Implementing Defense-in-Depth Authorization for MCP Tools on Amazon Quick

Enhanced Authorization for MCP Tools

A new defense-in-depth authorization pattern has been implemented for Model Context Protocol (MCP) tools on Amazon Quick. This pattern introduces granular control at the tool and parameter level for each MCP tool invocation, supplementing existing token validation. The goal is to prevent a single misconfigured permission from bypassing access requirements, which is crucial for compliance.

Multi-Gate Authorization Pattern

The implemented pattern utilizes a multi-gate authorization process that sequentially evaluates OpenID Connect (OIDC) JSON Web Token (JWT) claims. This allows for the enforcement of both role-based and attribute-based access control on every tool invocation. Organizations can configure which authorization controls to activate based on their specific compliance needs, ranging from group-based permissions to parameter-level attribute checks. Microsoft Entra ID is used as the identity provider in the provided example.

Addressing Authorization Gaps

While single sign-on (SSO) confirms a caller's identity when connecting MCP tools to Amazon Quick, it does not define what actions they are authorized to perform. Authorization bridges this gap by translating a verified identity into a set of enforceable rules. Without layered authorization, an overly broad token could grant access to tools and data beyond a caller’s designated role, potentially exposing sensitive data and complicating compliance audits. MCP is an open protocol designed to connect applications to internal tools, databases, and APIs.

Beyond Authentication

When sensitive data sources are connected to Amazon Quick via MCP, simple authentication is insufficient for authorization. The authorization layer determines which tools a caller can invoke, from what locations, and at what privilege level. For instance, a regulated organization might require multi-factor authentication (MFA) at sign-in and restrict access from unapproved countries. The identity provider handles MFA, while the authorization layer enforces geographic restrictions. Standard OAuth 2.0 identity verification does not enforce controls at the tool and parameter level.

How the Pattern Works

The multi-gate authorization pattern processes OIDC JWT claims through four distinct gates: MFA, geographic restriction, group-to-role mapping, and tool-level access. This layered approach ensures comprehensive access control for MCP tools.