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mirror-ac/driver/integrity.c
lhodges1 c68473090b e
2023-12-27 14:35:46 +11:00

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#include "integrity.h"
#include "common.h"
#include "driver.h"
#include "modules.h"
#include "callbacks.h"
#include "ioctl.h"
#include <bcrypt.h>
#include <initguid.h>
#include <devpkey.h>
typedef struct _INTEGRITY_CHECK_HEADER
{
INT executable_section_count;
LONG total_packet_size;
} INTEGRITY_CHECK_HEADER, *PINTEGRITY_CHECK_HEADER;
#define MAX_MODULE_PATH 256
typedef struct _PROCESS_MODULE_INFORMATION
{
PVOID module_base;
SIZE_T module_size;
WCHAR module_path[MAX_MODULE_PATH];
} PROCESS_MODULE_INFORMATION, *PPROCESS_MODULE_INFORMATION;
typedef struct _PROCESS_MODULE_VALIDATION_RESULT
{
INT is_module_valid;
} PROCESS_MODULE_VALIDATION_RESULT, *PPROCESS_MODULE_VALIDATION_RESULT;
STATIC
NTSTATUS
InitiateEptFunctionAddressArrays();
STATIC
NTSTATUS
GetModuleInformationByName(_Out_ PRTL_MODULE_EXTENDED_INFO ModuleInfo, _In_ LPCSTR ModuleName);
STATIC
NTSTATUS
StoreModuleExecutableRegionsInBuffer(_Outptr_result_bytebuffer_(*BytesWritten) PVOID* Buffer,
_In_ PVOID ModuleBase,
_In_ SIZE_T ModuleSize,
_Out_ _Deref_out_range_(>, 0) PSIZE_T BytesWritten);
STATIC
NTSTATUS
MapDiskImageIntoVirtualAddressSpace(_Inout_ PHANDLE SectionHandle,
_Outptr_result_bytebuffer_(*Size) PVOID* Section,
_In_ PUNICODE_STRING Path,
_Out_ _Deref_out_range_(>, 0) PSIZE_T Size);
STATIC
NTSTATUS
ComputeHashOfBuffer(_In_ PVOID Buffer,
_In_ ULONG BufferSize,
_Outptr_result_bytebuffer_(*HashResultSize) PVOID* HashResult,
_Out_ _Deref_out_range_(>, 0) PULONG HashResultSize);
STATIC
VOID
GetNextSMBIOSStructureInTable(_Inout_ PSMBIOS_TABLE_HEADER* CurrentStructure);
STATIC
NTSTATUS
GetStringAtIndexFromSMBIOSTable(_In_ PSMBIOS_TABLE_HEADER Table,
_In_ INT Index,
_In_ PVOID Buffer,
_In_ SIZE_T BufferSize);
STATIC
NTSTATUS
GetAverageReadTimeAtRoutine(_In_ PVOID RoutineAddress, _Out_ PUINT64 AverageTime);
STATIC
NTSTATUS
RegistryPathQueryTestSigningCallback(IN PWSTR ValueName,
IN ULONG ValueType,
IN PVOID ValueData,
IN ULONG ValueLength,
IN PVOID Context,
IN PVOID EntryContext);
#ifdef ALLOC_PRAGMA
# pragma alloc_text(PAGE, GetDriverImageSize)
# pragma alloc_text(PAGE, GetModuleInformationByName)
# pragma alloc_text(PAGE, StoreModuleExecutableRegionsInBuffer)
# pragma alloc_text(PAGE, MapDiskImageIntoVirtualAddressSpace)
# pragma alloc_text(PAGE, ComputeHashOfBuffer)
# pragma alloc_text(PAGE, VerifyInMemoryImageVsDiskImage)
# pragma alloc_text(PAGE, RetrieveInMemoryModuleExecutableSections)
# pragma alloc_text(PAGE, GetNextSMBIOSStructureInTable)
# pragma alloc_text(PAGE, GetStringAtIndexFromSMBIOSTable)
# pragma alloc_text(PAGE, ParseSMBIOSTable)
# pragma alloc_text(PAGE, ValidateProcessLoadedModule)
# pragma alloc_text(PAGE, GetHardDiskDriveSerialNumber)
# pragma alloc_text(PAGE, ScanForSignature)
# pragma alloc_text(PAGE, InitiateEptFunctionAddressArrays)
# pragma alloc_text(PAGE, DetectEptHooksInKeyFunctions)
# pragma alloc_text(PAGE, RegistryPathQueryTestSigningCallback)
// #pragma alloc_text(PAGE, DetermineIfTestSigningIsEnabled)
#endif
/*
* note: this can be put into its own function wihtout an IRP as argument then it can be used
* in both the get driver image ioctl handler and the CopyDriverExecvutableRegions func
*/
NTSTATUS
GetDriverImageSize(_Inout_ PIRP Irp)
{
PAGED_CODE();
NTSTATUS status = STATUS_UNSUCCESSFUL;
LPCSTR driver_name = NULL;
SYSTEM_MODULES modules = {0};
PRTL_MODULE_EXTENDED_INFO driver_info = NULL;
GetDriverName(&driver_name);
if (!driver_name)
{
DEBUG_ERROR("GetDriverName failed with no status.");
return status;
}
status = GetSystemModuleInformation(&modules);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("GetSystemModuleInformation failed with status %x", status);
return status;
}
driver_info = FindSystemModuleByName(driver_name, &modules);
if (!driver_info)
{
DEBUG_ERROR("FindSystemModuleByName failed with no status code");
ExFreePoolWithTag(modules.address, SYSTEM_MODULES_POOL);
return STATUS_NOT_FOUND;
}
status = ValidateIrpOutputBuffer(Irp, sizeof(ULONG));
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ValidateIrpOutputBuffer failed with status %x", status);
goto end;
}
Irp->IoStatus.Information = sizeof(ULONG);
RtlCopyMemory(Irp->AssociatedIrp.SystemBuffer, &driver_info->ImageSize, sizeof(ULONG));
end:
if (modules.address)
ExFreePoolWithTag(modules.address, SYSTEM_MODULES_POOL);
return status;
}
STATIC
NTSTATUS
GetModuleInformationByName(_Out_ PRTL_MODULE_EXTENDED_INFO ModuleInfo, _In_ LPCSTR ModuleName)
{
PAGED_CODE();
NTSTATUS status = STATUS_UNSUCCESSFUL;
LPCSTR driver_name = NULL;
SYSTEM_MODULES modules = {0};
PRTL_MODULE_EXTENDED_INFO driver_info = NULL;
GetDriverName(&driver_name);
if (!driver_name)
{
DEBUG_ERROR("GetDriverName failed with no status.");
return status;
}
status = GetSystemModuleInformation(&modules);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("GetSystemModuleInformation failed with status %x", status);
return status;
}
driver_info = FindSystemModuleByName(driver_name, &modules);
if (!driver_info)
{
DEBUG_ERROR("FindSystemModuleByName failed with no status");
ExFreePoolWithTag(modules.address, SYSTEM_MODULES_POOL);
return STATUS_NOT_FOUND;
}
ModuleInfo->FileNameOffset = driver_info->FileNameOffset;
ModuleInfo->ImageBase = driver_info->ImageBase;
ModuleInfo->ImageSize = driver_info->ImageSize;
RtlCopyMemory(
ModuleInfo->FullPathName, driver_info->FullPathName, sizeof(ModuleInfo->FullPathName));
if (modules.address)
ExFreePoolWithTag(modules.address, SYSTEM_MODULES_POOL);
return status;
}
#define PE_TYPE_32_BIT 0x10b
STATIC
NTSTATUS
StoreModuleExecutableRegionsInBuffer(_Outptr_result_bytebuffer_(*BytesWritten) PVOID* Buffer,
_In_ PVOID ModuleBase,
_In_ SIZE_T ModuleSize,
_Out_ _Deref_out_range_(>, 0) PSIZE_T BytesWritten)
{
PAGED_CODE();
NTSTATUS status = STATUS_ABANDONED;
PIMAGE_DOS_HEADER dos_header = NULL;
PLOCAL_NT_HEADER nt_header = NULL;
PIMAGE_SECTION_HEADER section = NULL;
ULONG total_packet_size = 0;
ULONG num_sections = 0;
ULONG num_executable_sections = 0;
UINT64 buffer_base = 0;
ULONG bytes_returned = 0;
MM_COPY_ADDRESS address = {0};
ULONG buffer_size = 0;
if (!ModuleBase || !ModuleSize)
return STATUS_INVALID_PARAMETER;
/*
* The reason we allocate a buffer to temporarily hold the section data is that
* we don't know the total size until after we iterate over the sections meaning
* we cant set Irp->IoStatus.Information to the size of our reponse until we
* enumerate and count all executable sections for the file.
