XK0-006 Security Practice Question
A system administrator is hardening SSH and needs to disable root login and password authentication. Which two directives should be set in /etc/ssh/sshd_config?
⚠ Common exam trap
A common mix-up: candidates confuse ChallengeResponseAuthentication with PasswordAuthentication, or assume DenyUsers is a valid directive for blocking root, when the correct syntax is PermitRootLogin no.
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 and PasswordAuthentication no
Disabling root login and password authentication are two separate directives in sshd_config. PermitRootLogin no prevents direct SSH access for the root user, and PasswordAuthentication no disables password-based logins, forcing the use of key-based authentication. Both directives are required to meet the hardening goal.
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 no and ChallengeResponseAuthentication no
Why it's wrong here
ChallengeResponseAuthentication is different from PasswordAuthentication.
- ✗
DenyUsers root and PasswordAuthentication no
Why it's wrong here
DenyUsers is not a valid sshd_config directive.
- ✓
PermitRootLogin no and PasswordAuthentication no
Why this is correct
These two settings disable root login and password auth.
- ✗
PermitRootLogin prohibit-password and PasswordAuthentication yes
Why it's wrong here
This allows root login with keys, but password auth is enabled.
Go deeper
Related to this question
Learn chapter
User and Group Administration
Key term
User
A user is any person, system, or device that interacts with an IT service, resource, or identity system, typically authenticated through credentials and authorized to perform specific actions.
Key term
SSH
SSH (Secure Shell) is a cryptographic network protocol that provides secure, encrypted communication and remote administration between two devices over an unsecured network.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This XK0-006 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 XK0-006 exam.