LPIC-2 System Security Practice Question
Which TWO of the following actions are recommended to improve SSH server security?
⚠ Common exam trap
It's easy for candidates to confuse `PermitEmptyPasswords` with `PasswordAuthentication`, thinking only one is needed, or they mistakenly believe that `AllowUsers` supports wildcard patterns like shell globs, when in fact it only matches exact user names or user@host combinations.
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
✓
PermitEmptyPasswords no
Setting `PermitEmptyPasswords no` in `/etc/ssh/sshd_config` explicitly disallows login attempts with empty passwords, closing a trivial authentication bypass vector. This directive is enforced by the SSH daemon before any PAM or password verification occurs, making it a fundamental hardening step.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
PermitEmptyPasswords no
Why this is correct
Preventing empty passwords eliminates a major vulnerability where an account could have no password set.
- ✓
PasswordAuthentication no
Why this is correct
Disabling password authentication forces key-based authentication, which is more secure against brute-force attacks.
- ✗
AllowUsers *.example.com
Why it's wrong here
Restricting users by domain may reduce exposure but a wildcard domain is broad and not a primary security measure.
- ✗
PermitRootLogin yes
Why it's wrong here
Allowing root login over SSH increases attack surface and is not recommended.
- ✗
UsePAM yes
Why it's wrong here
While PAM is commonly used, its presence alone does not improve security; misconfiguration can be harmful.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LPIC-2 practice question is part of Courseiva's free LPI 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 LPIC-2 exam.