OpenSSF/OSV advisory MAL-2026-12216 confirms this npm version as malicious. stellarfix ships a.NET Windows executable at bin/stellarfn.exe and a postinstall.js that enumerates bin/*.exe and unconditionally launches the first one via execFileSync during npm install. The package.json declares scripts.postinstall=node postinstall.js, so the binary runs automatically on any Windows installer...
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in stellarfix (npm)
Details
stellarfix ships a.NET Windows executable at bin/stellarfn.exe and a postinstall.js that enumerates bin/*.exe and unconditionally launches the first one via execFileSync during npm install. The package.json declares scripts.postinstall=node postinstall.js, so the binary runs automatically on any Windows installer. The bundled binary contains class and P/Invoke symbols consistent with a full remote-access trojan: a ClientSocket/ConnectServer C2 channel with AES-encrypted traffic, an XLogger module using SetWindowsHookEx / LowLevelKeyboardProc / WM_KEYDOWN / ToUnicodeEx to capture keystrokes and GetForegroundWindow / GetActiveWindowTitle to capture focused-window context, a SendBot/ChatID exfiltration pipeline, ProcessCritical (SetCurrentProcessIsCritical) anti-termination, an Uninstaller routine, a USBSpread module (USBThread/USBStart/USBCode) for removable-media propagation, a Plugin loader, and OpenUrl/ReportWindow/Monitoring command handlers. The package contains no legitimate library code; its sole install-time effect is delivering and running this binary on the installer's host.
Decision reason
OpenSSF Malicious Packages via OSV confirms stellarfix@1.0.0 as malicious (MAL-2026-12216): Malicious code in stellarfix (npm)