The answer is to create a VPC Traffic Mirroring session targeting the instance’s ENI and mirror the traffic to a Network Load Balancer for capture. This is correct because VPC Traffic Mirroring copies all network packets at the Elastic Network Interface level without any agent, configuration change, or performance impact on the EC2 instance itself, making it ideal for full packet capture during a forensic investigation. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding of passive, agentless monitoring versus active tools like tcpdump or agent-based packet capture, which would alter the instance’s state. A common trap is choosing to install packet-capture software on the instance, which violates the “without affecting the instance” constraint. Memory tip: “Mirror means no touch” — Traffic Mirroring is a read-only copy, so the instance stays untouched for forensic integrity.
SCS-C02 Threat Detection and Incident Response Practice Question
This SCS-C02 practice question tests your understanding of threat detection and incident response. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
During a security incident, a security engineer needs to capture network traffic between an EC2 instance and an attacker's IP address for forensic analysis. The engineer has already identified the attacker's IP from CloudTrail logs. Which action captures the traffic without affecting the instance?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create a VPC Traffic Mirroring session targeting the instance's ENI and mirror the traffic to a Network Load Balancer for capture.
Option D is correct because VPC Traffic Mirroring captures all network traffic at the Elastic Network Interface (ENI) level without any performance impact or configuration change on the EC2 instance itself. It copies the traffic to a Network Load Balancer (NLB) or another target for capture and analysis, making it ideal for forensic investigation without disrupting the running instance.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Update the network ACL to log all traffic to and from the attacker's IP.
Why it's wrong here
ACLs log only allow/deny actions, not full traffic.
✗
Enable VPC Flow Logs on the subnet and query logs for the attacker's IP.
Why it's wrong here
Flow logs do not capture payload.
✗
SSH into the instance and run tcpdump with a filter for the attacker's IP.
Why it's wrong here
Alters the instance and may alert the attacker.
✓
Create a VPC Traffic Mirroring session targeting the instance's ENI and mirror the traffic to a Network Load Balancer for capture.
Why this is correct
Captures traffic without affecting the instance.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse VPC Flow Logs (which only provide metadata) with full packet capture capabilities, or they assume that SSHing into the instance is acceptable despite the risk of altering the instance state during an active incident.
Detailed technical explanation
How to think about this question
VPC Traffic Mirroring uses a mirror filter to select traffic by IP, port, or protocol, then forwards a copy of the packets to a target (e.g., an NLB or another ENI) using VXLAN encapsulation (UDP port 4789). This allows the security engineer to capture full packet contents, including application-layer data, without any agent or modification on the source instance, preserving the integrity of the forensic evidence.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Threat Detection and Incident Response — This question tests Threat Detection and Incident Response — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create a VPC Traffic Mirroring session targeting the instance's ENI and mirror the traffic to a Network Load Balancer for capture. — Option D is correct because VPC Traffic Mirroring captures all network traffic at the Elastic Network Interface (ENI) level without any performance impact or configuration change on the EC2 instance itself. It copies the traffic to a Network Load Balancer (NLB) or another target for capture and analysis, making it ideal for forensic investigation without disrupting the running instance.
What should I do if I get this SCS-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. During a security incident, a security engineer needs to capture network traffic from an EC2 instance for forensic analysis. The instance is part of an Auto Scaling group and may be terminated. What is the MOST efficient way to capture the traffic without affecting the instance's performance?
hard
✓ A.Use VPC Traffic Mirroring to mirror the instance's network traffic.
B.Enable VPC Flow Logs for the subnet.
C.SSH into the instance and run tcpdump to capture packets.
D.Attach a Network Load Balancer in front of the instance.
Why A: VPC Traffic Mirroring allows you to copy network traffic from an EC2 instance to a monitoring appliance without impacting the instance. Option A (tcpdump) is intrusive. Option B (VPC Flow Logs) captures metadata, not full packets. Option D (Network Load Balancer) forwards traffic but is not designed for forensic capture.
Last reviewed: Jun 24, 2026
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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.
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