BlueDelta

APT28 Expands Espionage with New HOOKEDGE Backdoor Targeting European Organizations

The Russian-linked APT28 group, also known as BlueDelta, has deployed a new lightweight backdoor called HOOKEDGE as part of a cyber-espionage campaign against strategic European entities. The attacks, assessed with moderate confidence, targeted government, diplomatic, and defense manufacturing organizations in Romania, Spain, and Turkey between September 2025 and April 2026. Infection begins with spear-phishing emails delivering Microsoft Word documents containing malicious macros that mimic official Spanish government materials. Upon execution, the macros drop files, establish persistence via scheduled tasks, and deploy the HOOKEDGE backdoor written in batch scripts. The malware uses hidden Microsoft Edge instances and the legitimate webhook.site service to blend command-and-control traffic with normal web activity. In high-value victims, operators installed a second HOOKEDGE instance with five-minute check-ins for faster control and data collection. The backdoor shows strong code similarities to the older HEADLACE implant previously attributed to the same group.