GREYVIBE — newly documented Russia-nexus cluster deploys five parallel attack chains against Ukraine with AI-generated lures and two PowerShell RATs

WithSecure Labs disclosed GREYVIBE on 28–29 May 2026, a previously-unnamed Russia-nexus threat cluster active since at least August 2025, targeting Ukrainian military, government, civilians, and businesses (WithSecure Labs, 2026-05-29; SecurityWeek, 2026-05-28). Five parallel attack chains: PhantomMail (spear-phishing with ZIP/RAR archives via Google Drive and 4sync), PhantomClick (fake CAPTCHA/ClickFix pages impersonating Zoom and LAPAS), PrincessClub (fraudulent adult-club sites with WebRTC-based social engineering), DroneLink (counterfeit Ukrainian Armed Forces charity sites), and Nebo (fake Russian military login portals). Core malware: LegionRelay (PowerShell RAT with file theft, screenshots, credential harvesting, RDP access; RC4 C2 comms), PhantomRelay (PowerShell RAT with dynamic script loading and watchdog persistence), and FallSpy (Android spyware for contact, call log, and geolocation extraction). Four custom obfuscators — LOOKVALPS, LOOKVALJS, DAYLIGHT, TEASOUP — were assessed as LLM-assisted developments. Attribution evidence: Russian-language panels and code comments; C2 servers in UTC+3 (Moscow time); OPSEC failures including public scan-platform uploads. WithSecure identifies possible links to UAC-0098 (former TrickBot associates). MITRE ATT&CK: T1566.001/T1566.002, T1059.001, T1005, T1204.001, T1133. Detection: alert on PowerShell spawned from archive-extraction utility parent processes; hunt scheduled tasks created by PowerShell beaconing to dynamic DNS; Android MDM alerts on sideloaded APKs accessing mic/camera. Organisations supporting Ukrainian government or civil-society counterparts are within the targeting scope.