*/
buffer_size = ModuleSize + sizeof(INTEGRITY_CHECK_HEADER);
*BytesWritten = 0;
*Buffer = ExAllocatePool2(POOL_FLAG_NON_PAGED, buffer_size, POOL_TAG_INTEGRITY);
if (*Buffer == NULL)
return STATUS_MEMORY_NOT_ALLOCATED;
/*
* Note: Verifier doesn't like it when we map the module so rather then mapping it to our
* address space we will simply use MmCopyMemory on the module to avoid upsetting verifier
* :)
*/
dos_header = (PIMAGE_DOS_HEADER)ModuleBase;
/*
* The IMAGE_DOS_HEADER.e_lfanew stores the offset of the IMAGE_NT_HEADER from the base
* of the image.
*/
nt_header = (struct _IMAGE_NT_HEADERS64*)((UINT64)ModuleBase + dos_header->e_lfanew);
num_sections = nt_header->FileHeader.NumberOfSections;
/*
* The IMAGE_FIRST_SECTION macro takes in an IMAGE_NT_HEADER and returns the address of
* the first section of the PE file.
*/
section = IMAGE_FIRST_SECTION(nt_header);
buffer_base = (UINT64)*Buffer + sizeof(INTEGRITY_CHECK_HEADER);
for (ULONG index = 0; index < num_sections; index++)
{
if (section->Characteristics & IMAGE_SCN_MEM_EXECUTE)
{
/*
* Note: MmCopyMemory will fail on discardable sections.
*/
address.VirtualAddress = section;
status = MmCopyMemory((UINT64)buffer_base + total_packet_size,
address,
sizeof(IMAGE_SECTION_HEADER),
MM_COPY_MEMORY_VIRTUAL,
&bytes_returned);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("MmCopyMemory failed with status %x", status);
ExFreePoolWithTag(*Buffer, POOL_TAG_INTEGRITY);
*Buffer = NULL;
return status;
}
address.VirtualAddress = (UINT64)ModuleBase + section->PointerToRawData;
status = MmCopyMemory((UINT64)buffer_base + total_packet_size +
sizeof(IMAGE_SECTION_HEADER),
address,
section->SizeOfRawData,
MM_COPY_MEMORY_VIRTUAL,
&bytes_returned);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("MmCopyMemory failed with status %x", status);
ExFreePoolWithTag(*Buffer, POOL_TAG_INTEGRITY);
*Buffer = NULL;
return status;
}
total_packet_size += section->SizeOfRawData + sizeof(IMAGE_SECTION_HEADER);
num_executable_sections += 1;
}
section++;
}
INTEGRITY_CHECK_HEADER header = {0};
header.executable_section_count = num_executable_sections;
header.total_packet_size = total_packet_size + sizeof(INTEGRITY_CHECK_HEADER);
RtlCopyMemory(*Buffer, &header, sizeof(INTEGRITY_CHECK_HEADER));
*BytesWritten = total_packet_size + sizeof(INTEGRITY_CHECK_HEADER);
return status;
}
STATIC
NTSTATUS
MapDiskImageIntoVirtualAddressSpace(_Inout_ PHANDLE SectionHandle,
_Outptr_result_bytebuffer_(*Size) PVOID* Section,
_In_ PUNICODE_STRING Path,
_Out_ _Deref_out_range_(>, 0) PSIZE_T Size)
{
PAGED_CODE();
NTSTATUS status = STATUS_UNSUCCESSFUL;
HANDLE file_handle = NULL;
OBJECT_ATTRIBUTES object_attributes = {0};
PIO_STATUS_BLOCK pio_block = NULL;
UNICODE_STRING path = {0};
*Section = NULL;
*Size = 0;
RtlInitUnicodeString(&path, Path->Buffer);
InitializeObjectAttributes(
&object_attributes, &path, OBJ_KERNEL_HANDLE | OBJ_CASE_INSENSITIVE, NULL, NULL);
status = ZwOpenFile(&file_handle, GENERIC_READ, &object_attributes, &pio_block, NULL, NULL);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ZwOpenFile failed with status %x", status);
return status;
}
object_attributes.ObjectName = NULL;
/*
* Its important that we set the SEC_IMAGE flag with the PAGE_READONLY
* flag as we are mapping an executable image.
*/
status = ZwCreateSection(SectionHandle,
SECTION_ALL_ACCESS,
&object_attributes,
NULL,
PAGE_READONLY,
SEC_IMAGE,
file_handle);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ZwCreateSection failed with status %x", status);
ZwClose(file_handle);
*SectionHandle = NULL;
return status;
}
/*
* Mapping a section with the flag SEC_IMAGE (see function above) tells the os we
* are mapping an executable image. This then allows the OS to take care of parsing
* the PE header and dealing with all relocations for us, meaning the mapped image
* will be identical to the in memory image.
*/
status = ZwMapViewOfSection(*SectionHandle,
ZwCurrentProcess(),
Section,
NULL,
NULL,
NULL,
Size,
ViewUnmap,
MEM_TOP_DOWN,
PAGE_READONLY);
if (!NT_SUCCESS(status))
{
/*
* It is of utmost importants to mark SectionHandle as null after closing the
* handle from inside this function since an error has occured. The reason this is
* so important is because we are not responsible for freeing the function if it
* succeeds and even if it fails, we still allocate a value to the handle via
* ZwCreateSection. Meaning when the caller goes to check if the handle is null, it
* will not be null and will cause a double free.
