FrostyNeighbor / Ghostwriter (UNC1151) — ESET analysis corroborated, Poland / Lithuania / Ukraine in EU scope

ESET's 2026-05-14 analysis of activity observed since March 2026 documents an evolved spearphishing chain: (1) malicious PDFs impersonating Ukrtelecom with embedded redirect links, (2) RAR archives delivering JavaScript PicassoLoader variants, (3) server-side victim geo-validation (serves benign PDF to non-Ukrainian IPs) with system fingerprinting every 10 minutes to determine Cobalt Strike eligibility, (4) persistence via scheduled tasks and registry modifications. The previous Polish-targeting wave exploited CVE-2024-42009 (Roundcube XSS) for credential harvesting; WinRAR CVE-2023-38831 also referenced in the toolchain. The Belarus-aligned actor cluster (UNC1151, UAC-0057, TA445, Storm-0257, Umbral Bison, White Lynx) targets governmental, industrial, healthcare, and logistics sectors. EU scope: Poland, Lithuania, and Ukraine confirmed; broader Eastern European public-sector exposure inferred (ESET WeLiveSecurity; The Hacker News; daily 2026-05-15).

No named EU victim disclosures this run. Status update from the W19 long-running record (item:apt28-apt29-unc1151): ESET's documentation of the geofencing and 10-minute fingerprinting cadence is new operational detail not present in the W19 ABW tri-attribution coverage. Detection: outbound connections to Canarytokens-style endpoints used for fingerprinting; scheduled-task creation with random GUIDs spawned from Office process trees (T1053.005); child processes of WinRAR or archive handlers executing JavaScript (T1059.007); PicassoLoader staging behaviours.