Security Token Service (STS)

In AWS, STS stands for Security Token Service. It's a web service that enables you to request temporary, limited-privilege credentials for IAM (Identity and Access Management) users or federated users. STS helps you to control access to your AWS resources by issuing temporary security credentials that are valid for a specific period and have limited permissions.

STS supports different use cases such as cross-account access, federated access to AWS resources, and providing temporary credentials for applications running on EC2 instances. It's a crucial component for implementing secure access control mechanisms in AWS environments.