OAuth Token Exchange

Overview

OAuth Token Exchange is an OAuth protocol for requesting a new security token based on another token, including delegation and impersonation scenarios. It is not a simple refresh-token operation because the subject, actor, audience, resource, scope, and token type can change across the exchange.

The principal risks include privilege escalation, token laundering, confused-deputy behavior, cross-tenant exchange, actor context being lost, unrestricted audiences, and long chains that are difficult to audit. A compromise response for OAuth Token Exchange should support rapid revocation, replacement, affected-client identification, and review of prior use.

A production implementation should validate subject and actor tokens, constrain allowed exchange paths, enforce audience and resource policy, preserve delegation context, minimize scope, and log the resulting trust chain. Monitoring for OAuth Token Exchange should track failed use, unusual scope or audience, expiry, rotation status, and attempts involving revoked credentials.

Useful measures include exchange success and denial rates, scopes expanded or reduced, actor-token usage, exchange-chain depth, invalid audiences, and anomalous cross-service exchanges. OAuth Token Exchange is closely connected to OAuth 2.0, Integration Credential, and Authorization Header. For OAuth Token Exchange, secrets and tokens should remain outside browser bundles, URLs, ordinary logs, and unprotected configuration.

Evidence for OAuth Token Exchange should record the credential or certificate identifier and decision result without retaining the secret itself.

The OAuth Token Exchange recovery process should restore access without bypassing the original identity and authorization controls. Least-privilege configuration for OAuth Token Exchange should be verified against the operations used by each environment and consuming service.