CS0-003 Incident Response and Management Practice Question
After containing a ransomware incident, the incident response team is conducting post-incident activities. Which action is MOST important to prevent a similar attack in the future?
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
✓
Performing a root cause analysis and implementing remediation
Conducting a root cause analysis identifies the underlying vulnerability or weakness that allowed the attack, enabling targeted remediation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Sharing IOCs with other organizations via a threat intelligence platform
Why it's wrong here
While sharing Indicators of Compromise (IOCs) via platforms like TAXII or MISP is a valuable community practice during the post-incident phase, it does not secure the local environment. This outward-facing action does nothing to identify or close the specific vulnerability that allowed the ransomware to execute initially. Consequently, the organization remains vulnerable to the exact same attack vector.
- ✗
Reimaging all affected systems
Why it's wrong here
Reimaging infected hosts successfully eradicates active malware payloads and restores systems to a known good state. However, this action is merely a containment and eradication step that fails to address the underlying security gap, such as an unpatched vulnerability or misconfigured service. Without identifying how the threat actor gained entry, redeployed systems will remain exposed to reinfection.
- ✓
Performing a root cause analysis and implementing remediation
Why this is correct
Performing a root cause analysis (RCA) allows the incident response team to trace the attack path back to the initial point of entry and understand the vulnerabilities exploited. Implementing targeted remediation based on these findings—such as patching software, disabling unnecessary protocols, or enforcing multi-factor authentication—directly eliminates the security gaps. This is the only action that systematically prevents the same threat actor or campaign from recurring.
- ✗
Updating the incident response plan
Why it's wrong here
Updating the incident response (IR) plan is a key activity during the lessons learned phase to improve future operational readiness and coordination. However, modifying policy documentation does not implement technical controls or fix the active vulnerabilities that led to the breach. To prevent immediate reinfection, technical remediation of the compromised infrastructure must take precedence over administrative document updates.
Go deeper
Related to this question
Learn chapter
NIST Incident Response Framework
Key term
Remediation
Remediation is the process of fixing or eliminating vulnerabilities, misconfigurations, or security weaknesses in an IT environment.
Key term
Analysis
In incident response, analysis is the process of examining data and events to determine what happened, how it happened, and what actions to take.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CS0-004 practice question is part of Courseiva's free CompTIA 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 CS0-004 exam.