The answer is that the IPS sensor lacks signatures for the C2 protocol and SSL deep inspection is not enabled. Without SSL deep inspection, the FortiGate cannot decrypt HTTPS traffic, so the IPS engine only sees encrypted packets and cannot match application-layer signatures for command and control traffic. This is why IPS fails to detect C2 traffic even when it is known to be present. On the Fortinet NSE 7 Advanced Security NSE7 exam, this concept tests your understanding that IPS operates on decrypted content—a common trap is assuming IPS can inspect encrypted sessions by default. Remember that signatures alone are useless if the traffic is encrypted; you must pair them with SSL inspection. Memory tip: "No decrypt, no detect—SSL inspection is the key to seeing C2."
NSE7 Advanced Threat Protection Practice Question
This NSE7 practice question tests your understanding of advanced threat protection. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
An administrator is investigating a security incident where a workstation is communicating with a known command and control (C2) server. The FortiGate has IPS enabled but did not block the traffic. Which TWO configuration issues could explain why the IPS did not detect the C2 communication? (Choose two.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The firewall policy does not have SSL deep inspection enabled
Option A is correct because without SSL deep inspection, the FortiGate cannot decrypt HTTPS traffic to inspect the payload for C2 signatures. IPS operates on decrypted content; if the C2 communication uses TLS, the IPS engine only sees encrypted packets and cannot match application-layer signatures. Enabling SSL deep inspection with a valid CA certificate is required to decrypt and inspect the traffic.
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.
✓
The firewall policy does not have SSL deep inspection enabled
Why this is correct
Without SSL inspection, encrypted C2 traffic is invisible to IPS.
Related concept
Read the scenario before looking for a memorised answer.
✗
The IPS sensor is configured in 'Inline' mode
Why it's wrong here
Inline mode allows blocking, not a reason for no detection.
✗
The IPS sensor has 'Logging' disabled
Why it's wrong here
Logging disabled still allows detection, just no logs.
✓
The IPS sensor does not include signatures for the C2 protocol or pattern
Why this is correct
If no relevant signature, detection will not occur.
Related concept
Read the scenario before looking for a memorised answer.
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume 'Inline' mode or 'Transparent' mode inherently affect detection capability, when in fact they only affect traffic flow or logging, not the IPS engine's ability to inspect decrypted content.
Detailed technical explanation
How to think about this question
SSL deep inspection requires the FortiGate to act as a man-in-the-middle, re-encrypting traffic with a locally generated certificate. Without it, the IPS engine sees only TLS handshake metadata and encrypted application data, making signature matching impossible for protocols like HTTP/2 or custom C2 protocols running over TLS. In real-world scenarios, many C2 frameworks (e.g., Cobalt Strike) use HTTPS with valid certificates, so deep inspection is critical for detection.
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 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.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Advanced Threat Protection — This question tests Advanced Threat Protection — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The firewall policy does not have SSL deep inspection enabled — Option A is correct because without SSL deep inspection, the FortiGate cannot decrypt HTTPS traffic to inspect the payload for C2 signatures. IPS operates on decrypted content; if the C2 communication uses TLS, the IPS engine only sees encrypted packets and cannot match application-layer signatures. Enabling SSL deep inspection with a valid CA certificate is required to decrypt and inspect the traffic.
What should I do if I get this NSE7 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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