SCS-C02 Threat Detection and Incident Response Practice Question
During a security incident, a security engineer needs to preserve forensic evidence from an EC2 instance that may be compromised. The instance is running a critical application. Which approach minimizes data loss while ensuring the integrity of the evidence?
⚠ Common exam trap
Many exam-takers think terminating the instance is the safest way to stop malicious activity, but they overlook the irreversible loss of forensic evidence and the need to preserve the disk state for investigation.
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
✓
Create an EBS snapshot, then isolate the instance by modifying the security group and removing it from the load balancer.
Creating an EBS snapshot preserves the disk state at the point of the incident, capturing forensic evidence without altering the running instance. Isolating the instance by modifying the security group (e.g., removing all inbound/outbound rules) and removing it from the load balancer stops network traffic and prevents further compromise, minimizing data loss while maintaining the integrity of the evidence for later analysis.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Create an EBS snapshot, then isolate the instance by modifying the security group and removing it from the load balancer.
Why this is correct
Taking an EBS snapshot first preserves the root and data volumes as a point-in-time forensic copy of the disk, while leaving the instance running so volatile state is not yet lost. Then you isolate the instance by swapping its security group to a deny-all rule set and deregistering it from the load balancer, which cuts all network paths without modifying the guest OS or killing processes. This containment step prevents lateral movement and further data exfiltration while preserving the ability to later analyze memory, network connections, and disk state.
- ✗
Immediately terminate the instance to stop any ongoing malicious activity.
Why it's wrong here
Immediately terminating the instance is a destroy-in-place action that permanently discards volatile data such as memory contents, open file handles, active network connections, and any ephemeral instance-store volumes, as well as clearing kernel-level evidence. Even if delete-on-termination is disabled for the EBS volume, the crash-dump and process state are gone, and the forensic chain of custody is broken because the runtime evidence no longer exists. This may also trigger Auto Scaling to launch a replacement host, potentially destroying the original’s placement data and making attribution harder.
- ✗
SSH into the instance and run forensic tools to capture memory.
Why it's wrong here
SSHing into the instance to run forensic tools alters the very evidence you intend to collect: the login writes to /var/log/wtmp and lastlog, updates shell history and atime, injects new processes into the process table, and modifies memory, so a defensible forensic timeline is contaminated. Interactive sessions can also trip EDR or shell monitoring, alerting an active attacker who may then accelerate destroying logs or move laterally. Even if you use a static binary, the act of connecting over SSH and executing commands is not an acquisition technique that preserves the original state.
- ✗
Detach the instance from the Auto Scaling group and leave it running without changes.
Why it's wrong here
Detaching the instance from the Auto Scaling group only prevents scaling actions from managing its lifecycle; it does nothing to interrupt the attacker’s active network sessions or stop ongoing write/delete operations on the compromised host. Leaving the instance fully connected to the VPC and its existing security group allows the attacker to continue exfiltrating sensitive data, pivoting to other resources, or planting backdoors, and any resulting writes can overwrite forensic evidence. The correct move is network-level isolation, not just lifecycle detachment.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SCS-C02 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-C02 exam.