Gamaredon, an FSB-linked threat actor, has deployed a highly evasive, fileless stealer dubbed GammaSteel targeting Ukrainian entities. The malware leverages Windows DPAPI to encrypt and stage payloads within the registry, actively monitoring local, network, and USB drives for sensitive documents to exfiltrate via legitimate cloud services and dynamic C2 infrastructure.
GammaWorm
3 posts
FSB’s matryoshka #3/3 – Gamaredon’s gifts that keeps unpacking – GammaSteel FSB’s matryoshka #2/3 – Gamaredon’s gifts that keeps unpacking – GammaLoad Gamaredon, a Russia-nexus threat actor, utilizes a multi-stage VBScript loader framework named GammaLoad to establish persistent access and deploy subsequent payloads like GammaSteel. The infection chain leverages Dead Drop Resolvers on legitimate platforms, stores C2 configurations in the Windows Registry, and uses Alternate Data Streams (ADS) combined with Scheduled Tasks for stealthy execution.
FSB’s matryoshka #1/3 – Gamaredon’s gifts that keeps unpacking – GammaPhish and GammaWorm Gamaredon (FSB) is conducting an ongoing cyberespionage campaign against Ukrainian targets using a modular, fileless infection chain. The attack leverages HTML smuggling and archive path traversal (CVE-2025-8088) for initial access, followed by the deployment of GammaWorm, which utilizes NTFS Alternate Data Streams (ADS) and Dead Drop Resolvers (DDRs) on legitimate platforms for persistence, propagation, and C2 communication.