CEH Footprinting, Reconnaissance and Scanning Practice Question
Which of the following is the PRIMARY purpose of banner grabbing during the reconnaissance phase?
⚠ Common exam trap
A common mix-up: candidates confuse banner grabbing with OS fingerprinting or port scanning, but the CEH exam specifically tests that banner grabbing's primary goal is service version identification, not OS detection or port discovery.
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
✓
To determine the version of a running service
Banner grabbing is a technique used to extract service banners that often include software name and version details. The primary purpose is to determine the version of a running service, as this information allows an attacker to identify known vulnerabilities specific to that version for further exploitation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
To determine the version of a running service
Why this is correct
Banner grabbing involves connecting to a network service (e.g., HTTP, FTP, SSH) and observing the initial data or "banner" it sends back. This banner frequently contains crucial information such as the service name, its specific version number, and sometimes even the underlying operating system or patch level. Identifying these versions is critical for penetration testers to pinpoint known vulnerabilities associated with particular software releases, enabling targeted exploit attempts.
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To discover open ports
Why it's wrong here
Discovering open ports is primarily achieved through port scanning techniques, such as TCP SYN scans or UDP scans, which systematically probe a range of ports on a target system to identify active listeners. Banner grabbing, conversely, is a subsequent step performed after an open port has been identified. Its purpose is not to find the port itself, but to extract information from the service listening on that already-discovered open port.
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To identify the operating system
Why it's wrong here
While some service banners might incidentally include operating system information (e.g., "Apache/2.4.6 (CentOS)"), the primary and most reliable method for identifying an operating system is through active or passive OS fingerprinting. Techniques like analyzing TCP/IP stack characteristics (e.g., initial TTL values, window sizes, flag combinations) or examining specific network protocols provide a much more accurate and consistent determination of the underlying OS than relying solely on often-incomplete or misleading banner data.
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To map the network topology
Why it's wrong here
Mapping network topology involves a comprehensive set of techniques to understand the layout, interconnections, and devices within a network. This typically includes tools like traceroute or tracert to identify hops, ICMP scans to discover hosts, SNMP queries to gather device information, and even physical inspection. Banner grabbing provides information about specific services on individual hosts, but it offers no direct insight into the overall network structure, routing paths, or the relationships between different network segments.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CEH practice question is part of Courseiva's free EC-Council 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 CEH exam.