200-201 Security Monitoring Practice Question
A security analyst is reviewing firewall logs and notices a high number of denied outbound connections from an internal workstation to various external IP addresses on port 445 (SMB). What is the most likely explanation for this activity?
⚠ Common exam trap
Cisco often tests the association of specific ports with their services (e.g., SMB = 445) and expects candidates to recognize that anomalous outbound scanning on a file-sharing port indicates malware, not a benign application.
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
✓
The workstation is infected with malware attempting to spread via SMB
Port 445 is used by SMB (Server Message Block) for file sharing and network communication. A high volume of denied outbound connections from a single workstation to many external IPs on this port is a classic indicator of malware attempting to propagate via SMB vulnerabilities, such as EternalBlue (MS17-010). Legitimate SMB traffic is typically confined to internal networks, not external scanning.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The user is browsing the web and the firewall is blocking HTTP
Why it's wrong here
HTTP uses TCP ports 80 and 443, so web browsing cannot produce port 445 denials; the SMB egress pattern points to malware propagation or lateral movement attempts. Blocking HTTP would be the correct interpretation if the denied destination ports were 80 or 443 rather than 445.
- ✗
The workstation is performing a DNS lookup
Why it's wrong here
DNS lookups use UDP or TCP port 53, so queries cannot generate port 445 traffic; the denied SMB connections instead indicate worm-like scanning or SMB relay attempts. DNS resolution is the right answer when logs show repeated port 53 queries to resolver addresses, not SMB egress to many external hosts.
- ✓
The workstation is infected with malware attempting to spread via SMB
Why this is correct
SMB on port 445 is used by ransomware and worms such as WannaCry to propagate laterally. Repeated outbound attempts to many external addresses indicate the workstation scanning for reachable SMB shares, consistent with infection rather than legitimate file sharing.
- ✗
The workstation is performing a legitimate file transfer using FTP
Why it's wrong here
FTP control and data channels use TCP ports 21 and 20, so a legitimate file transfer cannot generate port 445 traffic; the denied SMB connections indicate scanning or worm activity. FTP would fit if the logs showed port 21 sessions to a known file server.
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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.