200-201 Security Monitoring Practice Question
A SOC analyst is reviewing a NetFlow record and sees that a single internal IP has communicated with multiple external IPs on port 445 (SMB) within a short time frame. Which type of activity is most likely indicated?
⚠ Common exam trap
Cisco often tests the distinction between normal traffic patterns and malicious scanning by using a single internal IP connecting to many external IPs on a specific port, where candidates may mistakenly associate SMB only with legitimate file sharing (Option A) rather than recognizing the scanning behavior.
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
✓
SMB scanning or worm propagation
Port 445 is used by SMB for file sharing, but a single internal IP communicating with many external IPs in a short time frame is characteristic of scanning or worm propagation. Worms like EternalBlue exploit SMB vulnerabilities to spread rapidly, generating many outbound connections to random or sequential external IPs on port 445. This pattern is not typical of normal file sharing, which involves sustained connections to known servers.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Normal file sharing activity
Why it's wrong here
Normal SMB file sharing stays within the internal network between known hosts, not one internal address contacting numerous external addresses on port 445 in a short window. That fan-out pattern indicates scanning or worm propagation. Normal sharing would show repeated sessions with a small set of internal peers.
- ✗
Data exfiltration over SMB
Why it's wrong here
Exfiltration implies bulk data leaving the network to one destination, whereas this record shows one internal host fanning out to many external addresses on port 445, the signature of SMB scanning or worm propagation. Exfiltration would fit sustained high-volume transfers to a single external endpoint.
- ✓
SMB scanning or worm propagation
Why this is correct
One internal host contacting many external addresses on port 445 indicates SMB scanning or worm propagation seeking vulnerable shares. The fan-out pattern and SMB port distinguish it from normal file sharing, satisfying the stem's NetFlow scenario.
- ✗
DNS tunneling
Why it's wrong here
DNS tunneling uses port 53, not 445.
About these practice questions
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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.