CEH Practice Question: Advanced Topics: Wireless, Cloud, IoT, Cryptography
A security analyst captures a large number of initialization vectors (IVs) on a WEP-protected network. Which tool is most commonly used to crack the WEP key using IVs?
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
✓
Aircrack-ng
Aircrack-ng is the standard tool for cracking WEP keys by capturing IVs. Reaver is for WPS, Kismet is a sniffer, and John the Ripper is a general password cracker.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Aircrack-ng
Why this is correct
Aircrack-ng is specifically engineered to exploit the cryptographic weaknesses inherent in the WEP protocol, primarily by collecting a sufficient number of Initialization Vectors (IVs). It leverages statistical attacks, such as the FMS attack, to deduce the WEP key from patterns observed in these IVs, which are often reused or predictable due to WEP's design flaws. The tool then performs a brute-force or dictionary attack on the derived key space, making it highly effective when a large volume of IVs has been captured.
- ✗
Reaver
Why it's wrong here
Reaver is a specialized tool designed to exploit vulnerabilities in the Wi-Fi Protected Setup (WPS) protocol, specifically by brute-forcing the WPS PIN. This attack vector targets the WPS authentication mechanism, which is entirely distinct from the WEP encryption scheme. Consequently, Reaver is ineffective for cracking WEP keys, as it does not analyze Initialization Vectors (IVs) or exploit the RC4 stream cipher weaknesses that WEP relies upon.
- ✗
Kismet
Why it's wrong here
Kismet functions primarily as a passive wireless network detector, sniffer, and intrusion detection system, designed to identify access points and clients, and capture raw network traffic. While it can certainly capture Initialization Vectors (IVs) as part of its data collection capabilities, Kismet lacks the active cracking algorithms necessary to analyze these IVs and deduce a WEP key. Its role is observational and data-gathering, not active cryptographic exploitation.
- ✗
John the Ripper
Why it's wrong here
John the Ripper is a versatile password cracking tool primarily used for offline brute-force and dictionary attacks against various password hash formats, such as those found in Unix /etc/shadow files or database dumps. Its methodology involves comparing candidate passwords against known hashes, a process fundamentally different from exploiting the real-time cryptographic weaknesses of the WEP protocol. WEP cracking requires analysis of live network traffic and Initialization Vectors (IVs), not static password hashes.
Go deeper
Related to this question
About these practice questions
Courseiva writes every CEH question from scratch — 870 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
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.