A China-nexus threat cluster designated UAT-11587 has been targeting government and policy organizations across eight Asian countries since September 2025, delivering a previously undocumented Rust-compiled backdoor called Antino. The campaign primarily affected Taiwan, India, Philippines, Cambodia, Pakistan, Thailand, Myanmar, and Syria through sophisticated spear-phishing operations using tailored political and diplomatic lures. The multi-stage infection chain leverages Cloudflare infrastructure for delivery and deploys Antino, which uniquely uses Microsoft 365 services—specifically Outlook and OneDrive—as dead-drop command-and-control channels rather than traditional C2 servers. The backdoor supports reconnaissance, command execution, file transfer, shellcode loading, and persistence establishment. Attribution to Chinese nexus is based on metadata containing Simplified Chinese artifacts, UTC+8 timestamps, use of China-focused Rust package mirrors, and targeting patterns consistent with Chinese intellige...
