CCSP Cloud Security Operations Practice Question
A security analyst is investigating a potential compromise of an AWS EC2 instance. Which step should be taken FIRST to contain the incident and prevent further damage?
⚠ Common exam trap
A common misconception is that immediate termination (Option A) is the fastest containment method, but this violates the principle of preserving evidence and may hinder forensic 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
✓
Isolate the EC2 instance by updating the security group to deny all traffic.
The first priority in incident response is containment. Updating the security group to deny all traffic immediately isolates the EC2 instance from network communication, preventing lateral movement or data exfiltration while preserving the instance for further investigation. This aligns with the NIST SP 800-61 incident response framework, which emphasizes containment before eradication or recovery.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Terminate the EC2 instance immediately.
Why it's wrong here
Terminating the instance destroys volatile memory and disk state, erasing forensic evidence needed to identify the compromise vector. It is tempting as a blunt containment measure, and would be correct only when an instance is actively propagating attacks and evidence preservation is not required.
- ✗
Take a snapshot of the instance for forensic analysis.
Why it's wrong here
Snapshotting preserves volatile evidence but leaves the compromised instance running, so an attacker retains access and can cause further damage. It is tempting because snapshots are the correct forensic preservation step once containment is achieved, but containment must precede evidence capture.
- ✓
Isolate the EC2 instance by updating the security group to deny all traffic.
Why this is correct
Replacing the instance's security group with one denying all inbound and outbound traffic cuts attacker access instantly while leaving the instance running. Memory, processes and disk state remain intact for forensic capture, unlike termination or reboot, which would destroy volatile evidence.
- ✗
Disable the IAM role attached to the instance.
Why it's wrong here
Disabling the attached IAM role removes the instance's AWS API permissions, but the compromised operating system and its network access remain active, so the attacker can still operate. It is tempting because revoking credentials limits cloud-side abuse, yet isolation of the instance itself is required first.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CCSP practice question is part of Courseiva's free ISC2 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 CCSP exam.