Ntdll hooking

Alas, from an attacker’s point of view, bypassing these 32-bit hooks and the mitigations offered by them is rather trivial with the help of some well-known techniques . Then we will steer into NTDLL functions (NtOpenProcess, NtAllocateVirtualMemory, NtWriteVirtualMemory, NtCreateThreadEx) aka. At first, I create thread in existing process via CreateRemoteThread() then I load my dll via LoadLibrary and finally hook calls on PROCESS_ATTACH. It is extremely strange to see that particular NtDll function hooked (I cannot think of a use case where DRM or anything else would need a hook for that), but it is usually uPlay that does these 32-byte code dumps when hooks fail. dll'. If a product insert an inline hook in the NtCreateThreadEx function in the NTDLL module for monitoring purposes, we will not be able to scrape the syscall number correctly, leading to an undefined behaviour when we will try to manually invoke the syscall. Sometimes it seems such a vaste to write valuable code for large articles whose topic isn't directly related to the code. dll, wow64cpu. dll is a listed module in LCC. Example 1, ZwCreateFile 's disassembly for x86 processors, demonstrates how thin This is why malware often manually maps ntdll. RegMon no longer does it, and in general efforts are being made to make this harder. Note that I am not certain that bpm is smart enough to detect if an exported symbol resides within a non-code section (and if the exported symbol is folded into a code section, e. Finally, use SetWindowsHookEx to install the hook procedure address in the appropriate hook chain. Below, I present to you a fantastically hacked up Frida script. In the example below, we run the second instance of our process which tries to attach a debugger to its parent (the first instance of the sysenter instruction: the sysenter instruction uses the MSRs in order to quickly call into the kernel and is mainly used in newer versions of Windows. Figure 3: Ntdll function hook. exe"); PsLookupProcessByProcessId( ProcessId, &Process ); APC_STATE oldApc; Using the hook-free Lagos Island ntdll. NTSTATUS __stdcall _LdrLoadDll (PWSTR SearchPath OPTIONAL, PULONG DllCharacteristics OPTIONAL, PUNICODE_STRING DllName, PVOID *BaseAddress); typedef void (WINAPI * LdrLoadDll_) (PWSTR SearchPath OPTIONAL, PULONG DllCharacteristics OPTIONAL, The objective of inline patching is to redirect the syscall jump into the EDR analysis function. Child 3308 return value: 0xc0000034 -1073741772 Note that 0xc0000034 is defined as STATUS_OBJECT_NAME_NOT_FOUND, in other words, the filename is incorrect. "is it possible to do IAT hooking with Nt and Zw functions? if not, why? Figure 1 – Directly executing functions of the Kernel without calling functions from ntdll. dll, these hooks need to be removed by loading a fresh copy of ntdll. Hooking is a technique to intercept function calls/messages or events passed between software, or in this case malware. Hoped it helped! Thank you for sharing what worked for you, Zackoplayer1235! As this is a much older issue, though, I am unsure if this would still help for a similar issue today. So, in order to acheive this goal, I went on EasyHook, which seems easy and robust. Compile the code and use inline-execute to run it. dll library is to call the GetProcAddress. If the bot begins execution at the second thread routine or at the hook procedure mentioned in Possibility 1, it follows a different initialization sequence that involves contacting FormgrabberPathUrl then installing Detours hooks at the entry points of the following API functions: NTDLL!NtQueryDirectoryFile NTDLL!NtVdmControl System call hook example - posted in Source Codes: #include stdafx. Rootkits for example can hook API calls to make themselves invisible from analysis tools, while we as For example, restoring the original code for hooked functions within ntdll. dll errors result from a corrupt or damaged version of the ntdll. dll - posted in Virus, Trojan, Spyware, and Malware Removal Help: Hello there! I am posting this from an infected Note that I am not certain that bpm is smart enough to detect if an exported symbol resides within a non-code section (and if the exported symbol is folded into a code section, e. Dynamic DLL