- A
PermitRootLogin yes
Why wrong: Allows root login, less secure.
- B
PermitRootLogin no
Prevents direct root login.
- C
Protocol 1
Why wrong: Protocol 1 is insecure; use Protocol 2 only.
- D
PasswordAuthentication no
Disables password auth, forces key-based.
- E
Port 22
Why wrong: Default port, not hardening.
Question 85 of 1,000
XK0-005 Security Practice Question
This XK0-005 practice question tests your understanding of 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.
An administrator needs to harden SSH access. Which TWO settings in /etc/ssh/sshd_config are recommended to improve security? (Choose two.)
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
✓
PermitRootLogin no
Option B is correct because setting `PermitRootLogin no` disables direct root login via SSH, forcing administrators to log in as a regular user and then use `su` or `sudo` for privileged commands. This prevents attackers from targeting the root account directly and ensures all root-level actions are logged under the individual user's session. Option D is correct because setting `PasswordAuthentication no` disables password-based authentication, requiring the use of SSH key pairs, which are resistant to brute-force attacks and credential stuffing.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
PermitRootLogin yes
Why it's wrong here
Allows root login, less secure.
- ✓
PermitRootLogin no
Why this is correct
Prevents direct root login.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Protocol 1
Why it's wrong here
Protocol 1 is insecure; use Protocol 2 only.
- ✓
PasswordAuthentication no
Why this is correct
Disables password auth, forces key-based.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Port 22
Why it's wrong here
Default port, not hardening.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often think changing the default SSH port (Option E) is a strong security measure, but the exam considers it a weak control compared to disabling root login and password authentication, which directly address authentication vulnerabilities.
Detailed technical explanation
How to think about this question
Under the hood, `PasswordAuthentication no` forces the SSH server to reject any authentication method that sends a password over the wire, relying instead on public key authentication (RFC 4252). This eliminates the risk of password interception and offline brute-forcing of the SSH service. In real-world scenarios, even with key-based authentication, administrators should also consider disabling `ChallengeResponseAuthentication` and `UsePAM` if not needed, as they can reintroduce password-based paths.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this XK0-005 question test?
Security — This question tests Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: PermitRootLogin no — Option B is correct because setting `PermitRootLogin no` disables direct root login via SSH, forcing administrators to log in as a regular user and then use `su` or `sudo` for privileged commands. This prevents attackers from targeting the root account directly and ensures all root-level actions are logged under the individual user's session. Option D is correct because setting `PasswordAuthentication no` disables password-based authentication, requiring the use of SSH key pairs, which are resistant to brute-force attacks and credential stuffing.
What should I do if I get this XK0-005 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
This XK0-005 practice question is part of Courseiva's free CompTIA 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 XK0-005 exam.
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