Amazon Kinesis and Amazon Elasticsearch are both suitable for forensic-logging solutions. Amazon Kinesis can collect, process, and analyze streaming data in real time3. Amazon Elasticsearch can store, search, and analyze log data using the popular open-source tool Elasticsearch. The other options are not designed for forensic-logging purposes. Amazon Athena is a query service that can analyze data in S3, Amazon SQS is a message queue service that can decouple and scale microservices, and AmazonEMR is a big data platform that can run Apache Spark and Hadoop clusters.

Understand the Problem:

The inability of external users to log in indicates potential issues with configuration or permissions.

Review Cognito Configuration:

Check for recent changes in Cognito user pool settings, such as password policies or authentication flow configurations.

Ensure the app client settings (e.g., callback URLs, OAuth flows) are correctly configured.

Review IAM Policies and Role Trust Relationships:

Verify that IAM roles used by Cognito (e.g., for identity providers) have the correct policies attached.

Ensure trust relationships for roles are properly configured to allow Cognito to assume them.

Advantages of Reviewing Configurations:

Addresses the root cause of login failures without disrupting user experience (e.g., resetting passwords).

Next Steps:

If no issues are found in the configuration, proceed with detailed logging and monitoring using CloudTrail (Option A).

Troubleshooting Amazon Cognito User Pools

Configuring App Clients in Cognito

IAM Roles for Cognito

The correct answer is C. The GuardDuty integration with Security Hub was never activated in the AWS account where the finding was generated.

The reason is that Security Hub does not automatically receive findings from GuardDuty unless the integration is activated in each AWS account.According to the AWS documentation1, “The Amazon GuardDuty integration with Security Hub enables you to send findings from GuardDuty to Security Hub. Security Hub can then include those findings in its analysis of your security posture.” However, this integration is not enabled by default and requires manual activation in each AWS account.The documentation1also states that “You must activate the integration in each AWS account that you want to send findings from GuardDuty to Security Hub.”

Therefore, even though the company has configured the security tooling account as the delegated administrator for GuardDuty and Security Hub, and has enabled these services for existing and new AWS accounts, it still needs to activate the GuardDuty integration with Security Hub in each account. Otherwise, the findings from GuardDuty will not be sent to Security Hub and will not be visible in the delegated administrator account.

The other options are incorrect because:

A. VPC flow logs are not required for GuardDuty to generate DNS findings. GuardDuty uses VPC flow logs as one of the data sources for network connection findings, but not for DNS findings.According to the AWS documentation2, “GuardDuty uses VPC Flow Logs as a data source for network connection findings.”

B. The VPC DHCP option configured for a custom OpenDNS resolver does not affect GuardDuty’s ability to generate DNS findings. GuardDuty uses DNS logs as one of the data sources for DNS findings, regardless of the DNS resolver used by the VPC.According to the AWS documentation2, “GuardDuty uses DNS logs as a data source for DNS activity findings.”

D. Cross-Region aggregation in Security Hub is not relevant for this scenario, since the company operates out of a single AWS Region. Cross-Region aggregation in Security Hub allows you to aggregate security findings from multiple Regions into a single Region, where you can view and manage them. However, this feature is not needed if the company only uses one Region.According to the AWS documentation3, “Cross-Region aggregation enables you to aggregate security findings from multiple Regions into a single Region.”