hardMultiple Choice
CISM Practice Question: After a security incident, the incident response…
After a security incident, the incident response team identifies that the root cause was a phishing email that bypassed the email filter. The email contained a malicious macro that executed PowerShell commands. Which control would be MOST effective in preventing similar incidents in the future?
⚠ Common exam trap
Many exam-takers choose security awareness training (D) because it seems like a broad solution, but the question asks for the 'most effective' control against a specific technical attack vector, and disabling macros is a direct technical prevention that does not rely on human behavior.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Disable macros in documents originating from external sources
Disabling macros in documents from external sources directly addresses the attack vector: the malicious macro that executed PowerShell commands. This control prevents the macro from running, regardless of the email filter's failure, by blocking the execution environment at the endpoint level. It is a preventive technical control that stops the attack before it can proceed.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Implement network segmentation for sensitive systems
Why it's wrong here
Segmentation limits lateral movement after compromise but does nothing to stop the phishing email, macro execution or PowerShell payload on the initial endpoint. Segmentation is correct for containing spread from a compromised host, not for preventing the initial execution.
- ✓
Disable macros in documents originating from external sources
Why this is correct
Disabling macros in externally sourced documents breaks the attack chain at execution: the phishing email's malicious macro cannot run, so the PowerShell commands never launch. This directly addresses the root cause that bypassed the email filter.
- ✗
Deploy additional antivirus software on endpoints
Why it's wrong here
Endpoint antivirus targets known malware signatures and cannot reliably block macro-generated PowerShell abuse that already evaded the mail filter. It is tempting because antivirus is a standard endpoint control, yet it would be correct against file-borne malware rather than filter-bypassing phishing with living-off-the-land execution.
- ✗
Conduct security awareness training for all employees
Why it's wrong here
Training reduces the likelihood of users enabling macros but cannot stop a macro that already bypassed the filter from executing PowerShell. Awareness training is the right control for broad phishing susceptibility, not for blocking a specific execution technique already reaching endpoints.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.