Replacement. dll", "RtlAllocateHeap", Hook_HeapAlloc, TRUE); It seems that WriteProcessMemory API sucessfully change the import. Please try to use Windbg tool to check which method in your application is the root cause of this problem. The final step is the most significant part. An additional issue that arises from this hooking technique, is the forceful reallocation of Copy-on-Write memory pages that are commonly shared between multiple processes in order to save up memory. After everything has been prepared, the remote hook can be placed When one API is set with an inline hook, it calls a function of the ntdll module, which is actually the disguised FormBook malware. A catalog of NTDLL kernel mode to user mode callbacks, part 2: KiUserExceptionDispatcher. The purpose of the emulator is to detect more obscure hooks as well as accurately determine the destination of the hook, beyond resolving basic jump and call instructions. The value stored in register eax is a system Hook Shadow SSDT. HookDump also examines multiple DLL’s instead of just looking at NTDLL, the list of libraries is stored in the source file LibraryList. Next, it creates a file in %TEMP% which holds its payload code using TxF (which prevents it from being scanned by AV when written to disk). e. My hook function doesn't get a hit when DeviceIOControl call is from kernel to user mode. For example, in pure systems the ntdll. They use a fresh copy to bypass any hooks placed within the original copy of ntdll. dll is responsible for setting up the relevant function call arguments on the stack, then moving the system call number from the NtWriteFile call in the EAX register and executing the syscall instruction. 4. Here is a document about how to fix ntdll. DLL to intercept system service requests before the processor transitions to kernel-mode such as by intercepting executions at _wow64cpu. Stack Exchange Network Stack Exchange network consists of 178 Q&A communities including Stack Overflow , the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. In order to be the most verbose possible, I decided to hook the ntdll. Although some of the callbacks share certain similarities in their modes of operation, there remain significant differences between each of them, in The purpose of the emulator is to detect more obscure hooks as well as accurately determine the destination of the hook, beyond resolving basic jump and call instructions. $ parent. "is it possible to do IAT hooking with Nt and Zw functions? if not, why? Now let’s discuss what the NTDLL hooking entails. hooking this or any system call is a very bad idea. application, not any other processes. dll). The associated import library, Ntdll. After the analysis done by the EDR then the call is returned to the original NTDLL code. dll before it gets loaded into memory. h> /* Target System: Windows 10 x64-Bit Hook exported windows 10 x64 system calls */ NTSTATUS NTAPI pfnCallbackkNtTerminateProcess(HANDLE ProcessHandle, NTSTATUS ExitStatus); typedef LONG(NTAPI *pfnOrigNtTerminateProcess)(HANDLE ProcessHandle, NTSTATUS ExitStatus); BYTE bBytes[20] = { 0x4C, 0x8B, 0xD1, 0xB8 31 ntdll. Wow64SystemServiceCall is not a fixed address like SharedUserData!SystemCallStub, instead it’s the absolute address of a function within the wow64 ntdll. What is hooking? Hooking is a technique to alter the behavior of an application, allowing EDR tools to monitor the execution flow that occurs in a process, gather information for behavior-based analytics and detect suspicious and malicious activity. exe, when created from the above created process, LCC. From user-mode, you could hook a WoW64 routine or the call gate code page in NTDLL. This sysenter instruction: the sysenter instruction uses the MSRs in order to quickly call into the kernel and is mainly used in newer versions of Windows. Page 1 of 2 - Avoid people hooking WriteProcessMemory - posted in Programming: Hello, I have an application that injects a dll using manual mapping. From what I can gather, " ntdll!DbgUiRemoteBreakIn is used by the debugger to break in to a process, and the debugger assumes that the local address of DbgUiRemoteBreakIn matches the remote address of DbgUiRemoteBreakIn in the target process. dll. I suspect this is being caused by uPlay's overlay. In 32-bit systems, it is