Quick Answer
The answer is a brute force password guessing attack. This is correct because the systematic pattern of failed SSH login attempts from a single IP address, spaced 30 seconds apart and targeting different usernames, matches the technical definition of a brute force attack, which tries every possible password combination for each username rather than relying on a precompiled list of likely passwords. On the CISSP exam, this scenario tests your ability to distinguish brute force from dictionary attacks—a common trap is confusing the two, but remember that dictionary attacks use a wordlist, while brute force exhaustively cycles through all possibilities. A key memory tip is to think of brute force as “trying every key on the ring,” whereas a dictionary attack is like “trying only the most common keys.”
This CISSP practice question tests your understanding of security assessment and testing. 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.
A security analyst reviews system logs and notices multiple failed SSH login attempts from a single IP address over the past hour. The attempts are spaced 30 seconds apart and target different usernames. Which type of attack is most likely occurring?
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.
Distributed denial-of-service (DDoS) attack
Why wrong: DDoS aims to overwhelm resources, not login attempts.
Dictionary attack
Why wrong: Dictionary attacks focus on common passwords, but the pattern here is more generic brute force.
Brute force password guessing
Systematic repeated login attempts indicate brute force.
Man-in-the-middle attack
Why wrong: Would not produce login attempts in logs.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Brute force password guessing
The observed pattern—multiple failed SSH login attempts from a single IP, spaced 30 seconds apart, targeting different usernames—is characteristic of a brute force password guessing attack. Unlike a dictionary attack, which uses a precompiled list of likely passwords, a brute force attack systematically tries all possible password combinations for each username, often with a delay to evade rate limiting.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Distributed denial-of-service (DDoS) attack
Why it's wrong here
DDoS aims to overwhelm resources, not login attempts.
Dictionary attack
Why it's wrong here
Dictionary attacks focus on common passwords, but the pattern here is more generic brute force.
Brute force password guessing
Why this is correct
Systematic repeated login attempts 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.
Man-in-the-middle attack
Why it's wrong here
Would not produce login attempts in logs.
Common exam traps
The trap here is confusing a brute force attack with a dictionary attack—the key differentiator is that brute force tries all possible combinations (often with a delay) across multiple usernames, while a dictionary attack uses a precompiled wordlist against a single target username.
Detailed technical explanation
SSH (port 22) logs typically record authentication failures with timestamps and source IPs; a 30-second delay between attempts is a common evasion tactic to bypass fail2ban or similar rate-limiting tools that trigger on rapid bursts. In a real-world scenario, an attacker might use a tool like Hydra or Medusa with a 'brute force' mode, cycling through usernames (e.g., root, admin, user) and passwords, often starting with common usernames before moving to less common ones.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Security Assessment and Testing — study guide chapter
Learn the concepts, then practise the questions
Security Assessment and Testing practice questions
Targeted practice on this topic area only
All CISSP questions
529 questions across all exam domains
Certified Information Systems Security Professional CISSP study guide
Full concept coverage aligned to exam objectives
CISSP practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise CISSP questions linked to Software Development Security.
Practise CISSP questions linked to Security Assessment and Testing.
Practise CISSP questions linked to Identity and Access Management.
Practise CISSP questions linked to Security and Risk Management.
Practise CISSP questions linked to Security Architecture and Engineering.
Practise CISSP questions linked to Communication and Network Security.
Practise CISSP questions linked to Asset Security.
Practise CISSP questions linked to Security Operations.
Practise CISSP questions linked to CISSP fundamentals.
Practise CISSP questions linked to CISSP scenario.
Practise CISSP questions linked to CISSP troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Security Assessment and Testing — This question tests Security Assessment and Testing — Read the scenario before looking for a memorised answer..
The correct answer is: Brute force password guessing — The observed pattern—multiple failed SSH login attempts from a single IP, spaced 30 seconds apart, targeting different usernames—is characteristic of a brute force password guessing attack. Unlike a dictionary attack, which uses a precompiled list of likely passwords, a brute force attack systematically tries all possible password combinations for each username, often with a delay to evade rate limiting.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 24, 2026
This CISSP practice question is part of Courseiva's free ISC2 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 CISSP exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.