CAS-004 Security Operations Practice Question
A penetration tester is performing reconnaissance against a target. Which TWO of the following are examples of active reconnaissance? (Select TWO.)
⚠ Common exam trap
The trap is confusing passive OSINT techniques (WHOIS, social media) with active probing; candidates may incorrectly select D or E as active.
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
✓
Banner grabbing
Banner grabbing (A) is active reconnaissance because the tester directly connects to target services (e.g., via netcat or telnet to a port) and reads the service's response banner, which generates traffic and can be logged by the target. Port scanning (C) is also active reconnaissance since tools like Nmap send TCP SYN, TCP connect, or UDP probes directly to the target's IP addresses to discover open ports, again interacting with the target's systems. In contrast, social media profiling (B), WHOIS lookup (D), and searching job postings (E) are passive reconnaissance techniques that rely on publicly available third-party information without directly touching the target's infrastructure, so they do not qualify as active reconnaissance.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Banner grabbing
Why this is correct
Banner grabbing sends crafted requests directly to target services and reads their responses, so the tester's traffic reaches the target's systems. That interaction with the target distinguishes active reconnaissance from passive methods such as OSINT or DNS lookups, which never touch the target directly.
- ✗
Social media profiling
Why it's wrong here
Social media profiling draws on third-party public content, generating no traffic to the target's infrastructure — passive reconnaissance. It is tempting because employee posts expose technologies, roles, and email formats, but the target's own systems neither receive nor log the activity.
- ✓
Port scanning
Why this is correct
Port scanning transmits probe packets to target hosts and analyses the replies to determine open ports and services. Because packets are sent to and processed by the target, it constitutes active reconnaissance, unlike passive techniques that gather information from third-party sources without contacting the target.
- ✗
WHOIS lookup
Why it's wrong here
WHOIS queries public registry databases, so no packets reach the target's own systems — that is passive reconnaissance. It is tempting because WHOIS reveals registrant, nameserver, and contact data useful for mapping an estate, but the target never observes the query.
- ✗
Searching job postings for technology details
Why it's wrong here
Job postings sit on third-party sites, so reviewing them sends no traffic to the target — passive reconnaissance. It is tempting because adverts leak stack details such as cloud providers and versions, yet the target observes nothing, unlike direct scanning or DNS interrogation.
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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 CompTIA exam blueprint
This CAS-005 practice question is part of Courseiva's free CompTIA 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 CAS-005 exam.