“The resulting list of resources contained hundreds and hundreds of resources belonging to other customers.”
Azure Health Bot lets healthcare providers point patient-facing chatbots at outside data sources. Tenable’s server answered with a redirect, and Microsoft’s filter on the internal metadata service let it straight through. The token that came back listed other customers’ resources in a service built around patient data. Microsoft’s fix was to reject redirects, and the FHIR validation endpoint had the same hole.