CISSP Security Architecture and Engineering Practice Question
This CISSP practice question tests your understanding of security architecture and engineering. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
Feb 10 10:23:45 server sshd[1234]: Failed password for root from 192.168.1.100 port 22 ssh2
Feb 10 10:23:48 server sshd[1234]: Failed password for root from 192.168.1.100 port 22 ssh2
Feb 10 10:23:50 server sshd[1234]: Failed password for root from 192.168.1.100 port 22 ssh2
Refer to the exhibit. A security analyst finds these logs on a Linux server. What is the most likely cause of these events?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Feb 10 10:23:45 server sshd[1234]: Failed password for root from 192.168.1.100 port 22 ssh2
Feb 10 10:23:48 server sshd[1234]: Failed password for root from 192.168.1.100 port 22 ssh2
Feb 10 10:23:50 server sshd[1234]: Failed password for root from 192.168.1.100 port 22 ssh2
A
The root account is disabled
Why wrong: If disabled, attempts would not generate failure logs as shown.
B
The firewall is blocking port 22
Why wrong: If blocked, the connection would not reach sshd.
C
A brute-force attack is in progress
Correct. Repeated failed passwords from same IP indicate brute-force.
D
The SSH service is not running
Why wrong: If not running, there would be no sshd process to log.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A brute-force attack is in progress
The logs show repeated SSH authentication failures from the same source IP address with different usernames, including root, admin, and user. This pattern of multiple failed login attempts in rapid succession is characteristic of a brute-force attack against the SSH service. The fact that attempts continue across different usernames indicates an automated tool is systematically trying credentials, not a single misconfiguration or network issue.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The root account is disabled
Why it's wrong here
If disabled, attempts would not generate failure logs as shown.
✗
The firewall is blocking port 22
Why it's wrong here
If blocked, the connection would not reach sshd.
✓
A brute-force attack is in progress
Why this is correct
Correct. Repeated failed passwords from same IP indicate brute-force.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The SSH service is not running
Why it's wrong here
If not running, there would be no sshd process to log.
Common exam traps
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the distinction between a service being unreachable (firewall blocking or service down) versus a service being reachable but under attack, where logs show authentication failures rather than connection failures.
Trap categories for this question
Command / output trap
If disabled, attempts would not generate failure logs as shown.
Detailed technical explanation
How to think about this question
SSH brute-force attacks typically use tools like Hydra or Medusa that cycle through username/password combinations. The SSH daemon (sshd) logs each authentication attempt via syslog, and failed attempts are recorded with 'Failed password' messages. In real-world scenarios, attackers often target common usernames (root, admin, user) first, and rate-limiting or fail2ban can mitigate such attacks by temporarily blocking IPs after a threshold of failures.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CISSP question in full detail.
Security Architecture and Engineering — This question tests Security Architecture and Engineering — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: A brute-force attack is in progress — The logs show repeated SSH authentication failures from the same source IP address with different usernames, including root, admin, and user. This pattern of multiple failed login attempts in rapid succession is characteristic of a brute-force attack against the SSH service. The fact that attempts continue across different usernames indicates an automated tool is systematically trying credentials, not a single misconfiguration or network issue.
What should I do if I get this CISSP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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