In my previous blog posts, Azure’s Weakest Link? and Azure’s Weakest Link - Full Cross-Tenant Compromise, I gave an overview of the severely insecure architecture behind API Connections in Azure, a part of Azure Logic Apps, and an instance of a full cross-tenant compromise using these inherent flaws. Now I am back with some more vulnerabilities in this system, each giving the same primitives to the attacker. In total, the vulnerabilities here netted me a cool $200,000.
I also held a talk detailing this at Blue Hat Asia 2026, and when the recordings are out, I will add a link here.
API Connections allow anyone to fully compromise any other connection worldwide, giving full access to the connected backend. This includes cross-tenant compromise of Key Vaults and Azure SQL databases, as well as any other externally connected service, such as Jira or Salesforce. The only thing stopping exploitation is really the layers of input validation bolted onto the various systems, but as you will see, it is really difficult to catch all the edge cases here.
