Executive Summary
GreenBlood is a sophisticated ransomware operation employing a professional-grade encryptor written in the Go programming language. The group follows a double extortion model, exfiltrating sensitive data—up to 139 GB in documented cases—before deploying military-grade AES-256 and RSA encryption to lock victim files.
The technical workflow is highly automated, involving the deletion of Volume Shadow Copies (VSS), destruction of Windows Backup catalogs, and disabling of security software like Windows Defender via registry manipulation. The malware is designed for efficiency, using multi-threading for rapid encryption and specific routines to handle large files and various storage media, including network shares and USB drives.
This threat is significant due to its comprehensive anti-recovery strategies, including the encryption of the Windows Recovery Environment (WinRE) and the use of FIPS 140-3 validated cryptographic standards, which makes unauthorized decryption nearly impossible. The group maintains persistence through Windows service registration and performs self-deletion to hinder forensic investigations.