The correct answer is a denial-of-service (DoS) attack from the internal server to the external host. This log pattern reveals anomalous outbound traffic because an internal web server should typically receive inbound requests, not initiate connections to external hosts. When a server suddenly sends a high volume of packets outward to a single external IP, it strongly indicates the server has been compromised and is being used as a source to flood the target, which is the hallmark of an internal server external outbound traffic attack pattern. On the ISC2 Certified in Cybersecurity CC exam, this scenario tests your ability to recognize that outbound traffic from a server is abnormal and often signals a DoS attack, not a legitimate service. A common trap is assuming all server traffic is safe, but the key is the direction: servers serve in, not attack out. Memory tip: “Servers serve in; attackers send out.”
ISC2 CC Security Operations Practice Question
This CC practice question tests your understanding of security operations. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
```
EdgeRouter# show firewall log
Log for firewall-in
Fri Aug 18 14:23:45 2023 : IN=eth0 OUT=eth1 MAC=00:1a:2b:3c:4d:5e:6f:7a:8b:9c:0d:1e:2f SRC=10.0.1.100 DST=203.0.113.50 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=12345 DF PROTO=TCP SPT=34567 DPT=80 WINDOW=65535 RES=0x00 SYN URGP=0
Fri Aug 18 14:23:46 2023 : IN=eth0 OUT=eth1 MAC=00:1a:2b:3c:4d:5e:6f:7a:8b:9c:0d:1e:2f SRC=10.0.1.100 DST=203.0.113.50 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=12346 DF PROTO=TCP SPT=34568 DPT=80 WINDOW=65535 RES=0x00 SYN URGP=0
Fri Aug 18 14:23:47 2023 : IN=eth0 OUT=eth1 MAC=00:1a:2b:3c:4d:5e:6f:7a:8b:9c:0d:1e:2f SRC=10.0.1.100 DST=203.0.113.50 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=12347 DF PROTO=TCP SPT=34569 DPT=80 WINDOW=65535 RES=0x00 SYN URGP=0
```
An analyst reviews the firewall log exhibit. The source IP 10.0.1.100 is an internal web server. The destination IP 203.0.113.50 is an external host. What does this log pattern MOST likely indicate?
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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A denial-of-service (DoS) attack from the internal server to the external host
The log pattern shows the internal web server (10.0.1.100) sending traffic to an external host (203.0.113.50). In a typical network, internal web servers serve content to internal users, not initiate outbound connections to external hosts. This anomalous outbound traffic pattern, especially if it involves a high volume of packets or connections, is characteristic of a denial-of-service (DoS) attack where the internal server is used as a source to flood the external target, potentially due to compromise or misconfiguration.
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.
✓
A denial-of-service (DoS) attack from the internal server to the external host
Why this is correct
Multiple SYN packets without completion indicate a SYN flood, a type of DoS attack.
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.
✗
A port scan from the internal server to the external host
Why it's wrong here
A port scan would target multiple ports on the destination, but here only port 80 is used.
✗
Normal web traffic from the server to the external host
Why it's wrong here
Normal traffic would show SYN, SYN-ACK, ACK, not repeated SYNs.
✗
An attempted SQL injection attack from the external host to the internal server
Why it's wrong here
SQL injection involves application-layer payload, not just SYN packets; also the direction is internal to external.
Common exam traps
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the candidate's ability to interpret traffic direction and normal vs. anomalous behavior, and the trap here is assuming that any traffic from a web server is legitimate, ignoring that internal servers should not typically initiate outbound connections to external hosts.
Trap categories for this question
Command / output trap
Normal traffic would show SYN, SYN-ACK, ACK, not repeated SYNs.
Detailed technical explanation
How to think about this question
Under the hood, a DoS attack can be launched using a compromised internal server as a source, often via botnet malware or a misconfigured service that allows reflection (e.g., DNS amplification). The firewall log would show a high rate of SYN packets or UDP floods from the internal IP to the external target, potentially exhausting the target's resources. In real-world scenarios, this is often detected by observing asymmetric traffic patterns where internal servers initiate unexpected outbound connections, triggering alerts in SIEM systems.
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 team runs a vulnerability scan on a web application and discovers an unpatched SQL injection flaw. The team prioritises remediation by CVSS score — critical flaws are patched within 24 hours, high within 7 days. Questions like this test whether you understand vulnerability management processes, scanning tools, and remediation prioritisation.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CC question in full detail.
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: A denial-of-service (DoS) attack from the internal server to the external host — The log pattern shows the internal web server (10.0.1.100) sending traffic to an external host (203.0.113.50). In a typical network, internal web servers serve content to internal users, not initiate outbound connections to external hosts. This anomalous outbound traffic pattern, especially if it involves a high volume of packets or connections, is characteristic of a denial-of-service (DoS) attack where the internal server is used as a source to flood the external target, potentially due to compromise or misconfiguration.
What should I do if I get this CC 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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