Writing this loader from scratch is tedious. Fortunately, the security community has developed tools to automate this process.
Just like the OS loader, the shellcode must resolve the IAT.
Convert EXE to reflective DLL first, then to shellcode:
# Using PowerShell script
.\ConvertTo-Shellcode.ps1 -Binary payload.exe -Output payload.bin
Why go through the trouble of converting an EXE to shellcode instead of just dropping the EXE on disk?
Use a simple C loader to test your shellcode:
#include <windows.h>
int main() unsigned char shellcode[] = ... ; // from beacon.bin void exec = VirtualAlloc(0, sizeof(shellcode), MEM_COMMIT, PAGE_EXECUTE_READWRITE); memcpy(exec, shellcode, sizeof(shellcode)); ((void()())exec)(); return 0;
Compile and run. If your EXE was a message box, you should see the popup.
Here's an example C program that executes the shellcode:
#include <stdio.h>
#include <string.h>
int main()
char shellcode[] = "\x55\x48\x8b\x05\xb8\x13\x00\x00"; // Your shellcode here
int (*func)() = (int (*)())shellcode;
func();
return 0;
Compile and run it:
gcc -o execute_shellcode execute_shellcode.c
./execute_shellcode
For most use cases, Donut is your best option. If you need more control, use sRDI. Direct EXE to shellcode conversion without tools is complex and often fails - consider generating raw shellcode directly with msfvenom instead.
Converting an Executable (EXE) file into shellcode is a common technique used in red teaming and exploit development to execute programs in memory without dropping them on the disk. This process essentially wraps the PE (Portable Executable) file with a position-independent loader. Core Conversion Tools
The following tools are the industry standards for transforming compiled binaries into executable shellcode:
Donut: The most versatile tool for converting .NET Assemblies, EXE, and DLL files into position-independent shellcode.
Features: Supports x86 and x64, bypasses AMSI/WLDP, and offers compression (LZNT1, Xpress) to reduce payload size. Usage: donut.exe -f your_file.exe -o loader.bin.
Available on GitHub - TheWover/donut and as a Kali Linux package.
PE to Shellcode (pe2shc): Specifically designed to alter a PE file by adding a stub that allows it to be run as shellcode.
Benefit: It doesn't just hex-encode the file; it makes the PE itself executable as PIC (Position-Independent Code). Available on GitHub - hasherezade/pe_to_shellcode.
sRDI (Shellcode Reflective DLL Injection): Primarily for converting DLLs into shellcode that can be reflectively loaded. Available on GitHub - monoxgas/sRDI. Comparison of Methods Target Type Primary Use Case Output Format Donut .NET, EXE, DLL, JS, VBS Evasive in-memory execution binary (.bin), C, Python, Base64 pe2shc Windows PE (EXE/DLL) Direct conversion of PE to PIC binary (.bin) sRDI Windows DLL Stealthy reflective loading binary shellcode Advanced & Niche Options donut-shellcode | Kali Linux Tools
To convert a standard Portable Executable (EXE) into shellcode, you must transform it into Position Independent Code (PIC) convert exe to shellcode
that can execute directly from memory without the standard Windows OS loader. Stack Overflow Key Tools & Methods
The most reliable way to achieve this is using specialized "packers" or "loaders" that append a bootstrap to your EXE:
: The industry standard for converting VBScript, JScript, EXE, DLL, and .NET assemblies into position-independent shellcode. It works by creating a loader that handles relocation and API resolution in memory. pe_to_shellcode
: A tool by hasherezade that converts a PE file into a functional shellcode while keeping the output a valid PE. sRDI (Reflective DLL Injection)
: While primarily for DLLs, sRDI is often used in conjunction with EXE-to-shellcode workflows to load code reflectively without touching the disk. Why You Can't Just "Copy Bytes"
A standard EXE file starts with headers (MZ/PE) and metadata rather than executable instructions. If you inject raw EXE bytes into memory and try to run them, the process will crash because: Stack Overflow Hardcoded Addresses
: EXEs expect to be loaded at specific memory addresses (ImageBase). Dependencies
: EXEs rely on the OS loader to find and link external libraries (DLLs). Section Alignment
: The code is organized into sections (.text, .data) that must be mapped correctly to be executable. Stack Overflow Step-by-Step Conversion (Using Donut) binary or compile it from source. Run the command donut.exe -i your_program.exe -o loader.bin loader.bin file is your raw shellcode. Verification : You can test this shellcode using a simple C-based shellcode runner that allocates memory via VirtualAlloc and creates a thread to run the buffer. Bishop Fox to test your converted payload? Rust for Malware Development | Bishop Fox
The Art of Converting Executable Files to Shellcode: A Comprehensive Guide
In the realm of computer security and malware analysis, shellcode is a term that is often thrown around. But what exactly is shellcode, and how is it used in the cybersecurity landscape? More importantly, how can you convert an executable file to shellcode? In this article, we'll delve into the world of shellcode, explore its applications, and provide a step-by-step guide on how to convert an executable file to shellcode.
