I'm working on a way to hook any API call to perform some verification on the function. (I'm creating a SandBox)
The first way that I think about, is with register key, and implement our own dll into MicrosoftNT to be able to redirect any defined syscall. https://www.apriorit.com/dev-blog/160-apihooks .
Problem? only work on 32 bit, and if the binarie is loading User32.dll, so it's abig issue.
The second way is to inject a dll into a process? Simple but impossible, most program is defended from those injection, so it's not possible.
The last way that I think was to modify the SSDT to change the function address by mine and redirect to the original by creating a driver. Or by InlineHook and just modify the first byte of each address that I want.
The Problem, only working on 32 bit, because windows add a PatchGuard on the Kernel, so we can't do that.
We can delete de PatchGuard but, anticheat will notice the technique.
For the Sandbox I think it won't be a problem to delete a PatchGuard.
The main problem is for real time analysis, I have no more idea how I can do to hook every API call that I want, on any windows OS. I mean on 32 and 62 bit.
I'm a beginner in this domain I started this week so I'm open to any suggestion.
You say you want to hook every API call for a sandbox but then reference the SSDT? Those are two very different things. Do you want to hook VirtualQuery(Ex) or do you want to hook NtQueryVirtualMemory? From kernel or user mode? Or maybe you're referring to all loaded module exports as well as kernel system services?
WinApi
Iterate all loaded modules as well as installing an event to hook all future modules loaded. For each one you will iterate all exports and apply a hook of your preference which all jump to some handler. This handler should be raw assembly that preserves the CPU state, calls some method that does the logging and filtering, restores CPU state, before finally jumping to the original.
Syscalls
Disable Patchguard and apply hooks to every method in the service table similar to the WinApi method described above. This is definitely not suitable for production for obvious reasons.
Use an instrumentation callback which uses ZwSetInformationProcess to redirect most syscalls to an arbitrary assembly block. You can extract the syscall id here as well as parameters. Universal support is an issue though as it wasn't introduced until W7 iirc and you have a lot of limitations prior to W10.
Map a wrapper module that has a hook for every syscall into each newly loaded process from kernel. These hooks will apply to ntdll and simply invoke an NtDeviceIoControlFile call with the syscall id and arguments, forwarding it to your kernel driver for processing. This is commonly employed by antivirus software to monitor user mode system calls without disrupting Patchguard.
The most approved method would probably be callbacks. You can register process and thread callbacks in kernel, stripping handle access at your leisure. This will give you full control over process and thread access from external processes, and you can add a file minfilter to similarly restrict access to the file system.
Related
I created 2 hooks in my host application. 1st is WH_MOUSE set specifically for Taskbar's thread. 2nd is global WH_KEYBOARD_LL hook (dwThreadId is set to 0).
As you can see in Process Explorer, the "local" hook actually injected my dll into specific explorer.exe thread. However, there is no indication that my 2nd global hook got injected into any other processes, yet it still works perfectly... Moreover, it also works for all the new processes I start, even after the hook was set! How SetWindowsHookEx manages that?
I read that it only applies to processes that load user32.dll. My weak suspicion is that in a case of global hook, Windows somehow injects my custom dll code into user32.dll "hook-chain". And then, when new process that loads user32.dll is started, it automatically loads my hook with it? Is this correct or is there some other mechanism at work?
_LL (low-level) hooks are not injected anywhere, win32k (the kernel part of the window manager) calls the hook callback function directly. This is why that thread needs a message loop. Low-level hooks are always "global".
MSDN says:
Be aware that the WH_MOUSE, WH_KEYBOARD, WH_JOURNAL*, WH_SHELL, and low-level hooks can be called on the thread that installed the hook rather than the thread processing the hook.
You should think of hooks as having 3 modes:
Low-level (keyboard and mouse only)
Thread specific
All threads
The last two might require Windows to inject the .dll.