*/
DEBUG_ERROR("ZwMapViewOfSection failed with status %x", status);
ZwClose(file_handle);
ZwClose(*SectionHandle);
*SectionHandle = NULL;
return status;
}
ZwClose(file_handle);
return status;
}
STATIC
NTSTATUS
ComputeHashOfBuffer(_In_ PVOID Buffer,
_In_ ULONG BufferSize,
_Outptr_result_bytebuffer_(*HashResultSize) PVOID* HashResult,
_Out_ _Deref_out_range_(>, 0) PULONG HashResultSize)
{
PAGED_CODE();
/*
* Since the windows documentation for the BCrypt functions contain the worst variable
* naming scheme in existence, I will try to explain what they do. (for my sake and any
* readers who also aren't smart enough to understand their otherworldy naming convention)
*
* algo_handle: handle to our BCrypt algorithm
* hash_handle: handle to our BCrypt hash
* bytes_copied: number of bytes that were copied to the output buffer when using
* BCryptGetProperty resulting_hash_size: this is the size of the final buffer hash, it
* should be equal to 32 (sizeof SHA256 hash) hash_object_size: the size of the buffer that
* will temporarily store our hash object hash_object: pointer to the buffer storing our
* hash object which is used to hash our buffer resulting_hash: pointer to the buffer that
* stores the resulting hash of our buffer, this is what we care about
*/
NTSTATUS status = STATUS_ABANDONED;
BCRYPT_ALG_HANDLE algo_handle = NULL;
BCRYPT_HASH_HANDLE hash_handle = NULL;
ULONG bytes_copied = 0;
ULONG resulting_hash_size = 0;
ULONG hash_object_size = 0;
PCHAR hash_object = NULL;
PCHAR resulting_hash = NULL;
*HashResult = NULL;
*HashResultSize = 0;
status = BCryptOpenAlgorithmProvider(&algo_handle, BCRYPT_SHA256_ALGORITHM, NULL, NULL);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("BCryptOpenAlogrithmProvider failed with status %x", status);
goto end;
}
/*
* Request the size of the hash object buffer, this is different then the buffer that
* will store the resulting hash, instead this will be used to store the hash object
* used to create the hash.
*/
status = BCryptGetProperty(algo_handle,
BCRYPT_OBJECT_LENGTH,
(PCHAR)&hash_object_size,
sizeof(ULONG),
&bytes_copied,
NULL);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("BCryptGetProperty failed with status %x", status);
goto end;
}
hash_object = ExAllocatePool2(POOL_FLAG_NON_PAGED, hash_object_size, POOL_TAG_INTEGRITY);
if (!hash_object)
{
status = STATUS_MEMORY_NOT_ALLOCATED;
goto end;
}
/*
* This call gets the size of the resulting hash, which we will use to allocate the
* resulting hash buffer.
*/
status = BCryptGetProperty(algo_handle,
BCRYPT_HASH_LENGTH,
(PCHAR)&resulting_hash_size,
sizeof(ULONG),
&bytes_copied,
NULL);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("BCryptGetProperty failed with status %x", status);
goto end;
}
resulting_hash =
ExAllocatePool2(POOL_FLAG_NON_PAGED, resulting_hash_size, POOL_TAG_INTEGRITY);
if (!resulting_hash)
{
status = STATUS_MEMORY_NOT_ALLOCATED;
goto end;
}
/*
* Here we create our hash object and store it in the hash_object buffer.
*/
status = BCryptCreateHash(
algo_handle, &hash_handle, hash_object, hash_object_size, NULL, NULL, NULL);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("BCryptCreateHash failed with status %x", status);
goto end;
}
/*
* This function hashes the buffer, but does NOT store it in our resulting buffer yet,
* we need to call BCryptFinishHash to retrieve the final hash.
*/
status = BCryptHashData(hash_handle, Buffer, BufferSize, NULL);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("BCryptHashData failed with status %x", status);
goto end;
}
/*
* As said in the previous comment, this is where we retrieve the final hash and store
* it in our output buffer.
*/
status = BCryptFinishHash(hash_handle, resulting_hash, resulting_hash_size, NULL);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("BCryptFinishHash failed with status %x", status);
goto end;
}
*HashResult = resulting_hash;
*HashResultSize = resulting_hash_size;
end:
if (algo_handle)
BCryptCloseAlgorithmProvider(algo_handle, NULL);
if (hash_handle)
BCryptDestroyHash(hash_handle);
if (hash_object)
ExFreePoolWithTag(hash_object, POOL_TAG_INTEGRITY);
return status;
}
/*
* 1. map driver to memory
* 2. store executable sections in buffer
* 3. do the same with the in-memory module
* 4. hash both buffers
* 5. compare
*/
NTSTATUS
VerifyInMemoryImageVsDiskImage(
//_In_ PIRP Irp
)
{
PAGED_CODE();
NTSTATUS status = STATUS_UNSUCCESSFUL;
UNICODE_STRING path = {0};
HANDLE section_handle = NULL;
PVOID section = NULL;
SIZE_T section_size = 0;
SIZE_T bytes_written = 0;
PVOID disk_buffer = NULL;
PVOID in_memory_buffer = NULL;
RTL_MODULE_EXTENDED_INFO module_info = {0};
UINT64 disk_base = 0;
UINT64 memory_base = 0;
PIMAGE_SECTION_HEADER disk_text_header = NULL;
PIMAGE_SECTION_HEADER memory_text_header = NULL;
PVOID disk_text_hash = NULL;
PVOID memory_text_hash = NULL;
ULONG disk_text_hash_size = 0;
ULONG memory_text_hash_size = 0;
SIZE_T result = 0;
LPCSTR driver_name = NULL;
GetDriverPath(&path);
GetDriverName(&driver_name);
if (!driver_name)
{
DEBUG_ERROR("GetDriverName failed with no status");
return status;
}
status =
MapDiskImageIntoVirtualAddressSpace(&section_handle, &section, &path, &section_size);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("MapDiskImageIntoVirtualAddressSpace failed with status %x", status);
return status;
}
status = StoreModuleExecutableRegionsInBuffer(
&disk_buffer, section, section_size, &bytes_written);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("StoreModuleExecutableRegionsInBuffer failed with status %x", status);
goto end;
}
/*
* Parse the in-memory module
*/
status = GetModuleInformationByName(&module_info, driver_name);
if (!NT_SUCCESS(status) || !module_info.ImageBase || !module_info.ImageSize)
{
DEBUG_ERROR("GetModuleInformationByName failed with status %x", status);
goto end;
}
status = StoreModuleExecutableRegionsInBuffer(
&in_memory_buffer, module_info.ImageBase, module_info.ImageSize, &bytes_written);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("StoreModuleExecutableRegionsInBuffer failed with status %x", status);
goto end;
}
disk_base = (UINT64)((UINT64)disk_buffer + sizeof(INTEGRITY_CHECK_HEADER) +
sizeof(IMAGE_SECTION_HEADER));
memory_base = (UINT64)((UINT64)in_memory_buffer + sizeof(INTEGRITY_CHECK_HEADER) +
sizeof(IMAGE_SECTION_HEADER));
disk_text_header =
(PIMAGE_SECTION_HEADER)((UINT64)disk_buffer + sizeof(INTEGRITY_CHECK_HEADER));
memory_text_header =
(PIMAGE_SECTION_HEADER)((UINT64)in_memory_buffer + sizeof(INTEGRITY_CHECK_HEADER));
if (!disk_base || !memory_base || !disk_buffer || !in_memory_buffer)
{
DEBUG_ERROR("Buffer(s) are null. An error has occured.");
goto end;
}
if (disk_text_header->SizeOfRawData != memory_text_header->SizeOfRawData)
