Entra Agent ID: Inside a cross-tenant agent compromise

This report demonstrates a cross-tenant takeover where an attacker with Agent ID Administrator access in a corporate Entra tenant adds a credential to a third-party 'People Team Agents' blueprint, uses that credential to authenticate the blueprint principal in a subsidiary tenant, enumerates and impersonates an agent identity (Temporary Access Agent) via token exchange, and abuses its Microsoft Graph permissions to create a Temporary Access Pass for a Global Administrator account, achieving full tenant compromise; the post highlights risks of trusting third-party blueprints and the need to secure agent identities.