The correct scenario is that an internal host is compromised and attacking an external web server. This conclusion is drawn from log analysis showing the internal IP 10.0.1.100 first attempting a denied connection to port 80 (HTTP), then switching to port 443 (HTTPS) which bypassed the firewall, followed by SQL injection attempts against the external server—a classic pattern of a compromised host adapting its attack vector to evade detection. On the CompTIA SecurityX CAS-004 exam, this question tests your ability to correlate firewall logs with application-layer attacks, distinguishing between inbound threats and outbound malicious activity from an internal asset. A common trap is assuming all SQL injection originates externally, but the key clue is the denied-to-allowed port shift, which indicates the internal host is actively probing for an open path. Memory tip: think “denied HTTP, allowed HTTPS, then injection” as the three-step signature of a compromised host pivoting to attack outward.
CAS-004 Security Operations Practice Question
This CAS-004 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.
```
[timestamp] firewall: Deny TCP 10.0.1.100:54321 -> 203.0.113.5:80 (Drop)
[timestamp] firewall: Allow TCP 10.0.1.100:54322 -> 203.0.113.5:443 (Allow)
[timestamp] IDS: Alert - SQL Injection attempt detected from 10.0.1.100 to 203.0.113.5:443
[timestamp] web_server: HTTP POST /login.php with sql_injection_pattern
```
Given the exhibit, what is the MOST likely scenario?
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
✓
An internal host is compromised and attacking an external web server.
Option C is correct. The internal host 10.0.1.100 initially tried to connect to port 80 (HTTP) but was denied, then used port 443 (HTTPS) which was allowed, and then performed SQL injection on the web server. This suggests the host is compromised and attempting to attack an external server via HTTPS to bypass firewall rules. Option A is wrong because the traffic is outward, not inbound. Option B is wrong because SQL injection is detected, and the pattern is deliberate. Option D is wrong because host is active.
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.
✗
A misconfigured application is sending malformed data to a server.
Why it's wrong here
The pattern of SQL injection is intentional, not misconfiguration.
✗
An external attacker is scanning the internal network.
An internal host is compromised and attacking an external web server.
Why this is correct
The host adapts to firewall rules and launches SQL injection attack.
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.
✗
A web vulnerability scanner is performing authorized tests.
Why it's wrong here
The SQL injection alert suggests malicious intent, and there's no authorization indication.
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.
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 CAS-004 NAT questions on configuration and troubleshooting.
Security Operations — This question tests Security Operations — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: An internal host is compromised and attacking an external web server. — Option C is correct. The internal host 10.0.1.100 initially tried to connect to port 80 (HTTP) but was denied, then used port 443 (HTTPS) which was allowed, and then performed SQL injection on the web server. This suggests the host is compromised and attempting to attack an external server via HTTPS to bypass firewall rules. Option A is wrong because the traffic is outward, not inbound. Option B is wrong because SQL injection is detected, and the pattern is deliberate. Option D is wrong because host is active.
What should I do if I get this CAS-004 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 CAS-004 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.
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 →
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.
This CAS-004 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 CAS-004 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.