{
/* report or bug check etc. */
DEBUG_WARNING("Executable section sizes differ between images.");
goto end;
}
status = ComputeHashOfBuffer(
disk_base, disk_text_header->SizeOfRawData, &disk_text_hash, &disk_text_hash_size);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ComputeHashOfBuffer failed with status %x", status);
goto end;
}
status = ComputeHashOfBuffer(memory_base,
memory_text_header->SizeOfRawData,
&memory_text_hash,
&memory_text_hash_size);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ComputeHashOfBuffer failed with status %x", status);
goto end;
}
if (memory_text_hash_size != disk_text_hash_size)
{
DEBUG_WARNING(
"Error with the hash algorithm, hash sizes are different. An error has occured.");
goto end;
}
result = RtlCompareMemory(memory_text_hash, disk_text_hash, memory_text_hash_size);
if (result != memory_text_hash_size)
{
/* report etc. bug check etc. */
DEBUG_WARNING("Text section hashes are different, the section has been modified.");
goto end;
}
DEBUG_INFO("Text sections are valid. Integrity check has been complete.");
end:
if (section_handle)
ZwClose(section_handle);
if (section)
ZwUnmapViewOfSection(ZwCurrentProcess(), section);
if (disk_buffer)
ExFreePoolWithTag(disk_buffer, POOL_TAG_INTEGRITY);
if (in_memory_buffer)
ExFreePoolWithTag(in_memory_buffer, POOL_TAG_INTEGRITY);
if (memory_text_hash)
ExFreePoolWithTag(memory_text_hash, POOL_TAG_INTEGRITY);
if (disk_text_hash)
ExFreePoolWithTag(disk_text_hash, POOL_TAG_INTEGRITY);
return status;
}
NTSTATUS
RetrieveInMemoryModuleExecutableSections(_Inout_ PIRP Irp)
{
PAGED_CODE();
NTSTATUS status = STATUS_UNSUCCESSFUL;
LPCSTR driver_name = NULL;
SIZE_T bytes_written = NULL;
PVOID buffer = NULL;
RTL_MODULE_EXTENDED_INFO module_info = {0};
GetDriverName(&driver_name);
if (!driver_name)
{
DEBUG_ERROR("GetDriverName failed with no status");
return status;
}
status = GetModuleInformationByName(&module_info, driver_name);
if (!NT_SUCCESS(status) || !module_info.ImageBase || !module_info.ImageSize)
{
DEBUG_ERROR("GetModuleInformationByName failed with status %x", status);
return status;
}
status = StoreModuleExecutableRegionsInBuffer(
&buffer, module_info.ImageBase, module_info.ImageSize, &bytes_written);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("StoreModuleExecutableRegionsInBuffe failed with status %x", status);
return status;
}
status = ValidateIrpOutputBuffer(Irp, bytes_written);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ValidateIrpOutputBuffer failed with status %x", status);
goto end;
}
Irp->IoStatus.Information = bytes_written;
RtlCopyMemory(Irp->AssociatedIrp.SystemBuffer, buffer, bytes_written);
end:
if (buffer)
ExFreePoolWithTag(buffer, POOL_TAG_INTEGRITY);
return status;
}
#define SMBIOS_TABLE 'RSMB'
#define NULL_TERMINATOR '\0'
/*
* From line 727 in the SMBIOS Specification:
*
* 727 <20> Each structure shall be terminated by a double-null (0000h), either directly following
* the 728 formatted area (if no strings are present) or directly following the last string. This
* includes 729 system- and OEM-specific structures and allows upper-level software to easily
* traverse the 730 structure table. (See structure-termination examples later in this clause.)
*
* TLDR is that if the first two characters proceeding the structure are null terminators, then
* there are no strings, otherwise to find the end of the string section simply iterate until there
* is a double null terminator.
*
* source: https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_2.7.1.pdf
*/
STATIC
VOID
GetNextSMBIOSStructureInTable(_Inout_ PSMBIOS_TABLE_HEADER* CurrentStructure)
{
PAGED_CODE();
PCHAR string_section_start =
(PCHAR)((UINT64)*CurrentStructure + (*CurrentStructure)->Length);
PCHAR current_char_in_strings = string_section_start;
PCHAR next_char_in_strings = string_section_start + 1;
for (;;)
{
if (*current_char_in_strings == NULL_TERMINATOR &&
*next_char_in_strings == NULL_TERMINATOR)
{
*CurrentStructure =
(PSMBIOS_TABLE_HEADER)((UINT64)next_char_in_strings + 1);
return;
}
current_char_in_strings++;
next_char_in_strings++;
}
}
/*
* Remember that the string index does not start from the beginning of the struct. For example, lets
* take RAW_SMBIOS_TABLE_02: the first string is NOT "Type" at index 0, the first string is
* Manufacturer. So if we want to find the SerialNumber, the string index would be 4, as the
* previous 3 values (after the header) are all strings. So remember, the index is into the number
* of strings that exist for the given table, NOT the size of the structure or a values index into
* the struct.
*
* Here we count the number of strings by incrementing the string_count each time we pass a null
* terminator so we know when we're at the beginning of the target string.
*/
STATIC
NTSTATUS
GetStringAtIndexFromSMBIOSTable(_In_ PSMBIOS_TABLE_HEADER Table,
_In_ INT Index,
_In_ PVOID Buffer,
_In_ SIZE_T BufferSize)
{
PAGED_CODE();
INT current_string_char_index = 0;
INT string_count = 0;
PCHAR current_string_char = (PCHAR)((UINT64)Table + Table->Length);
PCHAR next_string_char = current_string_char + 1;
for (;;)
{
if (*current_string_char == NULL_TERMINATOR && *next_string_char == NULL_TERMINATOR)
return STATUS_NOT_FOUND;
if (current_string_char_index >= BufferSize)
return STATUS_BUFFER_TOO_SMALL;
if (string_count + 1 == Index)
{
if (*current_string_char == NULL_TERMINATOR)
return STATUS_SUCCESS;
RtlCopyMemory((UINT64)Buffer + current_string_char_index,
current_string_char,
sizeof(CHAR));
current_string_char_index++;
goto increment;
}
if (*current_string_char == NULL_TERMINATOR)
{
current_string_char_index = 0;
string_count++;
}
increment:
current_string_char++;
next_string_char++;
}
return STATUS_NOT_FOUND;
}
/* for generic intel */
// #define SMBIOS_SYSTEM_INFORMATION_TYPE_2_TABLE 2
// #define MOTHERBOARD_SERIAL_CODE_TABLE_INDEX 4
/* for testing purposes in vmware */
// #define VMWARE_SMBIOS_TABLE 1
// #define VMWARE_SMBIOS_TABLE_INDEX 3
NTSTATUS
ParseSMBIOSTable(_Out_ PVOID Buffer,
_In_ SIZE_T BufferSize,
_In_ SMBIOS_TABLE_INDEX TableIndex,
_In_ ULONG TableSubIndex)
{
PAGED_CODE();
NTSTATUS status = STATUS_UNSUCCESSFUL;
PVOID firmware_table_buffer = NULL;
ULONG firmware_table_buffer_size = 0;
ULONG bytes_returned = 0;
PRAW_SMBIOS_DATA smbios_data = NULL;
PSMBIOS_TABLE_HEADER smbios_table_header = NULL;
PRAW_SMBIOS_TABLE_01 smbios_baseboard_information = NULL;
status = ExGetSystemFirmwareTable(SMBIOS_TABLE, 0, NULL, 0, &firmware_table_buffer_size);
/*
* Because we pass a null buffer here, the NTSTATUS result will be a BUFFER_TOO_SMALL error,
* so to validate this function call we check the return bytes returned (which indicate
* required buffer size) is above 0.
