CLOSEDQUORUM Malware Uses Commercial LLM Quorum for Autonomous C2

Cisco Talos reported CLOSEDQUORUM, a 64-bit Go-based Windows implant that delegates tactical command-and-control decisions to a plurality vote among commercial LLMs including DeepSeek, Qwen, Mistral, and Google Gemini. Rather than depending on a conventional attacker-controlled C2 server or continuous operator input, the malware can use the models' structured responses to select actions such as credential theft, persistence, and process injection—including techniques that can execute malicious code within legitimate processes and evade process-based defenses.

The observed sample was an inert template containing placeholder API keys and a dummy Discord webhook, so Talos could not validate end-to-end execution or deployment in the wild. Build artifacts suggest customized variants may embed provider credentials and Discord endpoints for exfiltration; the implant targets LSASS memory, browser-stored credentials, and cryptocurrency wallets, encrypting and Base64-encoding data before segmented Discord delivery. Defenders should correlate anomalous traffic to multiple AI-provider APIs with LSASS access, process-injection behavior, persistence changes, and Discord communications.