possible to monitor system calls in the kernel by hooking the SSDT. Faulting module path: C:\Windows\SYSTEM32\ntdll. and hook the Import address table to override the address of NtQuerySystemInformation. Looking at our Mimikatz graph, here is where we currently are in our execution. dll API as it is the lowest level that you can get to, right in front of the kernel's doorstep. dll from disk and restoring the original section. By hooking NTDLL, execution flow is redirected to the EDR memory space and functions (such as a DLL). This obfuscation is designed to confuse analysts. All you have to do is go to you pc settings, go to advanced settings and the change you virtual memory to a bigger amount. g. dll calls via dll injection. dll per the second technique may trigger detection by an EDR which performs process self-validation – periodically verifying that hooks are intact, and the third technique may be detected by a hook on the ntdll function LdrLoadDll which may determine that an attempt is It is in IAT, but in normal cases executables will never directly import anything from ntdll. dll seems to have been corrupted by one of the many updates I received. However in Windows Vista and up (64 bits only). lib is available in the WDK. Many security products monitor certain APIs through hooking, and this malware intends to disable the usermode hooks in ntdll’s address space by overwriting them. dll file itself, corrupt hardware drivers, or issues between Windows and other programs. > > Now I want to access the buffer that has been modified by original call. Hooking : Here is definition of Hooking from Wikipedia : In computer programming, the term hooking covers a range of techniques used to alter or augment the behaviour of an operating system, of applications, or of other software components by intercepting function calls or messages or events passed between software components. Unhooking. dll _RtlUserThreadStart + 0x1b 0x771cac3c C:\Windows\SysWOW64\ntdll. The objective of inline patching is to redirect the syscall jump into the EDR analysis function. A good example of where this is applicable is on hooks placed by carberp within the native call stubs of ntdll. It is in IAT, but in normal cases executables will never directly import anything from ntdll. dll module is loaded once and shared between all processes. In order to set 64-bit hooks in 32-bit processes, you’ll need tools for: Setting hooks Hooking NtCreateSection() is a much more reasonable thing to do - if we intercept a call to NtCreateSection() with the request of mapping the executable file as an image (SEC_IMAGE attribute), combined with the request of page protection that allows execution, we can be sure that the process is about to be launched. One of NTDLL's primary jobs is to initialize a register with a system-call number that identifies the service in the kernel being called, and to execute a system-call trap. See full list on apriorit. Report Id: e9223ba9-f5a3-11e5-9bef-402cf414e963 . FormBook modifies the code of the hooked APIs so it first calls the local hook function within FormBook, and then, after the message has been handled, it returns to Windows 10 x64 (WOW64) Native function no longer call FS: [0xC0], instead they call a pointer in the same way x86 used to call KiFastSystemCall. Hooking NtCreateSection() is a much more reasonable thing to do - if we intercept a call to NtCreateSection() with the request of mapping the executable file as an image (SEC_IMAGE attribute), combined with the request of page protection that allows execution, we can be sure that the process is about to be launched. dll - posted in Virus, Trojan, Spyware, and Malware Removal Help: Hello there! I am posting this from an infected The hooking function assumes, that the code in the memory of ntdll. exe using SysInternals ProcessExplorer. h is necessary for many constant definitions as well as the InitializeObjectAttributes macro. This Later the malware uses the most exciting technique to evade detection. Injection works fine, but then I want to log all registry and file system queries. For the CreateFile example, the NTDLL function ZwCreateFile is one of the routines invoked. ntdll!DbgUiDebugActiveProcess() ntdll!NtDebugActiveProcess() As only one debugger can be attached