A company is planning to migrate its applications to AWS in a single AWS Region.

Amazon GuardDuty provides intelligent threat detection and continuous monitoring for malicious or unauthorized behavior to protect AWS accounts and workloads. It satisfies the requirement for monitoring endpoints for anomalous network traffic.

AWS Certificate Manager (ACM) simplifies the process of provisioning, managing, and deploying SSL/TLS certificates. Configuring ELB with ACM ensures encryption in transit.

AWS KMS with S3 bucket policy using x-amz-server-side-encryption ensures that S3 objects are encrypted at rest using managed keys. Denying uploads that do not use SSE with a bucket policy enforces encryption at rest.

These three actions together satisfy the stated security requirements with minimal operational overhead.