UAC-0099 Targets Ukrainian Government Personnel With ASHVEIN RAT Hiding Commands in HTML
Oct 08, 2026
Malware / Cyber Espionage
The Russia-aligned threat actor known as UAC-0099 has been attributed to a previously undocumented .NET infostealer and remote access trojan (RAT) codenamed ASHVEIN . According to TrendAI, the malware has been put to use in attacks targeting Ukrainian government personnel. The cybersecurity company is tracking the cluster under the name Earth Sirrush (previously SHADOW-EARTH-065). ASHVEIN, which its developers internally refer to as "TelemetryBrowser," brings together credential theft, surveillance, and remote-control capabilities. Its functionality includes credential theft from Chrome and Firefox, GDI-based screenshot capture, file enumeration and retrieval, PowerShell remote shell execution, system fingerprinting, and encrypted command-and-control (C2) communications. "ASHVEIN also hides tasking inside invisible HTML elements," TrendAI said . "Some variants use a GitHub-based dead drop resolver as a fallback mechanism, while delivery methods inclu...