Quick Answer
The answer is FTP, or File Transfer Protocol, which transmits unencrypted credentials in cleartext over a network. This occurs because FTP’s authentication process sends the username and password without any encryption, making them easily readable by anyone capturing network traffic with a packet sniffer. On the ISC2 Certified in Cybersecurity CC exam, this question tests your understanding of cleartext protocol vulnerabilities, often contrasting FTP with secure alternatives like SFTP or FTPS. A common trap is confusing FTP with SSH-based protocols, but remember that FTP’s lack of encryption is its defining weakness. To recall this, use the mnemonic “FTP: Files Transmitted Plainly,” reinforcing that its credentials are sent in the clear and vulnerable to capture.
This CC practice question tests your understanding of network security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
During a security assessment, a penetration tester captures unencrypted credentials over the network. Which protocol is most likely being used?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
SMTPS
Why wrong: SMTPS encrypts email submission, protecting credentials in transit.
SSH
Why wrong: SSH encrypts the entire session, protecting credentials.
FTP
FTP sends username and password in plaintext over the network.
HTTPS
Why wrong: HTTPS encrypts all traffic, including credentials.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
FTP
FTP (File Transfer Protocol) transmits data, including credentials, in cleartext over the network. When a penetration tester captures unencrypted credentials, FTP is a likely candidate because it does not encrypt the authentication process, making it vulnerable to packet sniffing attacks.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
SMTPS
Why it's wrong here
SMTPS encrypts email submission, protecting credentials in transit.
SSH
Why it's wrong here
SSH encrypts the entire session, protecting credentials.
FTP
Why this is correct
FTP sends username and password in plaintext over the network.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
HTTPS
Why it's wrong here
HTTPS encrypts all traffic, including credentials.
Common exam traps
ISC2 often tests the distinction between protocols that use encryption (like HTTPS, SSH, SMTPS) and those that do not (like FTP, Telnet, HTTP), and the trap here is that candidates may confuse FTP with its secure variants (FTPS or SFTP) or assume all file transfer protocols are encrypted.
Detailed technical explanation
FTP uses TCP port 21 for control commands and port 20 for data transfer, both in plaintext. The USER and PASS commands are sent without encryption, allowing any attacker with a packet sniffer (e.g., Wireshark) to extract credentials directly from the TCP payload. In contrast, FTPS (FTP over SSL/TLS) or SFTP (SSH File Transfer Protocol) would encrypt this exchange.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Network Security — This question tests Network Security — Read the scenario before looking for a memorised answer..
The correct answer is: FTP — FTP (File Transfer Protocol) transmits data, including credentials, in cleartext over the network. When a penetration tester captures unencrypted credentials, FTP is a likely candidate because it does not encrypt the authentication process, making it vulnerable to packet sniffing attacks.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
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.
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