success
Why this is correct
Two failures reduce the chance of accidental typos, and pass-the-hash often has multiple failures before success.
- ✗
Increase the time window to 30 minutes
Why it's wrong here
A longer window may include more benign activity and increase false positives.
- ✗
Add a condition that the source IP is not in the company's IP range
Why it's wrong here
Lateral movement often originates from internal IPs, so excluding internal IPs would miss attacks.
- ✗
Remove the failed authentication requirement and only trigger on successful authentication from a new IP
Why it's wrong here
This would cause many false positives from legitimate remote access.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CAS-005 practice question is part of Courseiva's free CompTIA 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 CAS-005 exam.