easyMultiple ChoiceObjective-mapped
CAS-004 Practice Question: A security analyst receives an alert indicating…
A security analyst receives an alert indicating an internal host is sending outbound traffic on TCP port 25 to multiple external IP addresses. Which action should the analyst take first to investigate potential data exfiltration?
⚠ Common exam trap
The trap here is that candidates often jump to containment (blocking traffic) or remediation (antivirus scan) without first verifying the host's authorized role, which CompTIA tests to ensure you follow a structured incident response process (identify before contain).
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
✓
Check if the host is configured as a mail server in the organization's asset database.
The first step in investigating potential data exfiltration over TCP port 25 (SMTP) is to verify whether the host is authorized to send email. If the host is a legitimate mail server, the traffic may be normal; if not, it could indicate malware or a misconfigured application exfiltrating data via SMTP. This aligns with the CAS-004 objective of validating asset roles before escalating to containment.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Submit a change request to implement an email content filter.
Why it's wrong here
This is a long-term control, not an immediate investigation step.
- ✓
Check if the host is configured as a mail server in the organization's asset database.
Why this is correct
This step quickly confirms if the traffic is expected, avoiding unnecessary escalation.
- ✗
Block the outbound traffic on the firewall to prevent potential data exfiltration.
Why it's wrong here
Blocking first may cause service disruption without proper investigation.
- ✗
Run a full antivirus scan on the host to detect any malware.
Why it's wrong here
This is a later step; initial verification of the host's role is faster and less disruptive.
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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.