: A popular tool by hasherezade that converts an EXE into a DLL by exporting a Start function that points to the original EXE's entry point.
: Locate the IMAGE_FILE_HEADER and set the Characteristics field to include the IMAGE_FILE_DLL flag (typically 0x2000 ).
Works only for simple console EXEs with no GUI and no heavy side effects.
| Feature | EXE | DLL | |---------|-----|-----| | | WinMain or main | DllMain | | Execution | Creates its own process | Loaded into another process's address space | | Startup | OS loader starts a new thread | Called via LoadLibrary | | Exit Behavior | Terminates process; releases all resources | Unloaded; may leave resources if not freed | | Relocations | Optional (preferred base often fixed) | Required (can be loaded anywhere) | | Exports | Rarely exports functions | Designed to export functions | exe to dll
The critical difference lies in a specific attribute within the file header known as the Characteristics field. This field contains a bitmask that tells the Windows Loader how to handle the file.
Set IMAGE_FILE_DLL and clear IMAGE_FILE_EXECUTABLE_IMAGE .
A DLL is not an "incomplete EXE." It is a library that expects a host to call its functions. An EXE has a main function that owns the process lifecycle. Simply renaming program.exe to program.dll will fail because the Windows loader checks the Characteristics field in the PE header. : A popular tool by hasherezade that converts
If successful, you have converted the EXE to a functional DLL.
Converting known malware into a DLL for "analysis" is fine in a sandbox. Distributing such a DLL is illegal.
– EXEs often set a top-level filter that expects to exit the process. In a DLL, this can terminate the host. | Feature | EXE | DLL | |---------|-----|-----|
If you have the source code (or can reverse-engineer the logic), the proper solution is to and wrap it into a proper DLL.
In the world of software development and reverse engineering, the boundary between an executable application ( .exe ) and a dynamic link library ( .dll ) is often thinner than most users realize. While the average computer user sees an EXE as a program and a DLL as a mysterious background file, developers and security researchers understand that these binary formats share a fundamental structure.
The request to convert an executable to a library usually stems from three primary motivations: