Azure API Flaws Enable Cross-Tenant Compromise

A researcher netted $200,000 from vulnerabilities found in the Azure API Connections system, details of which were presented at Blue Hat Asia 2026. The flaws allow anyone to fully compromise any other connection worldwide, enabling cross-tenant compromise of Key Vaults and Azure SQL databases. Access to externally connected services such as Jira or Salesforce is also possible through these vulnerabilities.

The author identified four undocumented functions, including DynamicInvoke and DynamicList, within Standard Logic App code. Using the DynamicList endpoint, the researcher achieved a cross-tenant write on a victim's SQL server. Microsoft initially marked the DynamicInvoke vulnerability as fixed a couple of weeks after it was reported, but their fix involved blocking all dynamic endpoints rather than just addressing DynamicInvoke.

Further analysis revealed that Consumption Logic Apps have implicit access to every Version 1 API Connection. The author exploited the host.api.RuntimeUrl parameter to bypass input validation by specifying a runtime URL ending with azure-apihub.net. The author found that the fix checks the value at the wrong time, allowing the exploit to work again.