*/
if (firmware_table_buffer_size == NULL)
{
DEBUG_ERROR("ExGetSystemFirmwareTable call 1 failed to get required buffer size.");
return STATUS_BUFFER_TOO_SMALL;
}
firmware_table_buffer =
ExAllocatePool2(POOL_FLAG_NON_PAGED, firmware_table_buffer_size, POOL_TAG_INTEGRITY);
if (!firmware_table_buffer)
return STATUS_MEMORY_NOT_ALLOCATED;
status = ExGetSystemFirmwareTable(
SMBIOS_TABLE, NULL, firmware_table_buffer, firmware_table_buffer_size, &bytes_returned);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ExGetSystemFirmwareTable call 2 failed with status %x", status);
goto end;
}
smbios_data = (PRAW_SMBIOS_DATA)firmware_table_buffer;
smbios_table_header = (PSMBIOS_TABLE_HEADER)(&smbios_data->SMBIOSTableData[0]);
/*
* The System Information table is equal to Type == 2 and contains the serial number of the
* motherboard in the computer among various other things.
*
* source: https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_2.7.1.pdf
* line 823
*/
while (smbios_table_header->Type != TableIndex)
GetNextSMBIOSStructureInTable(&smbios_table_header);
status =
GetStringAtIndexFromSMBIOSTable(smbios_table_header, TableSubIndex, Buffer, BufferSize);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("GetStringAtIndexFromSMBIOSTable failed with status %x", status);
goto end;
}
end:
if (firmware_table_buffer)
ExFreePoolWithTag(firmware_table_buffer, POOL_TAG_INTEGRITY);
return status;
}
/*
* Because the infrastructure has already been setup to validate modules in the driver, that
* is how I will validate the usermode modules as well. Another reason is that the win32 api
* makes it very easy to take a snapshot of the modules and enumerate them with easy to use
* functions and macros.
*
* 1. Take a snapshot of the modules in the process from our dll
* 2. pass the image base, image size and the image path to our driver via an IRP
* 3. from our driver, to first verify the in memory module, attach to our protected process
* and using the base + size simply use StoreModuleExecutableRegionsInBuffer()
* 4. Next we use the path to map the image on disk into memory, and pass the image to
* StoreModuleExecutableRegionsInBuffer() just as we did before.
* 5. With the 2 buffers that contain both images executable regions, we hash them and compare
* for anomalies.
*
* note: Its important to realise that since these are user mode modules, they are often hooked
* by various legitimate programs - such as discord, nvidia etc. So this needs to be rethinked.
*/
NTSTATUS
ValidateProcessLoadedModule(_Inout_ PIRP Irp)
{
PAGED_CODE();
NTSTATUS status = STATUS_UNSUCCESSFUL;
BOOLEAN bstatus = FALSE;
PROCESS_MODULE_VALIDATION_RESULT validation_result = {0};
PPROCESS_MODULE_INFORMATION module_info = NULL;
PKPROCESS process = NULL;
KAPC_STATE apc_state = {0};
PVOID in_memory_buffer = NULL;
PVOID disk_buffer = NULL;
PVOID in_memory_hash = NULL;
PVOID disk_hash = NULL;
ULONG in_memory_hash_size = 0;
ULONG disk_hash_size = 0;
SIZE_T bytes_written = 0;
UNICODE_STRING module_path = {0};
HANDLE section_handle = NULL;
PVOID section = NULL;
ULONG section_size = 0;
status = ValidateIrpInputBuffer(Irp, sizeof(PROCESS_MODULE_INFORMATION));
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ValidateIrpInputBuffer failed with status %x", status);
return status;
}
module_info = (PPROCESS_MODULE_INFORMATION)Irp->AssociatedIrp.SystemBuffer;
GetProtectedProcessEProcess(&process);
/*
* Attach because the offsets given are from the process' context.
*/
KeStackAttachProcess(process, &apc_state);
status = StoreModuleExecutableRegionsInBuffer(
&in_memory_buffer, module_info->module_base, module_info->module_size, &bytes_written);
KeUnstackDetachProcess(&apc_state);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("StoreModuleExecutableRegionsInBuffer failed with status %x", status);
goto end;
}
status = ComputeHashOfBuffer(
in_memory_buffer, bytes_written, &in_memory_hash, &in_memory_hash_size);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ComputeHashOfBuffer failed with status %x", status);
goto end;
}
RtlInitUnicodeString(&module_path, &module_info->module_path);
status = MapDiskImageIntoVirtualAddressSpace(
&section_handle, &section, &module_path, &section_size);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("MapDiskImageIntoVirtualAddressSpace failed with status %x", status);
goto end;
}
status = StoreModuleExecutableRegionsInBuffer(
&disk_buffer, section, section_size, &bytes_written);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("StoreModuleExecutableRegionsInbuffer 2 failed with status %x", status);
goto end;
}
status = ComputeHashOfBuffer(disk_buffer, bytes_written, &disk_hash, &disk_hash_size);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ComputeHashOfBuffer 2 failed with status %x", status);
goto end;
}
if (!in_memory_hash || !disk_hash)
goto end;
bstatus = RtlEqualMemory(in_memory_hash, disk_hash, in_memory_hash_size);
status = ValidateIrpOutputBuffer(Irp, sizeof(PROCESS_MODULE_VALIDATION_RESULT));
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("Failed to validate IRP output buffer");
goto end;
}
/*
* Because each module is passed per IRP we don't need to send any reports
* to the queue we can simply pass it back to usermode via the same IRP.
* We also don't need to send any module information since usermode has everything
* needed to file the report.
*/
validation_result.is_module_valid = bstatus;
Irp->IoStatus.Information = sizeof(PROCESS_MODULE_VALIDATION_RESULT);
RtlCopyMemory(Irp->AssociatedIrp.SystemBuffer,
&validation_result,
sizeof(PROCESS_MODULE_VALIDATION_RESULT));
end:
if (section_handle)
ZwClose(section_handle);
if (section)
ZwUnmapViewOfSection(ZwCurrentProcess(), section);
if (in_memory_buffer)
ExFreePoolWithTag(in_memory_buffer, POOL_TAG_INTEGRITY);
if (in_memory_hash)
ExFreePoolWithTag(in_memory_hash, POOL_TAG_INTEGRITY);
if (disk_buffer)
ExFreePoolWithTag(disk_buffer, POOL_TAG_INTEGRITY);
if (disk_hash)
ExFreePoolWithTag(disk_hash, POOL_TAG_INTEGRITY);
return status;
}
/*
* TODO: Query PhysicalDrive%n to get the serial numbers for all harddrives, can use the command
* "wmic diskdrive" check in console.
*/
NTSTATUS
GetHardDiskDriveSerialNumber(_Inout_ PVOID ConfigDrive0Serial, _In_ SIZE_T ConfigDrive0MaxSize)
{
PAGED_CODE();
NTSTATUS status = STATUS_UNSUCCESSFUL;
HANDLE handle = NULL;
OBJECT_ATTRIBUTES attributes = {0};
IO_STATUS_BLOCK status_block = {0};
STORAGE_PROPERTY_QUERY storage_property = {0};
STORAGE_DESCRIPTOR_HEADER storage_descriptor_header = {0};
PSTORAGE_DEVICE_DESCRIPTOR device_descriptor = NULL;
UNICODE_STRING physical_drive_path = {0};
PCHAR serial_number = NULL;
SIZE_T serial_length = 0;
RtlInitUnicodeString(&physical_drive_path, L"\\DosDevices\\PhysicalDrive0");
/*
* No need to use the flag OBJ_FORCE_ACCESS_CHECK since we arent passing a handle given
* to us from usermode.
