A Windows framework for creating projects that want to hide from EDR. Includes hiding strings and obfuscating function calls in Rust. Creates and embeds a PE resource with XOR'd strings and AES encrypted payloads on every build. Provides position independant abstractions that work even in an unmapped pe file.

At the moment, the only way to get at the config is by editing the crate itself. It's not ideal, but I haven't figured out a way to get the build script to read something in the project it's been added to. My current suggestion is to clone this crate and put it next to your project, in whatever folder you have it in, and import it like so:

[dependencies]  
stealth-win = {path="../stealth-win"}  

You can then edit the config and embed any strings you would like into the PE resource, or change the padding size, etc. The build_config file is protected by a git feature that ignores changes to a file, so you can still contribute definitions, and change the config file!

STEALTH_NO_BUILD_SCRIPT

You can set STEALTH_NO_BUILD_SCRIPT to anything and it will cancel the build script portion of the crate. This is useful when you have an IDE that wil run cargo check every time you save a file, as to not build a whole new PE every time you save. I only know how to do this automatically when cargo check is run, for VSCode Rust Analyzer plugin.

Go to extensions -> Rust Analyzer ⚙ -> Extension Settings -> Search: "@ext:rust-lang.rust-analyzer check" -> Rust-analyzer > Check:Extra Env -> Edit in settings.json and add this to the json file.

"rust-analyzer.check.extraEnv": {
"STEALTH_NO_BUILD_SCRIPT" : "true"
}

If you would like to add new definitions to the dll modules, just keep the function type and wrapper function definitions in alphabetical order. I will work on making the struct definitions also alphabetical order.

If you have features you'd like to add, just make sure to follow the goals at the bottom of the page. Mainly the implementation of features that work in both a mapped and unmapped (like a reflective loader dll) state.

The build config is protected by git update-index --skipworktree, so your changes won't show up to that file! If you need to add something to the config while contributing, you can use git update-index --no-skipworktree ./build_src/build_config.rs to remove this flag. Just make sure to put it back when you are done updating the config file!

This is a class that will allow you to read a PE, regardless of if it is 32 bit or 64 bit. It is abstracted away with the use of if statements and TypeState abstraction. In it's current implementation, there is a possibility the compiler eventually uses memcpy (This was an issue with my first implementation, too). memcpy will cause this to not work in an unmapped PE, which is bad, because the crate Win API functions use it to get the resource from the consuming executable. For now, though, no such calls have been generated in my dev environment. I have recently taken the crate to \[no_std\], in the hope that I can avoid all calls to functions like memcpy

Resource file built with the build script every time build is ran. Randomizes the position of strings and payload, as well as padding between entries. This resource is put into your final EXE and can be indexed using util::get_resource_bytes with a resource_id, positon, and length.

Strings can be added to the binary in xor'd format with their own key, from the build_config.rs
You can use the built in crypto_util::get_xor_encrypted_bytes which returns an SVec, which contains the bytes of your string
(with no null terminator). You can push a 0 onto this svec, if you need to pass the string to a function that expects
a null terminated string. There are also util::compare_xor_str_and_str_bytes and util::compare_xor_str_and_w_str_bytes function which are there to aid in comparing the xor'd strings with non xor'd strings. You can get a slice from any pointer to a C string and the util::strlen function, which you can pass in to compare with these two functions, as well as the key to the xor string. This will not decrypt the string, but rather xor encrypt the target string in place, byte by byte, and compare to the xor'd string in the embedded PE resource. The const values to retrieve your strings from the PE resource have
the following values replaced by an underscore: " " "," "." "\0". These can be added to in the build_src::build_util::make_const_name function.

A vector type, mainly based on Vec\<T\> code that can be used in an unmapped PE, by utilizing the internal GetModuleHandle and GetProcAddress to call VirtualAlloc and VirtualFree to manage a buffer of whatever type you give it. This does not require that the PE you are running your code from is mapped into memory properly. It just matters that kernel32 and ntdll are mapped into memory in the process the code (unmapped dll) is running in, which it should be.

You can use an import-free version of the windows Global Allocator from this crate byt adding this to your project:

#[global_allocator]
static GLOBAL: NoImportAllocator = NoImportAllocator;

This is essentually a copy past of the standard library Global Allocator, but instead of keeping an atomic pointer around to the heap, it just calls GetProcessHeap with every allocation. This give you the ability to use the Vec\<T\> class, and any class that uses it, instead of the SVec class. Be warned, this global allocator will conflict with any Rust program that consumes you as a crate, if you are one. The Stringclass CAN be used, but any static strings in your own binary will not be accessible until your PE is mapped into memory properly.

For example, if I made that the default allocator for THIS crate, it would effect all consuming crates. This is why I include this and the SVec\<T\> type.

So far I have reimplemented file reading using NtReadFile. It's very similar to the standard library implementation, but for some reason it's half as fast. This could use some improvement, and file write would also be a good addition.

Windows API calls and structures, and wrappers to get and call these functions through internal GetModuleHandleX and GetProcAddresX, both of which use the internal xor string comparison algorithm to find the function call.

Add strings for your own GetModuleHandleXand GetProcAddresX searches, target file for shellcode or a DLL payload which is AES encrypted and stored in the embedded PE Resource with the strings. Can change the resource ID, resource file name or the range of randomly generated bytes between resource entries. More to come in the config. I would eventually like to figure out a way for the user to keep a config file in their project. As it stand, now. you need to edit the crate, itself.

I would like most of this code to be usable in an unmapped state, i.e, if you are trying to use this library in a reflective loader.

Eventually I would also like to include Arm Windows, as well!

This is just the start. The project started because I needed a way to hide my strings, but I didn't want to manually encrypt and pack strings into my project.

and maybe Linux internals, down the line, too!

Better static analysis would be good! Soon I want to test if I can get away with doing a lot more in front of Windows Defender purely based on the static analysis for rust binaries not being as good.

• make a todo list...