What should IAM teams do before allowing Bedrock across accounts?

Set the trust boundary before Bedrock can be used across accounts

Before you allow cross-account invocation, IAM teams should define the exact trust boundary: which accounts may call Bedrock, which regions are allowed, and which principals are permitted to invoke models. That prevents “any trusted AWS principal” from becoming the default and keeps the sharing model narrow enough to audit.

The practical test is whether you can explain every permitted path as a named business or platform relationship, not as an implicit network reachability decision. If the trust boundary is vague, cross-account access will grow faster than governance and the approval model will become impossible to defend later.

Cloud Workload Identity Guide is useful here because it shows how temporary, federated, and role-based access models keep cross-environment usage tied to explicit identity rather than static keys.

Cloud PAM and CIEM Guide also fits this decision point because cross-account Bedrock access should be treated as a privilege path that needs right-sizing before production rollout.

Require every invocation to resolve to an authoritative identity

Bedrock sharing should not be approved if the platform can only tell you that “an AWS account” made the request. Each call needs to map back to a traceable principal, role, or workload identity so the consumer is attributable at review time and during incident response.

That identity mapping should survive delegation and automation. If a CI pipeline, workload role, or application proxy calls Bedrock on behalf of a user or service, the logging and access design must preserve both the direct caller and the business owner of the action.

Ultimate Guide to NHIs, What are Non-Human Identities supports this because Bedrock consumers are often workloads or services, not just human admins.

Lifecycle Processes for Managing NHIs is relevant too, since the identity behind a Bedrock integration must be provisioned, reviewed, and retired like any other privileged access path.

Active Directory and Entra ID Hardening Guide is a useful adjacent reference when the Bedrock consumer is governed through enterprise identity controls and privileged role assignment.

Make sharing auditable by design, not by exception

Cross-account model access is only safe when the approval model is narrow enough to review and the evidence chain is strong enough to reconstruct after the fact. That means logging the invoking principal, source account, target account, region, and model usage context, then reviewing those records as part of normal access governance.

It also means treating region scope as a control, not a preference. If teams can invoke models in multiple regions without an explicit reason, you increase the chance of data residency drift, compliance blind spots, and inconsistent retention or monitoring behavior across environments.

Regulatory and Audit Perspectives helps frame why traceability and access review matter when shared access crosses organizational boundaries.

CSA Cloud Controls Matrix is a strong external control reference for IAM, audit, and cloud governance expectations around shared access.

Practitioner Guidance

What to prioritize: approve only the smallest set of source accounts, regions, and principals that can be tied to an owned workload or role. If a proposed Bedrock path cannot be traced to a clear owner and business purpose, it is not ready for cross-account use.

What to verify: confirm that the permission model, logging, and review process can show who invoked the model, from where, under which role, and for what environment. If any of those fields are missing, the control is not auditable enough for production.

Common mistake: teams often validate the AWS trust relationship but skip the governance question of whether the caller should be allowed to invoke that model at all, in that region, for that data set. That shortcut turns cross-account sharing into an implicit trust expansion.

Practitioner takeaway: treat Bedrock cross-account enablement as an identity and authorization decision first, and a platform integration second. If you cannot attribute every invocation to an authoritative identity and a named trust boundary, the sharing model is too loose to approve.

Related resources from NHI Mgmt Group

• How should security teams govern non-human identities alongside human accounts?
• How should security teams make NHI best practices usable across the business?
• How should security teams govern Active Directory service accounts?
• How should IAM teams handle employees who have multiple accounts across systems?