PEN-200 Enumeration and Reconnaissance Practice Question
When performing reconnaissance on an unknown network, you discover a service running on port 161. What is the most appropriate action to take to determine if this service can be abused?
⚠ Common exam trap
Candidates often suggest port scanning or full vulnerability scans. The most effective first step for SNMP is using specific enumeration tools like snmpwalk to test default community strings for information.
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
✓
Use snmpwalk to attempt to retrieve data using default community strings.
Port 161 is the default port for SNMP (Simple Network Management Protocol). Often, SNMP is misconfigured with default community strings like 'public' or 'private'. By testing these strings, a tester can potentially retrieve sensitive system information such as running processes, network interfaces, and even user accounts. This is a classic, high-value enumeration target that frequently yields significant information for further lateral movement or privilege escalation within the network environment.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Attempt a brute-force attack on the SSH service.
Why it's wrong here
SSH is unrelated to SNMP on port 161. Attempting to brute-force SSH when SNMP is available ignores the primary target of interest. SSH brute-forcing is also more likely to be detected by security systems, making it a poor choice compared to checking for default SNMP community strings.
- ✓
Use snmpwalk to attempt to retrieve data using default community strings.
Why this is correct
Snmpwalk is the standard tool for querying SNMP agents. Testing common default community strings is the industry-standard initial step for enumerating SNMP. If the agent responds, it reveals a wealth of information about the target's configuration, which is essential for informed decision-making during the subsequent stages of testing.
- ✗
Run a full Nmap script scan for all protocols.
Why it's wrong here
While Nmap is useful, performing a full scan for all protocols is inefficient and generates excessive network traffic. Targeted exploitation or enumeration of the specific service found is preferred in professional testing to maintain a low profile and focus efforts on the most likely vectors of compromise.
- ✗
Ignore the port as it is rarely used for anything critical.
Why it's wrong here
SNMP is a common and often overlooked vector for significant information disclosure. Ignoring it is a mistake because network administrators frequently leave it running with default settings, providing an easy entry point for intelligence gathering. Expert testers know that every open port potentially holds a critical piece of information.
About these practice questions
This PEN-200 question is part of Courseiva's 285-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official OffSec exam blueprint
This PEN-200 practice question is part of Courseiva's free OffSec 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 PEN-200 exam.