Microsoft Incident Response – Detection and Response Team (DART) researchers uncovered a new backdoor that is notable for its novel use of the OpenAI Assistants Application Programming Interface (API) as a mechanism for command-and-control (C2) communications. Instead of relying on more traditional methods, the threat actor behind this backdoor abuses OpenAI as a C2 channel as a way to stealthily communicate and orchestrate malicious activities within the compromised environment. To do this, a component of the backdoor uses the OpenAI Assistants API as a storage or relay mechanism to fetch commands and run tasks for the threat actor.