GSEC Practice Question: Vulnerability Scanning and Penetration Testing
A junior security analyst at a healthcare company must scan a subnet of 254 hosts for known vulnerabilities. The analyst has no budget for commercial tools and needs a scanner that is open source, actively maintained, and capable of authenticated and unauthenticated checks. Which tool BEST meets these requirements?
⚠ Common exam trap
The trap here is assuming that any free security tool can substitute for a dedicated, feed-driven vulnerability scanner when the requirement explicitly calls for maintained authenticated and unauthenticated checks.
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
✓
OpenVAS (Greenbone Vulnerability Management)
OpenVAS, maintained as Greenbone Vulnerability Management, is the only option that is open source, actively updated, and free of per-host licensing limits. It supports both authenticated and unauthenticated scanning across large subnets, which matches the analyst's constraints. The other tools are either license-limited, not true vulnerability scanners, or designed for traffic analysis rather than vulnerability assessment.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
OpenVAS (Greenbone Vulnerability Management)
Why this is correct
OpenVAS, now delivered through Greenbone Vulnerability Management, is an open-source vulnerability scanner with a continuously updated feed and support for both authenticated and unauthenticated scans. It has no per-host licensing limit, making it suitable for scanning a 254-host subnet at no cost while still meeting the maintenance and capability requirements.
- ✗
Nessus Essentials
Why it's wrong here
Nessus Essentials is a free but license-limited version of Tenable's commercial scanner, capped at 16 IP addresses. It cannot scan a 254-host subnet without purchasing a license, so it fails the stated requirement of scanning the entire subnet with no budget. It is also not open source.
- ✗
Nmap with the NSE vuln category
Why it's wrong here
Nmap's NSE vuln scripts can detect some vulnerabilities, but Nmap is primarily a port scanner and host discovery tool. It lacks the comprehensive vulnerability database, credential-based patch auditing, and reporting depth expected from a dedicated scanner, so it does not fully satisfy the requirement for a maintained vulnerability scanner.
- ✗
Wireshark
Why it's wrong here
Wireshark is a protocol analyzer used to capture and inspect network traffic. It does not perform vulnerability scanning, does not maintain a vulnerability feed, and cannot enumerate hosts or authenticate to targets. Using it as a scanner would miss the required checks entirely, so it is not a valid choice.
Visual reference
About these practice questions
This GSEC question is part of Courseiva's 351-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 GIAC exam blueprint
This GSEC practice question is part of Courseiva's free GIAC 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 GSEC exam.