SCS-C02 Threat Detection and Incident Response Practice Test 14 — 15 Questions

Question 1

During an incident, a security engineer needs to isolate a compromised Amazon EC2 instance without losing the ability to capture forensic data from its EBS volumes. What is the best course of action?

Accepted Answer

Take a snapshot of the EBS volumes, then detach the instance from the Auto Scaling group and modify the security group to deny all traffic.. Taking a snapshot of the EBS volumes preserves the forensic data before any changes occur, while detaching the instance from the Auto Scaling group prevents automatic replacement, and modifying the security group to deny all traffic isolates the instance without losing the running state or the ability to capture additional volatile data. This approach balances isolation with forensic preservation, ensuring the instance remains available for further analysis if needed.

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Terminate the instance immediately and take a snapshot after termination.

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Stop the instance, detach the volumes, and attach them to a forensic instance.

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Change the security group to restrict traffic to only the forensic team's IP addresses.

Question 2

A company is using AWS WAF to protect a web application. The security team wants to receive alerts when a specific rule block is triggered. Which AWS service should they use to achieve this?

Accepted Answer

CloudWatch Alarms with SNS. AWS WAF integrates with Amazon CloudWatch to provide metrics for each rule, including the 'BlockedRequests' count. By creating a CloudWatch Alarm on this metric, you can trigger an SNS notification when the threshold is exceeded, alerting the security team. This is the standard pattern for receiving alerts on WAF rule actions, as CloudWatch Alarms with SNS provide the necessary monitoring and notification pipeline.

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Amazon EventBridge

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Amazon S3

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Amazon SNS

Question 3

An organization uses AWS Organizations with hundreds of accounts. The security team wants to automatically respond to a specific GuardDuty finding by isolating the affected EC2 instance. What is the recommended architecture?

Accepted Answer

Use EventBridge to trigger a Lambda function in the delegated administrator account, which assumes an IAM role in the affected account to isolate the instance.. It follows the recommended architecture for cross-account automated response to GuardDuty findings. EventBridge in the delegated administrator account captures the finding and triggers a Lambda function, which then assumes an IAM role (using STS AssumeRole) in the affected member account to perform the isolation. This pattern centralizes management while respecting the security boundary between accounts.

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Configure GuardDuty to invoke a Lambda function in the affected account directly.

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Use EventBridge to send the finding to a Step Functions workflow that isolates the instance.

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Use AWS Systems Manager Automation to isolate the instance across accounts.

Question 4

Which THREE actions should be taken when preserving forensic evidence from an EC2 instance during an incident? (Select THREE.)

Accepted Answer

Create an EBS snapshot of all volumes.. Creating an EBS snapshot preserves the exact state of the volume at the time of the incident, including any malicious files, logs, or artifacts. This snapshot can be used for offline forensic analysis without altering the original evidence. AWS recommends this as a first step in forensic acquisition to maintain chain of custody.

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Reboot the instance to clear any malicious processes.

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Terminate the instance to prevent further compromise.

Question 5

A security engineer needs to detect and respond to potential credential theft where an IAM user's access key is being used from an unusual geographic location. Which AWS service should be used to generate alerts based on this anomaly?

Accepted Answer

Amazon GuardDuty. Amazon GuardDuty is the correct choice because it is a threat detection service that uses machine learning and integrated threat intelligence to identify anomalous behavior, such as an IAM access key being used from an unusual geographic location. It specifically analyzes CloudTrail management and data events, VPC flow logs, and DNS logs to detect credential theft patterns like a new geolocation or an impossible travel scenario, and can trigger alerts via Amazon EventBridge or SNS for automated response.

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AWS IAM Access Analyzer

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AWS CloudTrail

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AWS Config

Question 6

A company uses AWS Organizations with multiple accounts. The security team wants a centralized view of all security alerts and findings from services like GuardDuty, Security Hub, and Inspector across all accounts. What is the MOST efficient way to achieve this?

Accepted Answer

Use AWS Security Hub with cross-account aggregation in the management account.. AWS Security Hub is designed to aggregate findings from multiple security services (GuardDuty, Inspector, etc.) across accounts. By enabling cross-account aggregation in the management account of AWS Organizations, Security Hub provides a single, centralized dashboard for all security alerts and findings without needing to collect raw logs or build custom dashboards. This is the most efficient and native approach for a multi-account environment.

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Use AWS Systems Manager OpsCenter to centrally view all security findings.

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Use individual service consoles (GuardDuty, Security Hub, Inspector) for each account.

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Use Amazon CloudWatch Logs to collect logs from each account and create custom dashboards.

Question 7

A company has enabled AWS CloudTrail and wants to receive real-time notifications when specific API calls, such as DeleteTrail, are made. Which service should be used to trigger an alert based on CloudTrail log events?

Accepted Answer

Amazon CloudWatch Events / Amazon EventBridge. Amazon CloudWatch Events (now part of Amazon EventBridge) is the correct service to trigger real-time alerts based on CloudTrail log events. You can create a rule that matches specific API calls, such as DeleteTrail, and route the event to a target like an SNS topic or Lambda function for immediate notification. CloudTrail delivers log events to CloudWatch Logs, and EventBridge can directly consume those events for pattern matching and alerting.

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AWS CloudTrail console notifications

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Amazon VPC Flow Logs

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Amazon S3 event notifications

Question 8

During a security review, a security engineer notices that an S3 bucket contains sensitive data but has a bucket policy that allows access from any principal in the account. The engineer needs to identify any unintended cross-account access to this bucket. Which AWS service should be used?