to a process at a time, a failure to attach to the process might indicate the presence of another debugger. However, the same antiviruses do not hook Ntdll in the native x64 processes. exe in suspended mode. exe) that is being created but not hooking correctly looks like this (tup-dllinject. If one of those processes alters a page, then Simply calling Ntdll version of function; Calling WoW64 version of the function; Direct Syscall Invocation; Original thunk tracing ; Secondary DLL mapping; Code splicing (byte stealing) All of these are great and work very well, however, they can all be stopped with a hook placed within the 64-bit version of ntdll. a constant, then it can't make such a detection). In a next step sandboxie tries to repair that by hooking most ntdll. DLL unhooking: Since EDR solutions monitor API calls by hooking ntdll. You can also use the LoadLibrary and GetProcAddress functions to dynamically link to The malware sets up a hook on NTDLL. dll, you will never catch direct API calls to ZwCreateFile. > > In my hook function I call the NtDll's original NtDeviceIoControl. e kernel32. The first thing that we need to do when trying to call some internal function of the ntdll. sys, ntdll. I'm currently working on hooking ntdll. NtQuerySystemInformation is in the 'Ntdll. dll loaded into the process when it was created, and force themselves to only use Nt* API calls located within that fresh copy of ntdll. The SSDT table holds the pointer to kernel functions, which are used upon system call invocation either by “int 0x2e” or sysenter instructions. The code simply checks a flag in the PEB A catalog of NTDLL kernel mode to user mode callbacks, part 2: KiUserExceptionDispatcher. NTSTATUS __stdcall _LdrLoadDll (PWSTR SearchPath OPTIONAL, PULONG DllCharacteristics OPTIONAL, PUNICODE_STRING DllName, PVOID *BaseAddress); typedef void (WINAPI * LdrLoadDll_) (PWSTR SearchPath OPTIONAL, PULONG DllCharacteristics OPTIONAL, Seriously sneaky rootkit infection. This is easy to do by checking the first 5 bytes of the function NtReadVirtualMemory that can be found in c:\windows\system32\ntdll. The value stored in register eax is a system From what I can gather, " ntdll!DbgUiRemoteBreakIn is used by the debugger to break in to a process, and the debugger assumes that the local address of DbgUiRemoteBreakIn matches the remote address of DbgUiRemoteBreakIn in the target process. dll clone Osiris then activates its process hollowing routine which launches a signed wermgr. VirtualQuery calls ntdll. As an added bonus Microsoft will soon allow a driver that uses these to be unloaded. GetProcessIdByName(ProcessId, "winlogon. dll from the 32-bit WOW64 mode. And the problem is that it doesn't work properly. exe, so it was injected): Figure 3: Setting the hook on the mapped ntdll!ZwClose. Apparently it looks like that ntdll. The technique can be used for malicious, as well as defensive cases. dll is always the original one and it copies it to the required buffer (rather than copying it from the raw image of ntdll. In the next section, we describe the overall process of hooking WOW64 processes and the tools you’ll need for accomplishing this task. Download demo projects and sources; Introduction. inl and was created by dumping a list of DLL’s loaded in explorer. Examining Smokeloader’s Anti Hooking technique. If the bot begins execution at the second thread routine or at the hook procedure mentioned in Possibility 1, it follows a different initialization sequence that involves contacting FormgrabberPathUrl then installing Detours hooks at the entry points of the following API functions: NTDLL!NtQueryDirectoryFile NTDLL!NtVdmControl However, most ntdll. dll syscalls and replacing them with a redirection to the own SbieDrv driver. com In order to be the most verbose possible, I decided to hook the ntdll. Rather all the imports will be from higher level WinAPI modules such as kernel32 (i. NTDLL has been hooked by the EDR application, as instructed by the driver after receiving the callback notification. h> /* Target System: Windows 10 x64-Bit Hook exported windows 10 x64 system calls */ NTSTATUS NTAPI pfnCallbackkNtTerminateProcess(HANDLE ProcessHandle, NTSTATUS ExitStatus); typedef LONG(NTAPI *pfnOrigNtTerminateProcess)(HANDLE ProcessHandle, NTSTATUS