Azure Application Proxy C2

### Executive Summary This report provides a step-by-step technical walkthrough and proof-of-concept for abusing Azure AD Application Proxy (which leverages Azure Service Bus) to create an inbound, certificate-authenticated C2 tunnel into an environment. It covers creating OAuth tokens and a client certificate, generating a CSR, interacting with the registration endpoint, establishing Service Bus-based WebSocket signaling channels, retrieving request payloads, and returning responses—demonstrating a stealthy technique that could be used by red teams or threat actors to tunnel C2 traffic through commonly trusted cloud infrastructure.