SCS-C03 Incident Response Practice Question
An organization's security team detects an active data exfiltration event originating from a compromised Amazon EC2 Linux instance. The instance contains critical forensic evidence that must be preserved. What is the most effective immediate containment action that prevents external communication while retaining the memory state for forensic analysis?
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
✓
Modify the security groups attached to the EC2 instance to block all inbound and outbound traffic while keeping the operating system running.
Isolating the compromised instance using a dedicated security group ensures complete network containment while preventing any state loss. Stopping or terminating the instance would wipe volatile RAM memory, permanently destroying crucial artifacts required for deep forensic investigation. Preserving memory is critical for identifying intrusion vectors and achieving root cause analysis compliance during major security incidents.
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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Stop the EC2 instance immediately to disconnect it from the network and preserve the attached Amazon EBS root volume for offline examination.
Why it's wrong here
Stopping an instance causes the underlying hypervisor to release host resources and flushes volatile memory contents. This destructive action permanently destroys ephemeral RAM artifacts, rendering memory forensics impossible and violating standard incident response containment chains of custody.
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Terminate the compromised instance and launch a replacement instance from a clean AMI to maintain high availability and service uptime.
Why it's wrong here
Terminating the resource destroys all evidence permanently, eliminating logs, active network connections, and volatile memory states. This aggressive action prevents root cause analysis and fails to preserve the forensic integrity needed for legal or compliance investigations.
- ✓
Modify the security groups attached to the EC2 instance to block all inbound and outbound traffic while keeping the operating system running.
Why this is correct
Applying a restrictive security group containing explicit deny rules or zero allowable traffic isolates the instance instantly. Keeping the instance powered on maintains the volatile memory state, allowing forensic specialists to capture RAM dumps safely before shutdown.
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Detach the primary Amazon EBS volume from the running instance and attach it to an isolated analysis instance for live scanning.
Why it's wrong here
Detaching an active root volume from a running instance can cause file system corruption due to unwritten cache blocks. Furthermore, this method fails to capture volatile RAM data and disrupts active network connections abruptly without proper containment controls.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
This SCS-C03 practice question is part of Courseiva's free Amazon Web Services 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 SCS-C03 exam.