PT0-002 Reconnaissance and Enumeration Practice Question
A penetration tester is conducting passive reconnaissance on a target organization. The tester wants to discover subdomains and associated email addresses without directly interacting with the target's infrastructure. Which combination of tools and sources would be most effective for this task?
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
✓
theHarvester with Shodan and Google dorks
theHarvester is an OSINT tool that can gather emails, subdomains, and other data from public sources like search engines, PGP key servers, and the Shodan database. It performs passive collection. Maltego can also be used but requires more setup. Shodan and Google dorks are specific searches but theHarvester automates multiple sources.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Wireshark capturing network traffic
Why it's wrong here
Wireshark is a packet-capture utility that requires placement on a network segment where target traffic traverses, often inside the target's environment or via a tap. Although capturing packets does not transmit data, it is not passive OSINT because it depends on direct network access and does not leverage publicly available intelligence sources. Passive reconnaissance should only use external, open-source information without any direct interaction.
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Nikto scanning the web server
Why it's wrong here
Nikto is an active web vulnerability scanner that sends dozens of crafted HTTP requests to a web server to identify misconfigurations and vulnerable files. Every request is a direct interaction with the target, causing server logs entries and potentially triggering intrusion detection or web application firewalls. This active probing contradicts the goal of remaining undetected during passive reconnaissance.
- ✓
theHarvester with Shodan and Google dorks
Why this is correct
theHarvester is an OSINT tool that passively aggregates data by querying public APIs and search engines such as Shodan and Google dorks. It searches publicly indexed emails, subdomains, and hostnames without ever sending packets directly to the target's own systems, preserving anonymity and leaving no traces in target logs. This makes it a legitimate passive reconnaissance technique.
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Nmap with subdomain bruteforce
Why it's wrong here
Nmap is an active scanner that sends crafted packets directly to target hosts, and its subdomain brute-force mode relies on generating high volumes of DNS queries that hit target infrastructure or its resolvers. This creates observable traffic and logs, violating the strict no-touch rule of passive reconnaissance. Passive OSINT must never initiate any connection to the target's systems.
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Related to this question
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Shodan and Censys for Asset Discovery
Key term
theHarvester
theHarvester is an open-source intelligence (OSINT) tool used to gather emails, subdomains, IP addresses, and other public data about a target from search engines and public sources.
Key term
Maltego
Maltego is a graphical open-source intelligence tool used for information gathering and reconnaissance, enabling users to map and visualize relationships between entities like people, domains, and networks.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PT0-003 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 PT0-003 exam.