Accepted Answer

AWS IAM Access Analyzer. AWS IAM Access Analyzer helps identify resources that are shared with external principals by analyzing resource-based policies (like S3 bucket policies). In this scenario, the bucket policy allows access from any principal in the account, but IAM Access Analyzer can detect if the policy also grants access to principals outside the AWS account (cross-account access). It generates findings for any policy that allows access from an external entity, making it the correct service to identify unintended cross-account access.

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AWS Config

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AWS Trusted Advisor

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Amazon Macie

Question 9

A security engineer is investigating a potential data exfiltration from an S3 bucket that is configured to allow public access. The engineer wants to determine who accessed the bucket and from which IP addresses. Which AWS capability should be used?

Accepted Answer

AWS CloudTrail data events for S3. AWS CloudTrail data events for S3 capture detailed API activity at the object level, including GetObject, PutObject, and DeleteObject calls. This allows the security engineer to identify exactly who accessed the bucket (via the user identity) and from which IP address (via the sourceIPAddress field in the CloudTrail event). Unlike management events, data events must be explicitly enabled and provide the granularity needed for this investigation.

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Amazon S3 server access logs

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AWS IAM Access Analyzer

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Amazon VPC Flow Logs

Question 10

A company wants to ensure that all API calls made to AWS are logged for security analysis. Which TWO services can be used to achieve this? (Choose two.)

Accepted Answer

Amazon S3 server access logs. Amazon S3 server access logs capture detailed records of requests made to an S3 bucket, including the requester, bucket name, request time, and action. This enables security analysis of API calls specifically targeting S3 resources. AWS CloudTrail records all API calls made to the AWS Management Console, SDKs, and CLI across the entire AWS account, providing a comprehensive audit trail for security analysis.

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Amazon VPC Flow Logs

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Amazon CloudWatch Logs

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AWS Config

Question 11

A security engineer notices that an EC2 instance is sending outbound traffic to a known malicious IP address. The engineer needs to immediately block the traffic and capture a packet capture for forensic analysis. Which combination of actions should the engineer take?

Accepted Answer

Add a network ACL deny rule for the malicious IP, and enable VPC Traffic Mirroring.. A network ACL (NACL) is a stateless firewall that operates at the subnet level, allowing immediate blocking of traffic to/from a specific IP address without affecting the instance's security group rules. Enabling VPC Traffic Mirroring captures a full packet-level copy of the traffic for forensic analysis, which is superior to VPC Flow Logs (which only capture metadata). This combination provides both rapid containment and deep forensic data.

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Use Amazon GuardDuty to block the IP and enable VPC Traffic Mirroring.

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Stop the EC2 instance and enable VPC Flow Logs.

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Modify the security group to deny outbound traffic to the IP, and enable VPC Flow Logs.

Question 12

A security engineer is investigating a potential compromise of an EC2 instance. The engineer wants to capture memory and disk forensics without shutting down the instance. Which service should the engineer use?

Accepted Answer

AWS Systems Manager. AWS Systems Manager (SSM) is the correct service because it provides the capability to perform forensic data collection on a running EC2 instance without shutting it down. Specifically, SSM Automation documents like AWS-RunShellScript or AWS-GatherEC2InstanceInfo can execute commands to capture memory (e.g., using LiME or fmem) and disk forensics (e.g., dd or volume snapshots) via the SSM Agent, which runs as a system service and does not require instance termination.

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AWS Config

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EC2 Instance Connect

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Amazon CloudWatch Logs

Question 13

A security engineer is designing an incident response plan for a containerized application running on Amazon ECS with Fargate. The engineer needs to ensure that if a container is compromised, the incident response team can capture a memory dump and disk snapshot for forensic analysis. The containers are stateless and use ephemeral storage. Which approach provides the necessary forensic data?

Accepted Answer

Use ECS Exec to access the container and capture a memory dump; snapshot the task's ephemeral storage.. ECS Exec allows interactive access to a running container without stopping it, enabling the capture of a memory dump (e.g., via `gcore` or `/proc/kcore`). Additionally, the task's ephemeral storage can be snapshotted while the container is still running, preserving disk state for forensic analysis. This approach aligns with incident response best practices for stateless containers on Fargate, where traditional host-level forensics are unavailable.

Answer

Configure the container to stream /dev/mem to CloudWatch Logs.

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Enable ECS task memory dumps to CloudWatch Logs.

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Stop the task and create a new task from the same image.

Question 14

A security engineer notices that an EC2 instance is sending outbound traffic to a known malicious IP address. The instance is part of an Auto Scaling group behind an Application Load Balancer. The engineer needs to immediately stop the exfiltration while preserving forensic evidence. What is the BEST course of action?

Accepted Answer

Remove the instance from the target group and apply a security group that denies all traffic.. Removing the instance from the target group immediately stops new traffic from the Application Load Balancer to the instance, while applying a security group that denies all outbound traffic (e.g., a custom security group with no outbound rules) halts any ongoing exfiltration without destroying the instance or its attached EBS volumes. This preserves the forensic evidence (memory, disk, logs) for later analysis, unlike termination or shutdown which could lose volatile data.

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Detach the EBS volume from the instance.

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Terminate the EC2 instance immediately.

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Shut down the instance from within the OS.

Question 15

A security analyst needs to detect and alert on suspicious API calls in real time. Which combination of AWS services should be used?

Accepted Answer

AWS CloudTrail, Amazon CloudWatch Logs, and Amazon EventBridge.. AWS CloudTrail captures API calls and delivers log files to Amazon CloudWatch Logs, where you can define metric filters to detect suspicious patterns. Amazon EventBridge then consumes those filtered log events to trigger real-time alerts or automated remediation actions. This combination provides the end-to-end pipeline needed for real-time detection and alerting on API activity.

Answer

Amazon Inspector and AWS CloudTrail.

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Amazon GuardDuty and AWS Lambda.

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AWS Config and Amazon SNS.