200-201 Security Monitoring Practice Question
An analyst receives an IDS alert with signature name 'ET TROJAN Win32.Zeus Checkin' and severity 'high'. The alert shows source IP 192.168.1.50 and destination IP 198.51.100.20 on port 443. Which action should the analyst take FIRST?
⚠ Common exam trap
Cisco often tests the principle that containment (isolating the host) takes precedence over blocking external IPs or performing forensic analysis, and that encryption does not invalidate IDS alerts because signatures can detect malicious patterns in metadata or handshake characteristics.
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
✓
Isolate the source host from the network to prevent further communication.
The alert indicates a high-severity Zeus Trojan check-in, which is a known malware communicating with a command-and-control (C2) server. The first priority is to contain the threat by isolating the source host (192.168.1.50) to prevent further data exfiltration or lateral movement. Even though the traffic is encrypted over port 443 (HTTPS), the signature confirms malicious activity, so immediate isolation is the correct initial response per incident response best practices.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Isolate the source host from the network to prevent further communication.
Why this is correct
Isolating the host stops the malicious activity and prevents lateral movement.
- ✗
Check the host's web browsing history for suspicious websites.
Why it's wrong here
This action is less immediate and can be done after containment.
- ✗
Immediately block the destination IP on the firewall.
Why it's wrong here
Blocking the destination IP may disrupt the attack but does not address the compromised host. Isolation is more urgent.
- ✗
Ignore the alert because the traffic is encrypted over port 443.
Why it's wrong here
Encryption does not mean the traffic is safe; Zeus can use HTTPS for command and control.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-201 practice question is part of Courseiva's free Cisco 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 200-201 exam.