The correct answer is that the computer is infected with malware communicating with a command-and-control server. This conclusion is drawn from the netstat output, which reveals multiple established connections from the local machine to the same remote IP address on port 443, a pattern classic to botnet behavior where malware phones home to receive instructions. On the CompTIA ITF+ FC0-U61 exam, this scenario tests your ability to detect malware command and control using netstat, a key skill for identifying suspicious network activity. A common trap is confusing this with a DoS attack, but remember that DoS floods from many sources, while malware command-and-control typically shows repeated connections to a single IP. Memory tip: think "one IP, many connections" equals a botnet infection.
FC0-U61 Security Practice Question
This FC0-U61 practice question tests your understanding of security. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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.
C:\Users\Admin> netstat -an | find "ESTABLISHED"
TCP 192.168.1.10:49152 203.0.113.5:443 ESTABLISHED
TCP 192.168.1.10:49153 203.0.113.5:443 ESTABLISHED
TCP 192.168.1.10:49154 203.0.113.5:443 ESTABLISHED
TCP 192.168.1.10:49155 203.0.113.5:443 ESTABLISHED
A user reports that their computer is running slowly and the network activity light is constantly on. The technician runs the command shown in the exhibit. Based on the output, what is the most likely cause?
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.
C:\Users\Admin> netstat -an | find "ESTABLISHED"
TCP 192.168.1.10:49152 203.0.113.5:443 ESTABLISHED
TCP 192.168.1.10:49153 203.0.113.5:443 ESTABLISHED
TCP 192.168.1.10:49154 203.0.113.5:443 ESTABLISHED
TCP 192.168.1.10:49155 203.0.113.5:443 ESTABLISHED
A
The computer is experiencing a denial-of-service (DoS) attack
Why wrong: A DoS attack usually involves numerous connections from different sources, not all to the same IP.
B
The computer is infected with malware communicating with a command-and-control server
Multiple connections to the same remote server are a sign of botnet or C2 activity.
C
The user is running excessive web browsing sessions
Why wrong: Web browsing would show connections to various IPs, not a single IP repeatedly.
D
The firewall is misconfigured and blocking legitimate traffic
Why wrong: Firewall misconfiguration would not cause multiple established connections; it would block or permit.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The computer is infected with malware communicating with a command-and-control server
The exhibit shows multiple established connections from the local computer to the same remote IP on port 443 (HTTPS). This pattern suggests a botnet or malware establishing multiple command-and-control channels. Option B is correct because it indicates a malware infection. Option A is wrong because a DoS attack would typically show many connections from different sources. Option C wrong because a firewall misconfiguration would block or allow traffic, not create multiple connections. Option D wrong because excessive web browsing would show connections to various IPs, not just one.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 computer is experiencing a denial-of-service (DoS) attack
Why it's wrong here
A DoS attack usually involves numerous connections from different sources, not all to the same IP.
✓
The computer is infected with malware communicating with a command-and-control server
Why this is correct
Multiple connections to the same remote server are a sign of botnet or C2 activity.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
✗
The user is running excessive web browsing sessions
Why it's wrong here
Web browsing would show connections to various IPs, not a single IP repeatedly.
✗
The firewall is misconfigured and blocking legitimate traffic
Why it's wrong here
Firewall misconfiguration would not cause multiple established connections; it would block or permit.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Trap categories for this question
Command / output trap
Web browsing would show connections to various IPs, not a single IP repeatedly.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related FC0-U61 NAT questions on configuration and troubleshooting.
Security — This question tests Security — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The computer is infected with malware communicating with a command-and-control server — The exhibit shows multiple established connections from the local computer to the same remote IP on port 443 (HTTPS). This pattern suggests a botnet or malware establishing multiple command-and-control channels. Option B is correct because it indicates a malware infection. Option A is wrong because a DoS attack would typically show many connections from different sources. Option C wrong because a firewall misconfiguration would block or allow traffic, not create multiple connections. Option D wrong because excessive web browsing would show connections to various IPs, not just one.
What should I do if I get this FC0-U61 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related FC0-U61 NAT questions on configuration and troubleshooting.
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?
Static NAT maps one inside address to one outside address.
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