Amazon STS now supports cross-partition federation for Amazon identities
Amazon Security Token Service (Amazon STS) now lets your workloads use their Amazon Identity and Access Management (IAM) identity in one partition to get temporary credentials for an IAM role in a different partition, without storing long-term credentials, which can help improve your security posture. Partitions are groups of Amazon Web Services Regions, such as the Amazon Web Services China Regions, and each partition has an independent instance of IAM, creating a hard boundary between them. Previously, organizations that run workloads across partitions commonly relied on long-term credentials, such as IAM user access keys, that don't expire automatically.
With this launch, your workload requests a short-lived token from Amazon STS in its own partition and exchanges it for temporary credentials in the other partition, using the existing GetWebIdentityToken and AssumeRoleWithWebIdentity APIs. You control which identities can access each role, apply governance across your organization, and audit token use in Amazon CloudTrail in both partitions. This launch helps with scenarios such as consolidated security and compliance reporting, and centralized operations tooling. If your organization already operates a public key infrastructure (PKI), IAM Roles Anywhere is another option for cross-partition access.
Cross-partition federation is available at no additional charge in the Amazon Web Services China (Beijing) Region, operated by Sinnet, and the Amazon Web Services China (Ningxia) Region, operated by NWCD. To learn more, see Federating Amazon identities across Amazon partitions in the IAM User Guide.