Phishing and Trojanized Installers Deliver Remote Access Trojans via Multi-Stage, Evasion-Focused Infection Chains
Multiple active malware campaigns are delivering remote access trojans (RATs) using deceptive lures and multi-stage execution chains designed to evade endpoint defenses. Malwarebytes reported a campaign dubbed DEAD#VAX that distributes a file masquerading as a “PDF” but actually delivered as a virtual hard disk (.vhd) hosted via IPFS; when opened, Windows mounts the VHD and the victim is tricked into launching a Windows Script File (.wsf) that ultimately deploys AsyncRAT. The chain includes anti-analysis checks and process injection into Microsoft-signed binaries such as RuntimeBroker.exe, OneDrive.exe, taskhostw.exe, and sihost.exe, enabling hands-on-keyboard remote control while minimizing obvious on-disk artifacts.
Separately, reporting described DesckVB RAT v2.9, a modular .NET RAT using an obfuscated WSH JavaScript stager followed by PowerShell-based anti-analysis checks and an in-memory (“fileless”) loader, emphasizing persistence and a plugin-based architecture for post-compromise capabilities. Another campaign distributes ValleyRAT disguised as a legitimate LINE installer, targeting Chinese-speaking users; it attempts to weaken defenses by using PowerShell to add broad Windows Defender exclusions, performs sandbox checks (e.g., mutex/file-locking behaviors), and uses advanced injection (reported as PoolParty Variant 7 via Windows I/O completion ports) to hide within trusted processes while stealing credentials and maintaining C2 communications.
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