ExitStatus); BYTE bBytes[20] = { 0x4C, 0x8B, 0xD1, 0xB8 · fixed: hooking ntdll in non-large-address-aware x64 processes crashed · FOLLOW_JMP now follows up to 10 JMPs in a row · [driver] fixed denial of service vulnerability (found by Parvez Anwar) · [C++] fixed: CreateProcessEx for x64 processes sometimes failed · [C++] fixed: x64 hook installation sometimes (rarely) crashed Windows 10 x64 (WOW64) Native function no longer call FS: [0xC0], instead they call a pointer in the same way x86 used to call KiFastSystemCall. Note that the WDK header file Ntdef. Callers of ZwCreateFile must be running at IRQL = PASSIVE_LEVEL. Of course this assumption is valid only in optimistic case, and fails if the function was hooked before. In the hook, call the original user32!NtUserFindWindowEx() function. Hook LdrLoadDll to whitelist DLLs being loaded into a process. Otherwise, process hollowing would be detected. Yesterday, I listed the set of kernel mode to user mode callback entrypoints (as of Windows Server 2008). With this example, I just added the following for quick trial: CAPIHook g_HeapAlloc ("ntdll. One indication of the EDR hooking present is by checking if the function call does not start with the normal value 4c 8b d1 b8 N ntdll-refresher-hook-removal-bof Project information Project information Activity Labels Members Repository Repository Files Commits Branches Tags Contributors Graph Compare Locked Files Issues 0 Issues 0 List Boards Service Desk Milestones Iterations Merge requests 0 Merge requests 0 Requirements Requirements CI/CD CI/CD Pipelines Jobs Schedules Seriously sneaky rootkit infection. The direct system calls are usually used to silently inject malicious code into other processes. h #include <Windows. It does that by checking if the DR* registers are set to a value other than 0, and checks whether bytes of the called API is 0xCC, 0x3CD or 0xB0F. exe Universal System Call Hooking PoC (C) 2012 Jurriaan Bremer Started hooking child with process identifier: 3308 Child 3308 opens file: "hello world!". The InitInject function checks if the process is running natively (i. Most protection software will hook ntdll. For example if you only hook CreateFileW in kernel32. The steps of hooking Shadow is similar with SSDT hook, except that you have to attach to a user-mode GUI process before getting the base address of the Shadow. After everything has been prepared, the remote hook can be placed In order to hook ntdll!KiUserExceptionDispatcher, the first n instructions, where n is the number of instructions that it takes to cover at least 6 bytes, must be copied to a location that will be used by the hook to execute the actual ntdll!KiUserExceptionDispatcher. The first parameter is a handle to the DLL module that contains the function we’re trying An additional issue that arises from this hooking technique, is the forceful reallocation of Copy-on-Write memory pages that are commonly shared between multiple processes in order to save up memory. If one of those processes alters a page, then N ntdll-refresher-hook-removal-bof Project information Project information Activity Labels Members Repository Repository Files Commits Branches Tags Contributors Graph Compare Locked Files Issues 0 Issues 0 List Boards Service Desk Milestones Iterations Merge requests 0 Merge requests 0 Requirements Requirements CI/CD CI/CD Pipelines Jobs Schedules Hook LdrLoadDll to whitelist DLLs being loaded into a process. The NtWriteFile API from ntdll. In order to fix the mentioned issue, we need to restore the copy in-memory of the modified ntdll!NtQueryAttributesFile and ntdll!NtQueryAttributesFile take file object paths also, a create and query request is issued in the kernel for these operations) . dll', so far so good. After that, the CPU will jump into kernel-mode (ring 0). dll The stack from a process (RCC. The code simply checks a flag in the PEB Figure 3: Setting the hook on the mapped ntdll!ZwClose. How would i prevent people from hooking WriteProcessMemory in my application and dumping the buffer of WriteProcessMemory and so getting the data im writing? Then we will steer into NTDLL functions (NtOpenProcess, NtAllocateVirtualMemory, NtWriteVirtualMemory, NtCreateThreadEx) aka. Tools for Setting 64-Bit Hooks. You can also use