CAPEv2 (capemon) hook(s) generator

This script automatically generates new hooks (hookdefs) for capemon, the CAPEv2 monitor. The hooks are generated according to the info specified in this repo. Please bear in mind the generated files are just skeletons to help you define new hooks, you must adapt them according to your needs.

Usage

The script requires close to zero configuration. If you want it to Google for the APIs not present in the downloaded winapi_categories.json file, just specify your Google API and Google CSE keys in the config.ini file.

Run python3 generate_hooks.py -h to print more information.

How does it work?

The script performs the following steps:

1. Check if API kes have been specified in config.ini to determine whether Google search is enabled.
2. Checks whether winapi_categories.json file is present in the current directory. If it isn't, the script downloads it.
3. Checks whether the original hooks.c file is present in the current directory. If it isn't, the script downloads it.
4. Parses hooks.c to get the APIs already hooked by CAPEv2.
5. Creates the skeleton files extended_hooks.c, extended_hooks.h and extended_hook_misc.c.
6. If --dll is specified, parse each path, extract its EAT and jump to step 8.
7. If --api is specified, parse each API call.
8. For every API call, check if it is already present in hooks.c. If it isn't try to generate its hook skeleton.
9. Look if the API call is present in winapi_categories.json. If it is, read its data, write the files and go back to 8 with the next API call.
10. If the Google search is enabled, Google for it in site:learn.microsoft.com. Scrape the first result (we assume it is the correct one), parse the data and go back to 8 with the next API call. If there are no Google results, go back to 8 with the next API call.

Example

Let's say you already configured your keys in the config.ini file (so the script uses Google to scrape learn.microsoft.com for the entries not present in the JSON file) and you want to generate capemon hooks skeleton for the following APIs: GetProcAddress, GetModuleHandleA, GetModuleHandleW, Sleep, CreateMutexA, CreateMutexW, GetVolumeInformationA and GetVolumeInformationW. You would run the script like so:

$ python3 generate_hooks.py --api GetProcAddress,GetModuleHandleA,GetModuleHandleW,Sleep,CreateMutexA,CreateMutexW,GetVolumeInformationA,GetVolumeInformationW

The script produces three files. Namely, extended_hooks.c, extended_hooks.h and extended_hook_misc.c with the following contents

extended_hooks.c example

/*
	File autogenerated by capemon hook generator (https://github.com/RazviOverflow/cape-hook-generator)
	The contents of this file can be appended to any array present in your local hooks.c.
	For example, hook_t full_hooks[].
*/

HOOK(Kernel32.dll, GetProcAddress),
HOOK(Kernel32.dll, GetModuleHandleA),
HOOK(Kernel32.dll, GetModuleHandleW),
HOOK(Kernel32.dll, Sleep),
HOOK(Kernel32.dll, CreateMutexA),
HOOK(Kernel32.dll, CreateMutexW),
HOOK(Kernel32.dll, GetVolumeInformationA),
HOOK(Kernel32.dll, GetVolumeInformationW),

extended_hooks.h example

/*
	File autogenerated by capemon hook generator (https://github.com/RazviOverflow/cape-hook-generator)
	The contents of this file can be appended to your local hooks.h
	WINAPI calling convention is assumed, but it might be incorrect!
*/

HOOKDEF(FARPROC, WINAPI, GetProcAddress,
	_In_ HMODULE hModule,
	_In_ LPCSTR lpProcName
);

HOOKDEF(HMODULE, WINAPI, GetModuleHandleA,
	_In_opt_ LPCSTR lpModuleName
);

HOOKDEF(HMODULE, WINAPI, GetModuleHandleW,
	_In_opt_ LPCWSTR lpModuleName
);

HOOKDEF(VOID, WINAPI, Sleep,
	_In_ DWORD dwMilliseconds
);

HOOKDEF(HANDLE, WINAPI, CreateMutexA,
	_In_opt_ LPSECURITY_ATTRIBUTES lpMutexAttributes,
  _In_           BOOL                  bInitialOwner,
  _In_opt_ LPCSTR                lpName
);

HOOKDEF(HANDLE, WINAPI, CreateMutexW,
	_In_opt_ LPSECURITY_ATTRIBUTES lpMutexAttributes,
  _In_           BOOL                  bInitialOwner,
  _In_opt_ LPCWSTR               lpName
);

HOOKDEF(BOOL, WINAPI, GetVolumeInformationA,
	_In_opt_  LPCSTR  lpRootPathName,
  _Out_opt_ LPSTR   lpVolumeNameBuffer,
  _In_            DWORD   nVolumeNameSize,
  _Out_opt_ LPDWORD lpVolumeSerialNumber,
  _Out_opt_ LPDWORD lpMaximumComponentLength,
  _Out_opt_ LPDWORD lpFileSystemFlags,
  _Out_opt_ LPSTR   lpFileSystemNameBuffer,
  _In_            DWORD   nFileSystemNameSize
);

HOOKDEF(BOOL, WINAPI, GetVolumeInformationW,
	_In_opt_  LPCWSTR lpRootPathName,
  _Out_opt_ LPWSTR  lpVolumeNameBuffer,
  _In_            DWORD   nVolumeNameSize,
  _Out_opt_ LPDWORD lpVolumeSerialNumber,
  _Out_opt_ LPDWORD lpMaximumComponentLength,
  _Out_opt_ LPDWORD lpFileSystemFlags,
  _Out_opt_ LPWSTR  lpFileSystemNameBuffer,
  _In_            DWORD   nFileSystemNameSize
);

extended_hook_misc.c example

/*
	File autogenerated by capemon hook generator (https://github.com/RazviOverflow/cape-hook-generator)
	The contents of this file can be appended to your local hook_{{category}}.c they belong.
	WINAPI calling convention is assumed, but it might be incorrect!
*/

