A phishing HTML file masquerading as an invoice delivers a macro-enabled Excel workbook that drops and executes a multi-stage obfuscated HTA payload, ultimately injecting a reverse shell shellcode into rundll32.exe and establishing a C2 connection.
A .NET DLL decodes architecture-specific shellcode from an embedded base64 string, allocates executable memory, and spawns a thread to execute it. The shellcode performs NTDLL unhooking, AMSI and ETW patching before executing an embedded PE payload identified as a PoshC2 dropper.