Winsage
May 31, 2025
A new strain of malware has been operating undetected on Windows systems for several weeks, utilizing advanced evasion techniques that corrupt its Portable Executable (PE) headers to avoid detection. Security researchers discovered this malware embedded in the memory of a compromised system during an investigation, using a 33GB memory dump that revealed its presence in a dllhost.exe process with process ID 8200. The malware, classified as a Remote Access Trojan (RAT) by Fortinet, employs batch scripts and PowerShell commands for its attack and has capabilities for screenshot capture, remote server functionality, and system service manipulation. Its command and control infrastructure uses encrypted communications, complicating detection efforts. The malware's distinctive feature is the deliberate corruption of DOS and PE headers, which hinders reverse engineering and complicates the reconstruction of the executable from memory dumps. Researchers had to manually locate the malware’s entry point and resolve complex import tables for it to function in a controlled environment.
