Fine-grained access control solution for Bedrock knowledge base tools

In an official blog post, AWS introduces a fine-grained access control solution for Amazon Bedrock Managed Knowledge Base tools, addressing the privilege escalation risk that can arise when the large model itself decides userContext during agent calls to the search tool. The solution uses a request interceptor at the AgentCore Gateway tool layer to inject userContext from a verified JWT, and then the Managed Knowledge Base's ACL awareness filters documents according to user permissions. The solution requires an AWS account and IAM permissions to create the relevant resources. If applied to an existing Amazon Cognito user pool, the user pool must be on the Essentials or Plus feature plan, because access token customization requires that plan; on a Lite plan user pool, access tokens do not contain an email claim, and the interceptor and the Policy in AgentCore will reject all tool calls. After testing is complete, the stack should be deleted to avoid subsequent charges.

AI overview based on source reports · Updated 2 days ago