Kyber ransomware represents a significant threat through dual-platform deployment capabilities targeting VMware ESXi virtualization infrastructure and Windows file systems. During a March 2026 incident response engagement, two Kyber payloads were recovered from the same environment. The ESXi variant, written in C++, specifically targets VMware environments with datastore encryption, VM termination, and management interface defacement capabilities. The Windows variant, written in Rust, includes experimental Hyper-V targeting features. Both samples share campaign identifiers and Tor-based infrastructure, confirming coordinated cross-platform operations. Despite advertising post-quantum Kyber1024 encryption, the ESXi variant actually uses ChaCha8 with RSA-4096 key wrapping, while the Windows variant implements the claimed AES-256-CTR with Kyber1024 hybrid scheme. The ransomware includes anti-recovery measures, service termination, and effective encryption strategies designed to cause complete operational disr...
This investigation uncovered new tools and techniques used by the Curly COMrades threat actor to establish covert, long-term access to victim networks. The attackers exploited Hyper-V virtualization on compromised Windows 10 machines to create hidden remote operating environments. They deployed a minimalistic Alpine Linux-based virtual machine hosting custom malware for reverse shell and proxy operations. This approach effectively bypassed traditional host-based EDR detections. The threat actor also demonstrated persistence through PowerShell scripts, Kerberos ticket manipulation, and local account creation. International collaboration with the Georgian CERT aided in analyzing the command and control infrastructure.
