The correct answer is a brute force attack on the SSH service because the logs show repeated failed login attempts from a single IP address, which is the hallmark of automated credential guessing. This pattern directly indicates an attacker systematically trying username and password combinations to gain unauthorized access, distinguishing it from other threats like phishing, which relies on deception, or a denial-of-service attack, which would flood the service with traffic rather than login attempts. On the ISC2 Certified in Cybersecurity CC exam, this question tests your ability to interpret security logs and map observed events to specific attack types—a core skill for incident identification. A common trap is confusing repeated failures with a DoS, but remember that brute force attacks focus on authentication attempts, not overwhelming system resources. For a quick memory tip, think “SSH fails = brute force nails” to link the log pattern directly to the attack.
ISC2 CC Security Operations Practice Question
This CC practice question tests your understanding of security operations. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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
Refer to the exhibit.
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$ cat /var/log/syslog | grep "sshd"
Apr 10 03:22:15 server1 sshd[12345]: Failed password for root from 10.0.0.99 port 22 ssh2
Apr 10 03:22:17 server1 sshd[12346]: Failed password for root from 10.0.0.99 port 22 ssh2
Apr 10 03:22:19 server1 sshd[12347]: Failed password for admin from 10.0.0.99 port 22 ssh2
Apr 10 03:22:21 server1 sshd[12348]: Failed password for admin from 10.0.0.99 port 22 ssh2
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A security analyst observes these SSH logs. What is the MOST likely attack?
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.
Refer to the exhibit.
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$ cat /var/log/syslog | grep "sshd"
Apr 10 03:22:15 server1 sshd[12345]: Failed password for root from 10.0.0.99 port 22 ssh2
Apr 10 03:22:17 server1 sshd[12346]: Failed password for root from 10.0.0.99 port 22 ssh2
Apr 10 03:22:19 server1 sshd[12347]: Failed password for admin from 10.0.0.99 port 22 ssh2
Apr 10 03:22:21 server1 sshd[12348]: Failed password for admin from 10.0.0.99 port 22 ssh2
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A
Brute force attack on SSH service
Multiple failed attempts from a single IP.
B
Session hijacking via SSH
Why wrong: Session hijacking would not produce failed password logs.
C
Phishing attack targeting root and admin accounts
Why wrong: Phishing would not appear in SSH logs.
D
Denial of service attack on port 22
Why wrong: DoS would flood connections, not just failed logins.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Brute force attack on SSH service
Option B is correct because repeated failed login attempts from the same IP indicate a brute force attack. Option A is phishing. Option C is SSH hijacking. Option D is a DoS, but not evident.
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.
✓
Brute force attack on SSH service
Why this is correct
Multiple failed attempts from a single IP.
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.
✗
Session hijacking via SSH
Why it's wrong here
Session hijacking would not produce failed password logs.
DoS would flood connections, not just failed logins.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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
An employee at a financial services firm receives an email that appears to come from the IT helpdesk, asking them to reset their password via a link. The link leads to a convincing fake portal that harvests credentials. Security teams use phishing simulations and security-awareness training to reduce this attack vector. Questions like this test whether you can identify social engineering techniques and appropriate controls.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CC question in full detail.
Identify which CC exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Security Operations — This question tests Security Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Brute force attack on SSH service — Option B is correct because repeated failed login attempts from the same IP indicate a brute force attack. Option A is phishing. Option C is SSH hijacking. Option D is a DoS, but not evident.
What should I do if I get this CC question wrong?
Identify which CC exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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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