hardMultiple Choice
CISM Practice Question: A large enterprise experiences a data breach…
A large enterprise experiences a data breach involving personal identifiable information (PII) of customers. The incident response team has contained the breach and is now in the eradication phase. The CISO wants to ensure that the same vulnerability cannot be exploited again. Which action is MOST critical?
⚠ Common exam trap
ISACA often tests the distinction between containment actions (like password resets) and eradication actions (like patching), tricking candidates into choosing a visible, immediate step over the root-cause fix.
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
✓
Patch the specific vulnerability identified.
Patching the specific vulnerability is the most critical action during the eradication phase because it permanently removes the root cause of the breach. Without this step, the same attack vector (e.g., an unpatched SQL injection flaw or a known CVE in a web server) remains exploitable, rendering containment efforts temporary. The CISO's goal to prevent recurrence directly requires eliminating the technical weakness, not just mitigating its symptoms.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Change all passwords of affected accounts.
Why it's wrong here
Resetting passwords only invalidates existing credentials; it does not close the vulnerability that permitted the intrusion, so the same flaw remains exploitable. It is tempting because credential rotation is a familiar containment follow-up, and would be correct when compromised accounts, not an unpatched weakness, are the exposure.
- ✗
Notify affected customers about the breach.
Why it's wrong here
Customer notification is a legal and communications obligation, not a technical remediation, and does nothing to prevent re-exploitation. It tempts because breach notification is mandatory under privacy regulations, making it correct during the reporting phase rather than eradication.
- ✗
Deploy additional endpoint protection software.
Why it's wrong here
Adding endpoint protection does not confirm the specific exploited vulnerability is closed, and may not cover the affected vector. It tempts because layered endpoint defences are a legitimate hardening measure, but eradication requires targeted patching or reconfiguration of the actual root cause.
- ✓
Patch the specific vulnerability identified.
Why this is correct
Patching removes the exploited flaw at its source, so the same vulnerability cannot be reused against the organisation. Containment and eradication alone leave the underlying weakness present, meaning a repeat breach remains possible. Applying the vendor fix directly satisfies the CISO's requirement that the vulnerability be permanently closed.
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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.