C3: Leveraging the Native Messaging Application Programming Interface for Covert Command and Control

Traditional command and control (C2) frameworks struggle with evasion, automation, and resilience against modern detection techniques. This paper introduces covert C2 (C3), a novel C2 framework designed to enhance operational security and minimize detection. C3 employs a decentralized architecture, enabling independent victim communication with the C2 server for covert persistence. Its adaptable design supports diverse post-exploitation and lateral movement techniques for optimized results across various environments. Through optimized performance and the use of the native messaging API, C3 agents achieve a demonstrably low detection rate against prevalent Endpoint Detection and Response (EDR) solutions. A publicly available proof-of-concept implementation demonstrates C3’s effectiveness in real-world adversarial simulations, specifically in direct code execution for privilege escalation and lateral movement. Our findings indicate that integrating novel techniques, such as the native messaging API, and a decentralized architecture significantly improves the stealth, efficiency, and reliability of offensive operations. The paper further analyzes C3’s post-exploitation behavior, explores relevant defense strategies, and compares it with existing C2 solutions, offering practical insights for enhancing network security.