*/
InitializeObjectAttributes(&attributes,
&physical_drive_path,
OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,
NULL,
NULL);
status = ZwOpenFile(&handle, GENERIC_READ, &attributes, &status_block, NULL, NULL);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ZwOpenFile on PhysicalDrive0 failed with status %x", status);
goto end;
}
storage_property.PropertyId = StorageDeviceProperty;
storage_property.QueryType = PropertyStandardQuery;
status = ZwDeviceIoControlFile(handle,
NULL,
NULL,
NULL,
&status_block,
IOCTL_STORAGE_QUERY_PROPERTY,
&storage_property,
sizeof(STORAGE_PROPERTY_QUERY),
&storage_descriptor_header,
sizeof(STORAGE_DESCRIPTOR_HEADER));
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ZwDeviceIoControlFile first call failed with status %x", status);
goto end;
}
device_descriptor = ExAllocatePool2(
POOL_FLAG_NON_PAGED, storage_descriptor_header.Size, POOL_TAG_INTEGRITY);
if (!device_descriptor)
{
status = STATUS_MEMORY_NOT_ALLOCATED;
goto end;
}
status = ZwDeviceIoControlFile(handle,
NULL,
NULL,
NULL,
&status_block,
IOCTL_STORAGE_QUERY_PROPERTY,
&storage_property,
sizeof(STORAGE_PROPERTY_QUERY),
device_descriptor,
storage_descriptor_header.Size);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ZwDeviceIoControlFile second call failed with status %x", status);
goto end;
}
if (device_descriptor->SerialNumberOffset > 0)
{
serial_number =
(PCHAR)((UINT64)device_descriptor + device_descriptor->SerialNumberOffset);
serial_length = strnlen_s(serial_number, DEVICE_DRIVE_0_SERIAL_CODE_LENGTH) + 1;
if (serial_length > ConfigDrive0MaxSize)
{
DEBUG_ERROR(
"Serial length is greater then the allocated buffer size for the drives serial number.");
status = STATUS_BUFFER_TOO_SMALL;
goto end;
}
RtlCopyMemory(ConfigDrive0Serial, serial_number, serial_length);
}
DEBUG_INFO("Successfully retrieved hard disk serial number.");
end:
if (handle)
ZwClose(handle);
if (device_descriptor)
ExFreePoolWithTag(device_descriptor, POOL_TAG_INTEGRITY);
return status;
}
// VOID
// EnumeratePciDevices()
//{
// NTSTATUS status;
// PZZWSTR device_interfaces;
// PWSTR list_base;
// DEVPROPKEY key = { 0 };
// UNICODE_STRING symbolic_link = { 0 };
// WCHAR device_id[ 512 ];
// PZZWSTR current_string = NULL;
// SIZE_T string_length = 0;
//
// /* PCI guid */
// CONST GUID guid = { 0x5b45201d, 0xf2f2, 0x4f3b, 0x85, 0xbb, 0x30, 0xff, 0x1f, 0x95, 0x35,
// 0x99 };
//
// status = IoGetDeviceInterfaces(
// &guid,
// NULL,
// NULL,
// &device_interfaces
// );
//
// if ( !NT_SUCCESS( status ) )
// {
// DEBUG_LOG( "IoGetDeviceInterfaces failed with status %x", status );
// return;
// }
//
// current_string = device_interfaces;
//
// while ( *current_string != NULL_TERMINATOR )
// {
// string_length = wcslen( current_string );
//
// symbolic_link.Buffer = current_string;
// symbolic_link.Length = string_length;
// symbolic_link.MaximumLength = string_length;
//
// DEBUG_LOG( "Device Interface: %wZ", symbolic_link );
//
// current_string += symbolic_link.Length + 1;
// }
//
// ExFreePoolWithTag( device_interfaces, NULL );
// }
PVOID
ScanForSignature(_In_ PVOID BaseAddress,
_In_ SIZE_T MaxLength,
_In_ LPCSTR Signature,
_In_ SIZE_T SignatureLength)
{
PAGED_CODE();
CHAR current_char = 0;
CHAR current_sig_char = 0;
for (INT index = 0; index < MaxLength; index++)
{
for (INT sig_index = 0; sig_index < SignatureLength + 1; sig_index++)
{
current_char = *(PCHAR)((UINT64)BaseAddress + index + sig_index);
current_sig_char = Signature[sig_index];
if (sig_index == SignatureLength)
return (PVOID)((UINT64)BaseAddress + index);
if (current_char != current_sig_char)
break;
}
}
return NULL;
}
/*
* Lets ensure to the compiler doens't optimise out our useless instructions...
*/
#pragma optimize("", off)
STATIC
UINT64
MeasureInstructionRead(_In_ PVOID InstructionAddress)
{
CONST UINT64 start = __readmsr(IA32_APERF_MSR) << 32;
CHAR value = *(PCHAR)InstructionAddress;
return (__readmsr(IA32_APERF_MSR) << 32) - start;
}
#pragma optimize("", on)
STATIC
UINT64
MeasureReads(_In_ PVOID Address, _In_ ULONG Count)
{
UINT64 read_average = 0;
UINT64 old_irql;
MeasureInstructionRead(Address);
old_irql = __readcr8();
__writecr8(HIGH_LEVEL);
_disable();
for (ULONG iteration = 0; iteration < Count; iteration++)
read_average += MeasureInstructionRead(Address);
_enable();
__writecr8(old_irql);
DEBUG_VERBOSE("EPT Detection - Read Average: %llx", read_average);
return read_average / Count;
}
#define EPT_CHECK_NUM_ITERATIONS 30
#define EPT_CONTROL_FUNCTIONS_COUNT 4
#define EPT_PROTECTED_FUNCTIONS_COUNT 2
#define EPT_MAX_FUNCTION_NAME_LENGTH 128
#define EPT_EXECUTION_TIME_MULTIPLIER 10
/*
* Even though we test for the presence of a hypervisor, we should still test for the presence
* of EPT hooks on key functions as this is a primary method for reversing AC's.
*
* Credits to momo5502 for the idea: https://momo5502.com/blog/?p=255
*
* [+] EPT: Read average: 14991c28f5c2
* [+] no EPT: Read average: 28828f5c28
*
* On average a read when HyperDbg's !epthook is active is around ~125x longer. Will need to
* continue testing with other HV's, however it is a good start.
*/
STATIC
NTSTATUS
GetAverageReadTimeAtRoutine(_In_ PVOID RoutineAddress, _Out_ PUINT64 AverageTime)
{
if (!RoutineAddress || !AverageTime)
return STATUS_UNSUCCESSFUL;
*AverageTime = MeasureReads(RoutineAddress, EPT_CHECK_NUM_ITERATIONS);
return *AverageTime == 0 ? STATUS_UNSUCCESSFUL : STATUS_SUCCESS;
}
/*
* todo: encrypt both arrays
*
* The goal with the control functions is to find a reference time for an average read on a
* function that is not EPT hooked. To accomplish this I've selected some arbitrary, rarely
* used functions that shouldn't really ever have an EPT hook active on them. This will give
* us a baseline that we can then average out to find a relatively accurate average read time.
*
* From here, we have an array of protected functions which are commonly hooked via EPT to
* reverse anti cheats. We then check the read times of these functions and compare them to
* the average of the read times for the control functions. If the read threshold exceeds a
* multiple of 10, we can be fairly certain an EPT hook is active.
*
* Each time we measure the read we perform 30 iterations to ensure we get a consistent result
* aswell as disabling interrupts + raising IRQL to ensure the test is as accurate as possible.