the LoadLibrary and GetProcAddress functions to dynamically link to All you have to do is go to you pc settings, go to advanced settings and the change you virtual memory to a bigger amount. dll errors. dll API such as NtCreateFile() and NtOpenFile(). Kernel APIs and finally invoking Syscalls (System Calls) directly to perform DLL injection that bypasses the userland API hooking performed by AV/EDR solutions to detect the injection technique. For FindWindow(): Hook user32!NtUserFindWindowEx(). The driver then evaluates the calls and enforces the sandboxing rules, for example, no write access outside the sandbox and no read access to closed resources. The malware retrieves the text section base address of ntdll as displayed in the following image. section, however, I was only able to grab calls from only the example. Example 1, ZwCreateFile 's disassembly for x86 processors, demonstrates how thin My hook function is hit when call is made from User layer to the underlying kernel. SetWindowsHookEx passes the module handle, a pointer to the hook-procedure entry point, and 0 for the thread identifier, indicating that the hook procedure should be associated with all threads in the same desktop as the calling thread. Kernel32 is required to be at the same base address because there are a number of internal kernel32 Finally, use SetWindowsHookEx to install the hook procedure address in the appropriate hook chain. One indication of the EDR hooking present is by checking if the function call does not start with the normal value 4c 8b d1 b8 The hooking function assumes, that the code in the memory of ntdll. Although some of the callbacks share certain similarities in their modes of operation, there remain significant differences between each of them, in System call hook example - posted in Source Codes: #include stdafx. If one of those processes alters a page, then Hook Shadow SSDT. dll which eventually calls ZwCreateFile in ntdll. Now let’s discuss what the NTDLL hooking entails. Checking hook integrity. dll!LdrLoadDll overwriting it with relative opcode "0xe9" jump. NtQueryVirtualMemory). However, this isn’t enough for hooking the 64-bit Ntdll. Riccardo Ancarani put together a proof-of-concept to do this. Now my Question: If I loop through the Import address table of my process (putty. So how to I search up functions from a librarys i cannot find? HookDump is able to locate the original copy of NTDLL and examine it for hooks. 32-bit on a x86 system or 64-bit in a x64 system), or if its running under wow64 (that is a 32-bit process on a 64-bit system) and selects eider the native ntdll base address or the one of the wow64 ntdll. function sleep(ms) { return new Promise(resolve => setTimeout(resolve, ms)); } async function doItAll Due to some technical difficulties in hooking the 64-bit NTDLL, most security-related products hook only 32-bit modules in such processes. The shellcode wraps several API calls that researchers put breakpoints on with a function that detects if soft breakpoints or hardware breakpoints have been set. exe), I cannot find 'ntdll. However, most ntdll. Hooks in win32k. I wrote this little hook-engine for a much bigger article. You can refresh NTDLL within a Cobalt Strike Beacon with a Beacon Object File. For Parent Process Checks: Hook ntdll!NtQuerySystemInformation(). A well-placed hook in NTDLL will grant visibility into all of the userland APIs that use it. Kernel32 is required to be at the same base address because there are a number of internal kernel32 Callers of ZwCreateFile must be running at IRQL = PASSIVE_LEVEL. If it is called from the debugged process and the parent process looks suspicious, then return unsuccessfully from the hook. The syntax of the function can be obtained from [1] and looks like this: We need to pass two parameters to the function. I would recomend you look at the PsSetXxxNotifyRoutine calls it turns out you can do this without hooking. Great, we can unhook NTDLL and call functions without Frida seeing it! Now let’s write some Frida logic to periodically check the integrity of our hooks. Powerful x86/x64 Mini Hook-Engine. In order to unhook or, in other words, restore the hooked function to its initial state, we need to know how it looked like before it got modified by Cylance.