ISC2 CC Network Security Practice Question
Which protocol is considered insecure because it transmits data, including passwords, in cleartext, and its use should be avoided in favor of more secure alternatives?
⚠ Common exam trap
The trap is picking a protocol that sounds old or file-related (like SFTP) instead of recognizing that Telnet is the classic cleartext remote-access protocol.
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
✓
Telnet
Telnet transmits all data, including usernames and passwords, in cleartext over the network, making it trivial to intercept with packet capture. It lacks encryption and integrity protection, so it is considered insecure and should be replaced by SSH for remote administration. This is why Telnet is the correct answer.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
SSH
Why it's wrong here
SSH encrypts the session and is the transport underlying secure alternatives such as SFTP and SCP, so it does not transmit credentials in cleartext. It tempts because it shares a name with the insecure protocol the question describes, namely Telnet, which sends passwords unencrypted.
- ✗
SFTP
Why it's wrong here
SFTP runs over SSH and encrypts the entire session, including credentials, so it is a secure replacement rather than the insecure protocol described. It tempts because the name resembles FTP, the cleartext protocol the question targets, which sends passwords unencrypted.
- ✗
HTTPS
Why it's wrong here
HTTPS encrypts traffic with TLS, so it never transmits passwords in cleartext; the stem describes a protocol lacking transport encryption. It is tempting because HTTPS is the secure replacement for exactly this weakness, making it the correct answer when a question asks which protocol should be used instead of an insecure one.
- ✓
Telnet
Why this is correct
Telnet sends all session traffic, including login credentials, as unencrypted cleartext across the network, so anyone capturing packets reads them directly. SSH replaces it by encrypting the same terminal access, which is why Telnet should be disabled on managed devices.
Go deeper
Related to this question
Learn chapter
Secure Network Architecture and Design
Key term
Encryption
Encryption is the process of converting readable data into a secret code to prevent unauthorized access.
Key term
Integrity
Integrity is the assurance that data has not been altered or tampered with in an unauthorized way, preserving its accuracy and consistency from source to destination.
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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 ISC2 exam blueprint
This CC practice question is part of Courseiva's free ISC2 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 CC exam.