*
* The following open source Intel VT-X hv's w/ EPT functionality have been tested and detected
* in a non vm environment:
*
* HyperDbg !epthook (https://github.com/HyperDbg/HyperDbg): detected
* DdiMon (https://github.com/tandasat/DdiMon): detected
*/
WCHAR CONTROL_FUNCTIONS[EPT_CONTROL_FUNCTIONS_COUNT][EPT_MAX_FUNCTION_NAME_LENGTH] = {
L"RtlAssert",
L"PsAcquireSiloHardReference",
L"PsDereferencePrimaryToken",
L"ZwCommitEnlistment"};
WCHAR PROTECTED_FUNCTIONS[EPT_PROTECTED_FUNCTIONS_COUNT][EPT_MAX_FUNCTION_NAME_LENGTH] = {
L"ExAllocatePoolWithTag", L"MmCopyMemory"};
/*
* For whatever reason MmGetSystemRoutineAddress only works once, then every call
* thereafter fails. So will be storing the routine addresses in arrays since they
* dont change once the kernel is loaded.
*/
UINT64 CONTROL_FUNCTION_ADDRESSES[EPT_CONTROL_FUNCTIONS_COUNT] = {0};
UINT64 PROTECTED_FUNCTION_ADDRESSES[EPT_PROTECTED_FUNCTIONS_COUNT] = {0};
STATIC
NTSTATUS
InitiateEptFunctionAddressArrays()
{
PAGED_CODE();
UNICODE_STRING current_function;
for (INT index = 0; index < EPT_CONTROL_FUNCTIONS_COUNT; index++)
{
RtlInitUnicodeString(&current_function, CONTROL_FUNCTIONS[index]);
CONTROL_FUNCTION_ADDRESSES[index] = MmGetSystemRoutineAddress(&current_function);
if (!CONTROL_FUNCTION_ADDRESSES[index])
return STATUS_UNSUCCESSFUL;
}
for (INT index = 0; index < EPT_PROTECTED_FUNCTIONS_COUNT; index++)
{
RtlInitUnicodeString(&current_function, CONTROL_FUNCTIONS[index]);
PROTECTED_FUNCTION_ADDRESSES[index] = MmGetSystemRoutineAddress(&current_function);
if (!PROTECTED_FUNCTION_ADDRESSES[index])
return STATUS_UNSUCCESSFUL;
}
return STATUS_SUCCESS;
}
NTSTATUS
DetectEptHooksInKeyFunctions()
{
PAGED_CODE();
NTSTATUS status = STATUS_UNSUCCESSFUL;
UINT32 control_fails = 0;
UINT64 instruction_time = 0;
UINT64 control_time_sum = 0;
UINT64 control_average = 0;
status = InitiateEptFunctionAddressArrays();
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("InitiateEptFunctionAddressArrays failed with status %x", status);
return status;
}
for (INT index = 0; index < EPT_CONTROL_FUNCTIONS_COUNT; index++)
{
status = GetAverageReadTimeAtRoutine(CONTROL_FUNCTION_ADDRESSES[index],
&instruction_time);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("DetectEptPresentOnFunction failed with status %x", status);
control_fails += 1;
continue;
}
control_time_sum += instruction_time;
}
if (control_time_sum == 0)
return STATUS_UNSUCCESSFUL;
control_average = control_time_sum / (EPT_CONTROL_FUNCTIONS_COUNT - control_fails);
if (control_average == 0)
return STATUS_ABANDONED;
for (INT index = 0; index < EPT_PROTECTED_FUNCTIONS_COUNT; index++)
{
status = GetAverageReadTimeAtRoutine(PROTECTED_FUNCTION_ADDRESSES[index],
&instruction_time);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("DetectEptPresentOnFunction failed with status %x", status);
continue;
}
/* [+] EPT hook detected at function: ExAllocatePoolWithTag with execution time of:
* 149b7777777 */
if (control_average * EPT_EXECUTION_TIME_MULTIPLIER < instruction_time)
{
DEBUG_WARNING(
"EPT hook detected at function: %llx with execution time of: %llx",
PROTECTED_FUNCTION_ADDRESSES[index],
instruction_time);
/* close game etc. */
}
else
{
DEBUG_INFO("No ept hook detected at function: %llx",
PROTECTED_FUNCTION_ADDRESSES[index]);
}
}
return status;
}
STATIC
VOID
FindWinLogonProcess(_In_ PPROCESS_LIST_ENTRY Entry, _In_opt_ PVOID Context)
{
LPCSTR process_name = NULL;
PEPROCESS* process = (PEPROCESS*)Context;
if (!Context)
return;
process_name = PsGetProcessImageFileName(Entry->process);
if (!strcmp(process_name, "winlogon.exe"))
{
DEBUG_VERBOSE("32 bit WinLogon.exe process found at address: %llx",
(UINT64)Entry->process);
*process = Entry->process;
}
}
/*
* todo: for some reason this works flawlessy on my vm, but fails on my real pc...
*/
NTSTATUS
ValidateSystemModules()
{
NTSTATUS status = STATUS_UNSUCCESSFUL;
BOOLEAN bstatus = FALSE;
ANSI_STRING ansi_string = {0};
UNICODE_STRING path = {0};
ULONG section_size = 0;
HANDLE section_handle = NULL;
PVOID section = NULL;
PVOID disk_buffer = NULL;
ULONG disk_buffer_size = 0;
PVOID disk_hash = NULL;
ULONG disk_hash_size = 0;
UINT64 disk_text_base = 0;
UINT64 memory_text_base = 0;
ULONG memory_text_size = 0;
PVOID memory_hash = NULL;
ULONG memory_hash_size = 0;
PVOID memory_buffer = NULL;
ULONG memory_buffer_size = 0;
ULONG result = 0;
PEPROCESS process = NULL;
KAPC_STATE apc_state = {0};
SYSTEM_MODULES modules = {0};
PRTL_MODULE_EXTENDED_INFO module_info = NULL;
PIMAGE_SECTION_HEADER disk_text_header = NULL;
PIMAGE_SECTION_HEADER memory_text_header = NULL;
DEBUG_VERBOSE("Beginning to validate system modules.");
status = GetSystemModuleInformation(&modules);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("GetSystemModuleInformation failed with status %s", status);
return status;
}
/*
* Since ntoskrnl itself is a process, we skip it here - we will validate it elsewhere.
*/
for (INT index = 1; index < modules.module_count; index++)
{
module_info = (PRTL_MODULE_EXTENDED_INFO)((UINT64)modules.address +
index * sizeof(RTL_MODULE_EXTENDED_INFO));
RtlInitAnsiString(&ansi_string, module_info->FullPathName);
if (!ansi_string.Buffer)
{
DEBUG_ERROR("RtlInitAnsiString failed with status %x", status);
ansi_string.Buffer = NULL;
ansi_string.Length = 0;
ansi_string.MaximumLength = 0;
continue;
}
status = RtlAnsiStringToUnicodeString(&path, &ansi_string, TRUE);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("RtlAnsiStringToUnicodeString failed with status %x", status);
path.Buffer = NULL;
goto free_iteration;
}
status = MapDiskImageIntoVirtualAddressSpace(
&section_handle, &section, &path, &section_size);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("MapDiskImageIntoVirtualAddressSpace failed with status %x",
status);
goto free_iteration;
}
status = StoreModuleExecutableRegionsInBuffer(
&disk_buffer, section, section_size, &disk_buffer_size);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("StoreModuleExecutableRegionsInBuffer failed with status %x",
status);
goto free_iteration;
}
/*
* For win32k and related modules, because they are 32bit for us to read the memory
* we need to attach to a 32 bit process. A simple check is that the 32 bit image
* base wont be a valid address, while this is hacky it works. Then we simply attach
* to a 32 bit address space, in our case winlogon, which will allow us to perform
* the copy.