HOOKDEF(FARPROC, WINAPI, GetProcAddress,
	_In_ HMODULE hModule,
	_In_ LPCSTR lpProcName
){
	DebuggerOutput("[***** DEBUG MESSAGE - EXTENDED HOOKS *****] Hooked GetProcAddress\n");
	FARPROC ret = Old_GetProcAddress(hModule,lpProcName);
	LOQ_bool("misc", ""); // Modify category and log according to your needs
	return ret;
}

HOOKDEF(HMODULE, WINAPI, GetModuleHandleA,
	_In_opt_ LPCSTR lpModuleName
){
	DebuggerOutput("[***** DEBUG MESSAGE - EXTENDED HOOKS *****] Hooked GetModuleHandleA\n");
	HMODULE ret = Old_GetModuleHandleA(lpModuleName);
	LOQ_bool("misc", ""); // Modify category and log according to your needs
	return ret;
}

HOOKDEF(HMODULE, WINAPI, GetModuleHandleW,
	_In_opt_ LPCWSTR lpModuleName
){
	DebuggerOutput("[***** DEBUG MESSAGE - EXTENDED HOOKS *****] Hooked GetModuleHandleW\n");
	HMODULE ret = Old_GetModuleHandleW(lpModuleName);
	LOQ_bool("misc", ""); // Modify category and log according to your needs
	return ret;
}

HOOKDEF(VOID, WINAPI, Sleep,
	_In_ DWORD dwMilliseconds
){
	DebuggerOutput("[***** DEBUG MESSAGE - EXTENDED HOOKS *****] Hooked Sleep\n");
	Old_Sleep(dwMilliseconds);
	LOQ_bool("misc", ""); // Modify category and log according to your needs
}

HOOKDEF(HANDLE, WINAPI, CreateMutexA,
	_In_opt_ LPSECURITY_ATTRIBUTES lpMutexAttributes,
  _In_           BOOL                  bInitialOwner,
  _In_opt_ LPCSTR                lpName
){
	DebuggerOutput("[***** DEBUG MESSAGE - EXTENDED HOOKS *****] Hooked CreateMutexA\n");
	HANDLE ret = Old_CreateMutexA(lpMutexAttributes,bInitialOwner,lpName);
	LOQ_bool("misc", ""); // Modify category and log according to your needs
	return ret;
}

HOOKDEF(HANDLE, WINAPI, CreateMutexW,
	_In_opt_ LPSECURITY_ATTRIBUTES lpMutexAttributes,
  _In_           BOOL                  bInitialOwner,
  _In_opt_ LPCWSTR               lpName
){
	DebuggerOutput("[***** DEBUG MESSAGE - EXTENDED HOOKS *****] Hooked CreateMutexW\n");
	HANDLE ret = Old_CreateMutexW(lpMutexAttributes,bInitialOwner,lpName);
	LOQ_bool("misc", ""); // Modify category and log according to your needs
	return ret;
}

HOOKDEF(BOOL, WINAPI, GetVolumeInformationA,
	_In_opt_  LPCSTR  lpRootPathName,
  _Out_opt_ LPSTR   lpVolumeNameBuffer,
  _In_            DWORD   nVolumeNameSize,
  _Out_opt_ LPDWORD lpVolumeSerialNumber,
  _Out_opt_ LPDWORD lpMaximumComponentLength,
  _Out_opt_ LPDWORD lpFileSystemFlags,
  _Out_opt_ LPSTR   lpFileSystemNameBuffer,
  _In_            DWORD   nFileSystemNameSize
){
	DebuggerOutput("[***** DEBUG MESSAGE - EXTENDED HOOKS *****] Hooked GetVolumeInformationA\n");
	BOOL ret = Old_GetVolumeInformationA(lpRootPathName,lpVolumeNameBuffer,nVolumeNameSize,lpVolumeSerialNumber,lpMaximumComponentLength,lpFileSystemFlags,lpFileSystemNameBuffer,nFileSystemNameSize);
	LOQ_bool("misc", ""); // Modify category and log according to your needs
	return ret;
}

HOOKDEF(BOOL, WINAPI, GetVolumeInformationW,
	_In_opt_  LPCWSTR lpRootPathName,
  _Out_opt_ LPWSTR  lpVolumeNameBuffer,
  _In_            DWORD   nVolumeNameSize,
  _Out_opt_ LPDWORD lpVolumeSerialNumber,
  _Out_opt_ LPDWORD lpMaximumComponentLength,
  _Out_opt_ LPDWORD lpFileSystemFlags,
  _Out_opt_ LPWSTR  lpFileSystemNameBuffer,
  _In_            DWORD   nFileSystemNameSize
){
	DebuggerOutput("[***** DEBUG MESSAGE - EXTENDED HOOKS *****] Hooked GetVolumeInformationW\n");
	BOOL ret = Old_GetVolumeInformationW(lpRootPathName,lpVolumeNameBuffer,nVolumeNameSize,lpVolumeSerialNumber,lpMaximumComponentLength,lpFileSystemFlags,lpFileSystemNameBuffer,nFileSystemNameSize);
	LOQ_bool("misc", ""); // Modify category and log according to your needs
	return ret;
}

Limitations

The script requires internet connection to be able to download both winapi_categories.json and hooks.c files, and also to use Google (in case it is configured).

Another limiation is the quota / search rate imposed by Google. As of right now, Google CSE (Custom Search Engine) API limits the automation to 100 searches per day.

WINAPI calling convention is assumed. Modify autogenerated files as needed.

Comments

• Changes to config.ini are ommited with git update-index --skip-worktree config.ini.