SK0-005 security-disaster-recovery Practice Question
Exhibit
Apr 25 03:14:22 server sshd[1234]: Failed password for root from 192.168.1.100 port 22 ssh2 Apr 25 03:14:23 server sshd[1234]: Failed password for root from 192.168.1.100 port 22 ssh2 Apr 25 03:14:24 server sshd[1234]: Failed password for root from 192.168.1.100 port 22 ssh2 Apr 25 03:14:25 server sshd[1234]: Failed password for root from 192.168.1.100 port 22 ssh2 Apr 25 03:14:26 server sshd[1234]: Failed password for admin from 192.168.1.100 port 22 ssh2 Apr 25 03:14:27 server sshd[1234]: Failed password for admin from 192.168.1.100 port 22 ssh2 Apr 25 03:14:28 server sshd[1234]: Accepted password for admin from 192.168.1.100 port 22 ssh2 Apr 25 03:14:29 server sshd[1234]: Failed password for root from 192.168.1.101 port 22 ssh2
Refer to the exhibit. A server administrator is reviewing security logs after a suspected brute-force attack on the SSH service. The following excerpt from /var/log/secure is displayed. Which security control would have been MOST effective in preventing the successful login?
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
✓
Implementing fail2ban or similar intrusion prevention.
Option B is correct because fail2ban or a similar intrusion prevention system monitors logs for repeated failures and blocks the attacker's IP address after a configurable number of attempts, stopping the attack before the correct password is guessed. Option A is wrong because a strong password policy might resist guessing for a long time, but the admin password was eventually guessed; it does not actively prevent repeated attempts. Option C is wrong because disabling root login would not have prevented the attack on the admin account, which was the one compromised. Option D is wrong because changing the SSH port is security through obscurity and does not prevent brute-force attempts once the port is discovered.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Disabling root login via SSH.
Why it's wrong here
Disabling root would stop attacks on root, but the shown compromise occurred on the 'admin' account; this control does not address the successful breach of a non-root user.
- ✓
Implementing fail2ban or similar intrusion prevention.
Why this is correct
fail2ban tracks authentication failures and temporarily or permanently bans IPs that exceed the threshold, which would have blocked 192.168.1.100 after the initial failures, preventing the successful login.
- ✗
Enforcing a strong password policy.
Why it's wrong here
Strong passwords reduce the likelihood of quick guesses, but if the password is eventually discovered through repeated attempts (as shown for 'admin'), the attack still succeeds without a lockout mechanism.
- ✗
Using a different SSH port.
Why it's wrong here
Changing the default port may reduce automated scans but does not stop a targeted brute-force attack once the port is known (as indicated by port 22 in the log).
Go deeper
Related to this question
Learn chapter
Operating System Installation and Configuration
Key term
Security
Security in IT is the practice of protecting systems, networks, and data from unauthorized access, damage, or theft.
Key term
Intrusion Prevention System
An Intrusion Prevention System (IPS) is a network security tool that monitors network traffic and actively blocks threats like malware and cyberattacks in real time.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed July 2026 · checked against the official CompTIA exam blueprint
This SK0-005 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 SK0-005 exam.