What is Shellcode?
Shellcode is a type of machine code that is injected into a vulnerable process to execute a specific task. It is typically used by attackers to gain control over a system, bypass security mechanisms, and execute malicious code. Shellcode is usually written in assembly language and is designed to be small, efficient, and stealthy.
How is Shellcode Used?
Shellcode has a variety of uses in the cybersecurity landscape. Here are a few examples:
Converting Executable Files to Shellcode
Converting an executable file to shellcode involves disassembling the executable file, extracting the machine code, and formatting it into a shellcode-compatible format. Here's a step-by-step guide on how to do it:
Tools Needed
Step 1: Disassemble the Executable File
The first step is to disassemble the executable file using objdump. This will give us the machine code and the assembly code.
objdump -d -M intel ./example.exe
This command will disassemble the example.exe file and output the disassembly in Intel syntax.
Step 2: Extract the Machine Code
The next step is to extract the machine code from the disassembly. We can use xxd to convert the binary data to hexadecimal format.
xxd -p -c 100 ./example.exe
This command will output the hexadecimal representation of the machine code in 100-byte chunks.
Step 3: Format the Machine Code as Shellcode
The machine code needs to be formatted into a shellcode-compatible format. This involves converting the hexadecimal data into a byte array.
echo "\x01\x02\x03\x04" > shellcode.bin
This command will create a byte array with the hexadecimal values.
Step 4: Assemble the Shellcode
The final step is to assemble the shellcode using nasm.
nasm -f elf32 shellcode.bin -o shellcode.o
This command will assemble the shellcode into an ELF32 object file.
Step 5: Inject the Shellcode
The final step is to inject the shellcode into a vulnerable process. This can be done using various techniques such as buffer overflow exploitation or code injection.
Example Use Case
Let's say we have an executable file called example.exe that we want to convert to shellcode. We can follow the steps outlined above to convert it to shellcode.
objdump -d -M intel ./example.exe
xxd -p -c 100 ./example.exe
echo "\x01\x02\x03\x04" > shellcode.bin
nasm -f elf32 shellcode.bin -o shellcode.o
Once we have the shellcode, we can inject it into a vulnerable process to execute the malicious code.
Conclusion
Converting an executable file to shellcode is a complex process that requires a deep understanding of assembly language, machine code, and operating system internals. In this article, we provided a comprehensive guide on how to convert an executable file to shellcode. We also explored the uses of shellcode in the cybersecurity landscape and provided an example use case.
Recommendations
Additional Resources
By following this guide, you'll be able to convert executable files to shellcode and gain a deeper understanding of the complex world of shellcode.
Converting a Windows executable (.exe) into shellcode involves transforming a standard Portable Executable (PE) Position-Independent Code (PIC)
that can run in memory without being loaded by the standard OS loader Popular Tools for Conversion
Several automated tools can wrap an existing EXE or DLL into a shellcode loader:
: A widely used generator that creates PIC from .NET assemblies, EXE files, and DLLs. It wraps the payload in a loader that handles memory decryption and execution. donut -f payload.exe -o payload.bin PE to Shellcode (pe2shc)
: Specifically designed to make a PE file runnable as shellcode by adding a specialized stub to the front. pe2shc.exe input.exe output.shc
: A multi-language tool (Python and Rust versions available) that converts EXEs to shellcode arrays for use in loaders. Manual Extraction Methods
If you are developing your own code specifically to be used as shellcode, you can extract it manually: hasherezade/pe_to_shellcode: Converts PE into a shellcode
Clone. Use recursive clone to get the repo together with all the submodules: git clone --recursive https://github.com/hasherezade/
mrd0x/pe2shc-to-cdb: Convert shellcode generated ... - GitHub
Title: Powerful but Niche – Not for Beginners Rating: 4/5 Stars
Review Body:
I’ve been experimenting with various methods to convert executables (EXEs) into position-independent shellcode for payload development and exploit research. After trying "convert exe to shellcode" (specifically tools like msfvenom or custom extractors like Donut or PE2SHC), here is my honest take.
The Good (What works):
The Bad (Limitations):
The Verdict:
Is this tool useful? Yes, absolutely for post-exploitation. If you are a penetration tester who already has a foothold and wants to run mimikatz.exe or adfind.exe without uploading the file to disk, this is a game-changer.
However, if you are a malware analyst or a CTF player looking for classic, small, assembly-level shellcode (like execve or MessageBox), you are better off writing it manually in assembly or using msfvenom with standard payloads.
Tip for users: Always use a proper loader script (C# or Python) with dynamic API resolution to make this actually work in the real world. Writing this loader from scratch is tedious
Would I recommend it? Yes, but only if you understand Windows PE loading mechanisms and have a reliable injector ready.