*/
if (!MmIsAddressValid(module_info->ImageBase))
{
DEBUG_VERBOSE(
"Win32k related module found, acquiring 32 bit address space...");
EnumerateProcessListWithCallbackRoutine(FindWinLogonProcess, &process);
if (!process)
goto free_iteration;
KeStackAttachProcess(process, &apc_state);
status = StoreModuleExecutableRegionsInBuffer(&memory_buffer,
module_info->ImageBase,
module_info->ImageSize,
&memory_buffer_size);
KeUnstackDetachProcess(&apc_state);
}
else
{
status = StoreModuleExecutableRegionsInBuffer(&memory_buffer,
module_info->ImageBase,
module_info->ImageSize,
&memory_buffer_size);
}
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("StoreModuleExecutableRegionsInbuffer 2 failed with status %x",
status);
goto free_iteration;
}
disk_text_base = (UINT64)disk_buffer + sizeof(INTEGRITY_CHECK_HEADER) +
sizeof(IMAGE_SECTION_HEADER);
memory_text_base = (UINT64)((UINT64)memory_buffer + sizeof(INTEGRITY_CHECK_HEADER) +
sizeof(IMAGE_SECTION_HEADER));
disk_text_header =
(PIMAGE_SECTION_HEADER)((UINT64)disk_buffer + sizeof(INTEGRITY_CHECK_HEADER));
memory_text_header =
(PIMAGE_SECTION_HEADER)((UINT64)memory_buffer + sizeof(INTEGRITY_CHECK_HEADER));
if (!disk_text_base || !memory_text_base || !disk_buffer || !memory_buffer ||
!MmIsAddressValid(disk_buffer) || !MmIsAddressValid(memory_buffer))
{
DEBUG_ERROR("Buffer(s) are null. An error has occured.");
goto free_section;
}
if (disk_text_header->SizeOfRawData != memory_text_header->SizeOfRawData)
{
DEBUG_WARNING("Executable section sizes differ between images.");
goto free_iteration;
}
status = ComputeHashOfBuffer(
disk_text_base, disk_text_header->SizeOfRawData, &disk_hash, &disk_hash_size);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ComputeHashOfBuffer failed with status %s", status);
goto free_iteration;
}
status = ComputeHashOfBuffer(memory_text_base,
memory_text_header->SizeOfRawData,
&memory_hash,
&memory_hash_size);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("ComputeHashOfBuffer failed with status %x", status);
goto free_iteration;
}
if (!MmIsAddressValid(memory_hash) || !MmIsAddressValid(disk_hash))
goto free_iteration;
result = RtlCompareMemory(memory_hash, disk_hash, memory_hash_size);
if (result = memory_text_header->SizeOfRawData)
DEBUG_VERBOSE("Module executable sections are valid for the module: %s",
module_info->FullPathName);
else
DEBUG_WARNING("Module regions are not valid for module: %s",
module_info->FullPathName);
free_iteration:
if (memory_buffer)
ExFreePoolWithTag(memory_buffer, POOL_TAG_INTEGRITY);
if (memory_hash)
ExFreePoolWithTag(memory_hash, POOL_TAG_INTEGRITY);
if (disk_buffer)
ExFreePoolWithTag(disk_buffer, POOL_TAG_INTEGRITY);
if (disk_hash)
ExFreePoolWithTag(disk_hash, POOL_TAG_INTEGRITY);
free_section:
if (section_handle)
ZwClose(section_handle);
if (section)
ZwUnmapViewOfSection(ZwCurrentProcess(), section);
/*
* Its times like this where you see why allocating all local variables at the
* beginning of the function may not be so ideal...
*/
if (path.Buffer)
{
RtlFreeUnicodeString(&path);
path.Buffer = NULL;
path.Length = 0;
path.MaximumLength = 0;
}
ansi_string.Buffer = NULL;
ansi_string.Length = 0;
ansi_string.MaximumLength = 0;
section_handle = NULL;
section = NULL;
memory_buffer = NULL;
memory_hash = NULL;
disk_buffer = NULL;
disk_hash = NULL;
}
if (modules.address)
ExFreePoolWithTag(modules.address, SYSTEM_MODULES_POOL);
return status;
}
/*
* After some further research it appears that performing integrity checks the same way as
* validating other modules is not as straight forward as there are many (thousands) of hooks that
* take place in a legitmate ntoskrnl.exe image.
*
* Initial ideas are to maybe only validate the text sections of key functions such as MmCopyMemory,
* though this is quite manual and the potential to miss functions could be common.
*
* Need to do some more research & testing in this department.
*/
NTSTATUS
ValidateNtoskrnl()
{
NTSTATUS status = STATUS_UNSUCCESSFUL;
SIZE_T bytes_written = 0;
KAPC_STATE apc_state = {0};
PVOID memory_buffer = NULL;
ULONG memory_buffer_size = 0;
PRTL_MODULE_EXTENDED_INFO module_info = NULL;
SYSTEM_MODULES modules = {0};
status = GetSystemModuleInformation(&modules);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("GetSystemModuleInformation failed with status %x", status);
return status;
}
module_info = (PRTL_MODULE_EXTENDED_INFO)modules.address;
DEBUG_VERBOSE("Module base: %llx", module_info->ImageBase);
PVOID buffer =
ExAllocatePool2(POOL_FLAG_NON_PAGED, module_info->ImageSize, POOL_TAG_INTEGRITY);
if (!buffer)
goto end;
status = MmCopyVirtualMemory(PsInitialSystemProcess,
module_info->ImageBase,
PsGetCurrentProcess(),
buffer,
module_info->ImageSize,
KernelMode,
&bytes_written);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("MmCopyVirtualMemory failed with status %x", status);
goto end;
}
status = StoreModuleExecutableRegionsInBuffer(
&memory_buffer, buffer, module_info->ImageSize, &memory_buffer_size);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("StoreModuleExecutableRegionsInBuffer failed with status %x", status);
goto end;
}
DEBUG_VERBOSE("buf size: %lx", memory_buffer_size);
end:
if (buffer)
ExFreePoolWithTag(buffer, POOL_TAG_INTEGRITY);
if (modules.address)
ExFreePoolWithTag(modules.address, SYSTEM_MODULES_POOL);
return status;
}
NTSTATUS
GetOsVersionInformation(_Out_ PRTL_OSVERSIONINFOW VersionInfo)
{
NTSTATUS status = STATUS_ABANDONED;
RTL_OSVERSIONINFOW info = {0};
if (!VersionInfo)
return STATUS_INVALID_PARAMETER;
status = RtlGetVersion(&info);
if (!NT_SUCCESS(status))
{
DEBUG_ERROR("RtlGetVersion failed with status %x", status);
return status;
}
VersionInfo->dwBuildNumber = info.dwBuildNumber;
VersionInfo->dwMajorVersion = info.dwMajorVersion;
VersionInfo->dwMinorVersion = info.dwMinorVersion;
VersionInfo->dwOSVersionInfoSize = info.dwOSVersionInfoSize;
VersionInfo->dwPlatformId = info.dwPlatformId;
RtlCopyMemory(
VersionInfo->szCSDVersion, info.szCSDVersion, sizeof(VersionInfo->szCSDVersion));
return status;
}
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