APT28’s Stealthy Multi-Stage Campaign Leveraging CVE‑2026‑21509 and Cloud C2 Infrastructure

APT28’s Stealthy Multi-Stage Campaign Leveraging CVE‑2026‑21509 and Cloud C2 Infrastructure By Pham Duy Phuc and Alex Lanstein · February 4, 2026 Updated February 9, 2026: This analysis has been updated to clarify malware naming conventions. Introduction Russian state-sponsored threat group APT28...

Russian APT28 Deploys “NotDoor” Backdoor Through Microsoft Outlook

APT28 hackers deploy NotDoor backdoor via Microsoft Outlook macros, using OneDrive sideloading to steal data and evade detection...