The answer is to lock the user account 'jsmith'. This is the correct immediate containment for brute-force credential compromise because the SIEM alert confirms a successful login, meaning the attacker has already obtained valid credentials. Locking the account severs the attacker’s access at the authentication layer, preventing any further exploitation regardless of the source IP. On the Certified Information Security Manager CISM exam, this scenario tests your ability to prioritize containment over eradication or notification—a common trap is choosing to block the IP, which fails if the attacker rotates addresses. Remember the memory tip: “Credentials are the keys; lock the door, not the window.”
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.
Exhibit
Refer to the exhibit.
```
[Alert] Correlation Rule: Multiple Failed Logins
Source IP: 10.0.0.55
Destination IP: 192.168.1.10
Event Count: 150 failed logins to admin account 'jsmith' within 5 minutes
Action: Triggered
```
Based on the SIEM alert exhibit, which immediate action should the incident responder take?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Lock the user account 'jsmith'
The SIEM alert indicates a successful brute-force login from source IP 10.0.0.55 to the destination server using the account 'jsmith'. Locking the user account immediately stops the attacker from further exploiting the compromised credentials, which is the most direct containment action. Blocking the IP alone would not prevent re-authentication if the attacker switches IPs, and contacting the user wastes critical time during an active incident.
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.
✗
Block the source IP 10.0.0.55 at the firewall
Why it's wrong here
Blocking IP is good but may be a temporary measure; locking account is more direct.
✓
Lock the user account 'jsmith'
Why this is correct
Locking the account prevents further brute-force.
Related concept
Read the scenario before looking for a memorised answer.
✗
Increase logging level for the destination server
Why it's wrong here
Increasing logging is not an immediate response.
✗
Contact the user 'jsmith' to verify activity
Why it's wrong here
Verification is important but not immediate; the attack is ongoing.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose to block the source IP, thinking it stops the attack, but fail to realize the attacker already has valid credentials and can pivot from any IP, making account lockout the only effective containment step.
Detailed technical explanation
How to think about this question
In a brute-force attack, the SIEM correlates multiple failed logins (e.g., Event ID 4625 in Windows) followed by a successful login (Event ID 4624). Locking the account invalidates the current Kerberos TGT or NTLM hash, preventing any further authenticated sessions. This aligns with the NIST SP 800-61 incident response containment strategy, where credential compromise requires immediate account disablement rather than network-level controls.
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.
Incident Management — This question tests Incident Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Lock the user account 'jsmith' — The SIEM alert indicates a successful brute-force login from source IP 10.0.0.55 to the destination server using the account 'jsmith'. Locking the user account immediately stops the attacker from further exploiting the compromised credentials, which is the most direct containment action. Blocking the IP alone would not prevent re-authentication if the attacker switches IPs, and contacting the user wastes critical time during an active incident.
What should I do if I get this CISM 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.
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 CISM practice question is part of Courseiva's free ISACA 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 CISM 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.