The correct first step is to review DNS logs for outbound connections to unknown destinations. This is because DNS logs act as a directory of every domain a system tries to reach, and data exfiltration via DNS often involves small, encoded queries sent to attacker-controlled servers, making the logs a high-fidelity source for spotting unusual patterns like repeated lookups to suspicious domains or high query volumes. On the Certified Information Security Manager CISM exam, this question tests your ability to prioritize detection over containment during incident response—a common trap is jumping to blocking the domain or resetting passwords, which are later steps that destroy forensic evidence. Remember the mnemonic: **D**etect **N**ow, **S**top later—DNS logs are your first clue.
CISM Incident Management Practice Question
This CISM practice question tests your understanding of incident management. 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.
During a phishing campaign, several employees clicked a malicious link that downloaded a remote access trojan (RAT). The incident response team has isolated the infected endpoints and is analyzing network traffic. They suspect that data may have been exfiltrated but are unsure. The team needs to determine the extent of data exfiltration as quickly as possible. What action should the team take FIRST?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "first"
Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Review DNS logs for outbound connections to unknown destinations
Reviewing DNS logs can reveal connections to known malicious domains or unusual patterns, helping identify data exfiltration. Blocking the domain is a containment step but doesn't aid analysis. Running a network scan may be too broad. Resetting passwords is important but not for detecting exfiltration.
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.
✓
Review DNS logs for outbound connections to unknown destinations
Why this is correct
DNS logs can show queries to command-and-control or exfiltration domains, providing evidence.
Clue confirmation
The clue word "first" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
✗
Block the malicious domain at the firewall
Why it's wrong here
Blocking is containment; it does not help determine if exfiltration occurred.
✗
Reset all employees' passwords
Why it's wrong here
Password reset is a security measure but does not reveal exfiltration activity.
✗
Run a full network scan for open ports
Why it's wrong here
A network scan might find other issues but is not efficient for detecting specific exfiltration.
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: Review DNS logs for outbound connections to unknown destinations — Reviewing DNS logs can reveal connections to known malicious domains or unusual patterns, helping identify data exfiltration. Blocking the domain is a containment step but doesn't aid analysis. Running a network scan may be too broad. Resetting passwords is important but not for detecting exfiltration.
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.
Are there clue words in this question I should notice?
Yes — watch for: "first". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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