easyMultiple ChoiceObjective-mapped
CAS-004 Practice Question: Is reviewing firewall logs and finds multiple…
A security engineer is reviewing firewall logs and finds multiple failed SSH attempts from an internal IP. Which control should be implemented to reduce this risk?
⚠ Common exam trap
It's easy for candidates to choose a network-based control like subnet restriction (Option A) because it seems logical to limit access, but they overlook that the failed attempts are already coming from an internal IP, meaning the attacker is already inside the trusted zone and subnet filtering alone will not stop the attack.
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
✓
Implement account lockout after 5 failed attempts
Implementing an account lockout policy after a defined number of failed attempts (e.g., 5) directly mitigates brute-force or password-guessing attacks against SSH. This control enforces a threshold that stops automated scripts or manual attempts from continuing, reducing the risk of unauthorized access without blocking legitimate administrative traffic.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Allow SSH only from a specific management subnet
Why it's wrong here
This reduces the attack surface but does not address the failed attempts from an already allowed IP.
- ✓
Implement account lockout after 5 failed attempts
Why this is correct
Account lockout prevents brute-force attacks by temporarily disabling the account.
- ✗
Install a host-based IDS on the server
Why it's wrong here
HIDS can detect but not prevent brute-force attacks.
- ✗
Disable SSH and use Telnet instead
Why it's wrong here
Telnet is unencrypted and less secure than SSH.
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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.