This CISM practice question tests your understanding of incident management. Compare every option against the stated constraints before choosing — the best answer satisfies all requirements, not just the most obvious one. 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
[IDS Alert] Signature: ET TROJAN Known Botnet C2 1
Source: 10.0.1.50:443 -> Destination: 203.0.113.5:8080
Payload: [encrypted]
Refer to the exhibit. An analyst sees this alert on the network. What is the most appropriate immediate action?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Investigate the source endpoint for compromise
The source IP is internal, so the analyst should investigate the internal system for compromise.
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.
✗
Ignore the alert as it is likely false positive
Why it's wrong here
Ignoring could miss a real incident; the alert should be verified.
✓
Investigate the source endpoint for compromise
Why this is correct
Correct: The internal system is likely compromised and needs examination.
Related concept
Static NAT maps one inside address to one outside address.
✗
Block the source IP 10.0.1.50
Why it's wrong here
Blocking the internal IP may disrupt legitimate services without investigation.
✗
Block the destination IP 203.0.113.5
Why it's wrong here
Blocking the external IP may help but immediate response should focus on internal.
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 CISM NAT questions on configuration and troubleshooting.
Incident Management — This question tests Incident Management — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Investigate the source endpoint for compromise — The source IP is internal, so the analyst should investigate the internal system for compromise.
What should I do if I get this CISM 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 CISM NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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Question Discussion
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