InvisibleFerret Loads a Cython Extension from a User Path

Daniel Jeremiah@daniyyell

•updated Jun 20, 2026•1•0•2

Detects Python loading a .pyd or .so extension from common user-controlled or temporary directories (AppData, Temp, Downloads, Projects, /tmp/, /home/.../Downloads/) rather than a trusted package installation. This behavior is indicative of the InvisibleFerret malware, which uses Cython extensions for its operations.