I read here that the inverse is possible, but how does one achieve such a thing? I'd hope there's a simple way, similar to calling from a loaded DLL, but my google research comes up with nothing. My only other thought is that one could pass some predefined constants through WriteFile or DeviceIoControl that the driver parses like a switch statement to execute the relevant function; does a more direct method exist?
The question is why would you want to do it? Generally if you have to rely on some mechanism like this, you need to revisit the design of the application/driver that you are writing.
The correct way to do something in context of your user mode application is exactly what you described. You can do a DeviceIoControl call to your driver and the driver validates all the parameters that you have passed, then carries out the operation on behalf of the user mode call.
If for some reason, you need to call into kernel directly, you will have to resort to undocumented methods. There are ways to hook into kernel dispatch table and overwrite one of the dispatch handler to redirect the call to your function. But I hope you never ever ship anything like this to your customer. This is good for learning how the dispatch table works, etc but introduces several security nightmares. Ultimately your software should not be responsible for someone's machine getting hacked.
i would like to systemwide hook CreateProcessEx
it is redirects all windows calls into my wrapper function
where I will log names to textfile then call oruginal CreateProcessEx
Can it be easy and safely done ?
I would like hook all systemwide calls to it but not etternaly
for some period of time only.. How to do it?
If I will find the adress of this api call in ram then overvrite
it with call to my procedure, how then I will call the oryginal
function if there it is somewhat corrupted?
Hooking CreateProcess is the wrong approach for a few reasons. There is an approved mechanism for doing this sort of thing but you need a driver to be loaded. Your driver can then simply leverage the PsSetCreateProcessNotifyRoutine function.
With that said, would your needs not be served by using the auditing functionality built into Windows? Turning on process creation auditing will cause the system to write an event log entry whenever a process is created, detailing plenty of information about the process being started, including the image path.
CreateProcessEx() is a user-mode function. You have to patch it on a per-process basis. That means creating a DLL that is injected into every running process, such as by using SetWindowsHookEx() or the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows\AppInit_DLLs Registry key, and then have that DLL patch the PE Imports table of every process it is loaded into.
I am at the end of my rope here. I have been trying for three weeks now to get this information. Before I continue I want you to know I am not writing malware here. I am however writing a binary analysis tool that monitors the behavior of malware.
What I am trying to accomplish is either to hook or monitor CreateServiceW and CreateServiceA. The reason is I want to know what process invoked CreateService and what the binary is that is being registered as a service by the call.
I am tried everything from writing hook ZwRequestWaitReplyPort to intercept the LPC message, to writing a proxy DLL for advapi32.dll, and writing an inline hook for the CreateService function. None of these approaches have yielded results though. The proxy DLL was promising in testing, but didn't work when the official DLL in system32 was replaced with the proxy (BSOD). The inline hook would work if I could gain write access to the mapped area of memory the DLL lies in. But regardless my time is running out and I am desperately in need of an alternative.
I have looked at SetWindowsHookEx and it seems plausible that it might be able to intercept messages sent from the process to services.exe ...but I am not certain.
Can anyone point me in a good direction...I'm begging you.
"The inline hook would work if I could gain write access to the mapped area of memory the DLL lies in."
If it's a system that you fully control, why don't you have write access to the memory?
Use VirtualProtect to change the permissions to RWX and put your hook in. The ADVAPI32 CreateService routines are just stubs forwarded to sechost.dll via api-ms-service-management-l1-1-1.dll (due to MinWin) so there is already easy call instruction to hook.
I'd like to call my app from my driver when an interesting event happens in the Windows kernel. I need to be able to pass at least 4 bytes of data back to user mode. How to achieve this? These events might happen quite, but not too, often, so I don't want to build a queue system and use IOCTLs.
I was thinking of something like the driver gets loaded, the user mode app registers its callback using IOCTL and kernel keeps calling that callback when events happen and finally the user mode client unregisters the callback and no more data is send to user mode. Is this possible?
I'm new to kernel programming, so after a day of googling I decided to ask here. I've noticed that there isn't much discussion about the kernel and drivers. And even less proper docs.