N10-009 Network Security Practice Question
A security auditor is reviewing firewall logs and notices repeated login attempts from a single external IP address to the company's SSH server. Which type of attack is likely occurring?
⚠ Common exam trap
The N10-009 exam often tests the distinction between a brute force attack (repeated single-source login attempts) and a DDoS attack (traffic flood from multiple sources), so candidates mistakenly choose DDoS when they see 'repeated attempts' without recognizing the single-source, credential-guessing nature of the activity.
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
✓
Brute force attack
Repeated login attempts from a single external IP to an SSH server are characteristic of a brute force attack, where an attacker systematically tries many username/password combinations to gain unauthorized access. SSH (port 22) is a common target because it provides remote shell access, and automated tools like Hydra or Medusa can rapidly test credentials. The firewall logs show multiple failed authentication attempts from the same source, which is the hallmark of this attack type.
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
Why this is correct
A brute force attack involves systematically trying numerous combinations of usernames and passwords to gain unauthorized access to a system or service, such as SSH. The firewall logs showing repeated login attempts from a single IP address are a definitive indicator of such an attack, as the attacker is attempting to guess credentials through exhaustive trial and error. This pattern aims to eventually find a valid credential pair rather than exploiting a vulnerability.
- ✗
Man-in-the-middle attack
Why it's wrong here
A man-in-the-middle (MiTM) attack involves an attacker secretly relaying and possibly altering the communication between two parties who believe they are directly communicating with each other. This type of attack focuses on intercepting established sessions or data streams, not on initiating repeated failed login attempts from a single source. Firewall logs would typically show unusual traffic patterns or session hijacking, rather than a high volume of authentication failures.
When this WOULD be correct
A question describing an attacker intercepting SSH traffic between a client and server, possibly using ARP spoofing or a rogue access point, to capture credentials or session data.
- ✗
ARP poisoning
Why it's wrong here
ARP poisoning sends fake ARP replies to associate the attacker's MAC address with the IP of a legitimate device, enabling traffic interception. It occurs on the local network and would not appear as repeated SSH attempts from an external IP.
When this WOULD be correct
A question describing an attacker on the same subnet sending forged ARP replies to associate the attacker's MAC address with the default gateway's IP, causing traffic to be redirected to the attacker, would make ARP poisoning the correct answer.
- ✗
DDoS attack
Why it's wrong here
A Distributed Denial-of-Service (DDoS) attack aims to overwhelm a target system or network resource with a flood of traffic originating from multiple compromised systems, known as a botnet. The objective is to exhaust resources and make the service unavailable to legitimate users, not to gain unauthorized access through login attempts. The scenario describes repeated attempts from a *single* IP, which fundamentally contradicts the 'distributed' nature and typical traffic volume of a DDoS attack.
When this WOULD be correct
A DDoS attack would be correct if the question described a flood of traffic from many distributed sources (e.g., botnet) targeting the SSH server, causing service unavailability, rather than repeated login attempts from one IP.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The N10-009 exam frequently reuses these exact scenarios with slightly different constraints.
✓Brute force attackCorrect answer▾
Why this is correct
A brute force attack involves systematically trying numerous combinations of usernames and passwords to gain unauthorized access to a system or service, such as SSH. The firewall logs showing repeated login attempts from a single IP address are a definitive indicator of such an attack, as the attacker is attempting to guess credentials through exhaustive trial and error. This pattern aims to eventually find a valid credential pair rather than exploiting a vulnerability.
✗Man-in-the-middle attackWrong answer — click to see why▾
Why this is wrong here
A man-in-the-middle attack involves intercepting communication between two parties, not repeated login attempts from a single external IP to an SSH server.
★ When this WOULD be the correct answer
A question describing an attacker intercepting SSH traffic between a client and server, possibly using ARP spoofing or a rogue access point, to capture credentials or session data.
Why candidates choose this
Candidates may confuse repeated login attempts with an active interception attack, or think SSH brute force involves intercepting authentication traffic.
✗ARP poisoningWrong answer — click to see why▾
Why this is wrong here
ARP poisoning operates at Layer 2 by corrupting ARP tables to intercept traffic on a local network, whereas the question describes repeated login attempts from a single external IP to an SSH server, which is a Layer 7 authentication attack.
★ When this WOULD be the correct answer
A question describing an attacker on the same subnet sending forged ARP replies to associate the attacker's MAC address with the default gateway's IP, causing traffic to be redirected to the attacker, would make ARP poisoning the correct answer.
Why candidates choose this
Candidates may confuse network-based attacks like ARP poisoning with brute force attacks, or mistakenly think that repeated login attempts involve intercepting credentials, which is a characteristic of man-in-the-middle attacks, not ARP poisoning.
✗DDoS attackWrong answer — click to see why▾
Why this is wrong here
A DDoS attack aims to overwhelm a service with traffic from multiple sources, causing denial of service. This scenario describes repeated login attempts from a single IP, which is characteristic of a brute force attack, not a DDoS.
★ When this WOULD be the correct answer
A DDoS attack would be correct if the question described a flood of traffic from many distributed sources (e.g., botnet) targeting the SSH server, causing service unavailability, rather than repeated login attempts from one IP.
Why candidates choose this
Candidates may confuse repeated attempts with a denial of service, or think that any high volume of traffic from one source qualifies as DDoS, overlooking the distributed nature requirement.
Analysis generated from the official N10-009blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
Learn chapter
Network Access Control (NAC)
Key term
Security
Security in IT is the practice of protecting systems, networks, and data from unauthorized access, damage, or theft.
Key term
IP address
An IP address is a unique numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.
About these practice questions
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This N10-009 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 N10-009 exam.