OffensiveRust – Rust Weaponization for Red Team Engagements

offensiverust

OffensiveRust

My experiments in weaponizing Rust for implant development and general offensive operations.


Why Rust?

  • It is faster than languages like C/C++
  • It is multi-purpose language, bearing excellent communities
  • It has an amazing inbuilt dependency build management called Cargo
  • It is LLVM based which makes it a very good candidate for bypassing static AV detection
  • Super easy cross compilation to Windows from *nix/MacOS, only requires you to install the mingw toolchain, although certain libraries cannot be compiled successfully in other OSes.

Examples in this repo

FileDescription
Allocate_With_SyscallsIt uses NTDLL functions directly with the ntapi Library
Create_DLLCreates DLL and pops up a msgbox, Rust does not fully support this so things might get weird since Rust DLL do not have a main function
DeviceIoControlOpens driver handle and executing DeviceIoControl
EnableDebugPrivilegesEnable SeDebugPrivilege in the current process
Shellcode_Local_injectExecutes shellcode directly in local process by casting pointer
Execute_With_CMDExecutes cmd by passing a command via Rust
ImportedFunctionCallIt imports minidump from dbghelp and executes it
Kernel_Driver_ExploitKernel Driver exploit for a simple buffer overflow
Named_Pipe_ClientNamed Pipe Client
Named_Pipe_ServerNamed Pipe Server
Process_Injection_CreateThreadProcess Injection in remote process with CreateRemoteThread
UnhookingUnhooking calls
asm_syscallObtaining PEB address via asm
base64_system_enumBase64 encoding/decoding strings
http-https-requestsHTTP/S requests by ignoring cert check for GET/POST
patch_etwPatch ETW
ppid_spoofSpoof parent process for created process
tcp_ssl_clientTCP client with SSL that ignores cert check (Requires openssl and perl to be installed for compiling)
tcp_ssl_serverTCP Server, with port parameter(Requires openssl and perl to be installed for compiling)
wmi_executeExecutes WMI query to obtain the AV/EDRs in the host

Compiling the examples in this repo

This repository does not provide binaries, you’re gonna have to compile them yourself.

Install Rust
Simply download the binary and install.

This repo was compiled in Windows 10 so I would stick to it. As mentioned OpenSSL binaries will have depencency issues that will require OpenSSL and perl to be installed. For the TCP SSL client/server I recommend static build due to dependencies on the hosts you will execute the binaries. For creating a project, execute:
cargo new <name> This will automatically create the structured project folders with:

project
├── Cargo.toml
└── src
    └── main.rs

Cargo.toml is the file that contains the dependencies and the configuration for the compilation. main.rs is the main file that will be compiled along with any potential directories that contain libraries.

For compiling the project, go into the project directory and execute:
cargo build

This will use your default toolchain. If you want to build the final “release” version execute:
cargo build --release

For static binaries, in terminal before the build command execute:
"C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat"
set RUSTFLAGS=-C target-feature=+crt-static

In case it does not feel easy for you to read my code the way it is written,
you can also you the below command inside the project directory to format it in a better way
cargo fmt

Certain examples might not compile and give you some error, since it might require a nightly
build of Rust with the latest features. To install it just do:
rustup default nightly

The easiest place to find the dependencies or Crates as they are called.

Cross Compiling

Cross-Compiling requires to follow the instructions here By installing different toolchains, you can cross compile with the below command
cargo build --target <toolchain>

To see the installed toolchains on your system do:
rustup toolchain list

For checking all the available toolchains you can install in your system do:
rustup target list

For installing a new toolchain do:
rustup toolchain install <toolchain_name>

Optimizing executables for size

This repo contains a lot of configuration options and ideas about reducing the file size. Static binaries are usually quite big.

Pitfalls I found myself falling into

Careful of \0 bytes, do not forget them for strings in memory, I spent a lot of my time but windbg always helped resolving it.

Interesting Rust libraries

-WINAPI
WINAPI2
-Windows – This is the official Microsoft one that I have not played much with

OPSEC

-Even though Rust has good advantages it is quite difficult to get used to it and it ain’t very intuitive.
-Shellcode generation is another issue due to LLVM. I have found a few ways to approach this.
Donut sometimes does generate shellcode that works but depending on how the project is made, it might not.
In general, for shellcode generation the tools that are made should be made to host all code in .text segment, which leads to this amazing repo. There is a shellcode sample in this project that can show you how to structure your code for successfull shellcode generation.
In addition, this project also has a shellcode generator that grabs the .text segment of a binary and and dumps the shellcode after executing some patches.
This project grabs from a specific location the binary so I made a fork that receives the path of the binary as an argument here.

Other projects I have have made in Rust

UDPlant – Basically a UDP reverse shell
EDR Detector – Detects the EDRs of the installed system according to the .sys files installed
Lenum – A simple unix enumeration tool