CEH Wireless, IoT and Cloud Security Practice Question
During a wireless penetration test, you discover that the target network uses WPA2-Enterprise with PEAP-MSCHAPv2. You capture the authentication traffic of a legitimate user. Which attack can you perform to recover the user's domain credentials?
⚠ Common exam trap
Test-takers frequently confuse WPA2-Enterprise with WPA2-Personal and incorrectly apply attacks like PMKID or handshake decryption, not realizing that enterprise mode relies on RADIUS-based authentication and is vulnerable to rogue server attacks rather than PSK cracking.
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
✓
Set up a rogue RADIUS server to capture the challenge-response and perform an offline brute-force attack.
In WPA2-Enterprise with PEAP-MSCHAPv2, the authentication is based on a challenge-response mechanism between the client and a RADIUS server. By setting up a rogue RADIUS server, you can capture the challenge and the client's encrypted response, then perform an offline brute-force attack against the MSCHAPv2 hash to recover the user's domain credentials. This works because the MSCHAPv2 response is derived from the user's password and can be cracked offline.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Decrypt the traffic using the captured handshake to get the credentials.
Why it's wrong here
In a WPA2-Enterprise environment, the captured EAPOL handshake frames do not contain the user's plaintext credentials or a directly crackable hash of them for offline decryption of *traffic*. While the Pairwise Master Key (PMK) is derived during the EAP authentication process, it is used to generate session keys for encrypting data traffic, not to directly decrypt the initial EAP exchange to reveal user credentials. The EAP tunnel itself is established and encrypted *before* the PMK is fully derived for data encryption, making direct credential extraction from the handshake for traffic decryption impossible.
- ✗
WPS PIN brute-force to recover the PSK.
Why it's wrong here
WPS (Wi-Fi Protected Setup) is a feature exclusively designed for WPA/WPA2-Personal networks, which utilize a single Pre-Shared Key (PSK) for all clients. WPA2-Enterprise, conversely, relies on 802.1X authentication with an external RADIUS server and individual user credentials, not a shared PSK or a WPS PIN. Therefore, attempting a WPS PIN brute-force attack is entirely irrelevant and ineffective against an Enterprise-grade wireless network, as the WPS protocol is simply not implemented or supported in such environments.
- ✗
PMKID attack to crack the pre-shared key.
Why it's wrong here
The PMKID attack is specifically designed to recover the Pre-Shared Key (PSK) in WPA/WPA2-Personal networks by capturing the first frame of the 4-way handshake and performing an offline brute-force. This method is inapplicable to WPA2-Enterprise environments because they do not use a single PSK. Instead, Enterprise networks employ 802.1X authentication with individual user credentials and a RADIUS server, meaning there is no PSK to crack via a PMKID attack.
- ✓
Set up a rogue RADIUS server to capture the challenge-response and perform an offline brute-force attack.
Why this is correct
Setting up a rogue RADIUS server is a highly effective attack against WPA2-Enterprise networks. By impersonating the legitimate authentication server, the rogue RADIUS server can trick clients into authenticating against it. During this process, it captures the challenge-response hashes, such as NTLMv2 hashes from PEAP/MSCHAPv2, which are exchanged during the EAP authentication phase. These captured hashes can then be subjected to efficient offline dictionary or brute-force attacks to recover the actual user credentials, providing unauthorized access.
Quick reference
AAA Protocol Comparison
| Protocol | Port(s) | Encryption | Transport | Primary Use |
|---|---|---|---|---|
| RADIUS | 1812 / 1813 | Password only | UDP | Network access control |
| TACACS+ | 49 | Full packet | TCP | Device administration |
| Diameter | 3868 | Full session | TCP / SCTP | Carrier / mobile networks |
| 802.1X | — | EAP-based | Layer 2 | Port-based access control |
TACACS+ encrypts the entire packet; RADIUS only encrypts the password field — a key exam distinction.
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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.