CAS-004 Security Engineering Practice Question
An organization is implementing SSH hardening for server access. Which configuration change most effectively reduces the attack surface against brute-force and credential theft?
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
✓
Enable public-key authentication and disable password authentication.
Disabling password authentication and requiring key-based authentication eliminates the risk of password brute-force attacks and credential theft via phishing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Change the default SSH port from 22 to a high-numbered port.
Why it's wrong here
Security through obscurity; attackers can still scan ports.
- ✓
Enable public-key authentication and disable password authentication.
Why this is correct
Key-based auth is resistant to brute-force and phishing.
- ✗
Set MaxAuthTries to 6 to limit login attempts.
Why it's wrong here
While helpful, it does not prevent credential theft as effectively as disabling passwords.
- ✗
Use TCP wrappers to restrict source IP addresses.
Why it's wrong here
IP restrictions are useful but can be bypassed; does not protect against compromised credentials.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CAS-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 CAS-005 exam.