WinAPIEx

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0.8.2
2017 to 2018
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GitHub

Source code can be downloaded on GitHub.

bytecode77 / winapi-ex

Extensions to WinAPI.

WinAPIEx.h is the file you include. In addition to WinAPI, WinAPIEx has functions to simplify boilerplate code for repeating tasks, such as file/registry/process operations. The target audience is pentesters and developers who write C++ code that interacts with the operating system (Windows).


Minimalism

One .h and one .cpp file - for a reason

In pentesting scenarios, single binaries with no additional dependencies become handy. Deployment issues that manifest in undefined behavior can be avoided.

No classes & methods - just functions

Typically, a class wraps up an entire entity and all of its features, like the "Process" class in .NET Framework.

However, having a class that is not 100 % feature complete, means exporting the HANDLE, procceeding with WinAPI, and then going back to the class object instance. This ambiguousness can be avoided by either extending WinAPI as it is, or by wrapping up everything. The latter case is covered by frameworks, such as Qt or Boost.

In WinAPIEx, singular functions, like "DWORD GetProcessIdByName(LPCWSTR)" fit perfectly into the existing WinAPI function set. Existing code does not need to be migrated.


API Structure

Parameters and return values

In WinAPI, most commonly a function returns a BOOL value indicating success/failure with a parameter to an existing buffer. This way, buffers can be allocated on the stack and reused. For performance critical situations, less abstraction is nice. However, WinAPIEx is a little more abstract to become handy.

Examples:

  • A function that returns a string, returns LPWSTR, or NULL if it failed. This buffer has to be deleted after calling the function.
  • A function that returns a DWORD (or anything that is not a buffer), will either return 0, or -1 on failure, depending on the individual case. Or the function returns BOOL and accepts a LPDWORD parameter. Again, this is up to the individual case.

Function names & structure

WinAPI is flat when it comes to function names. The initial intent to design WinAPIEx this way is not especially comprehensive. That's why WinAPIEx has namespaces to separate functions a bit. The root namespace is "C". So by applying "using namespace C;" or "using namespace C::Environment;" there is quicker access to these functions.

Classes

No classes. There is just one struct, Array<T>. This is the most simplistic way to return an array of values, or NULL. And no further abstraction (getters/setters, etc.)

And no enums, to avoid casting back and forth between WinAPI const's and WinAPIEx enums. Otherwise, usage would be mixed and ambiguous. If you are looking for a framework instead, try Qt or Boost.

Unicode vs. ANSI

LPWSTR. No ANSI functions.


Precompiled Binaries

A few EXE and DLL files are included to become handy. All precompiled with /MT and in both x86 and x64.

PayloadExe.exe

Simple MessageBox that displays information about the executed file. Especially the IL indicator is helpful when testing privilege escalation exploits.

PayloadDll.dll

A DLL, equal to PayloadExe.exe. Instead of displaying a MessageBox, the result is stored into the registry, where it can be later retrieved. An entry to "HKCU\Software\__PAYLOAD_DLL" is made each time the DLL was loaded. Additionally, write access to "HKLM\Software\__PAYLOAD_DLL" is attempted.

Inject.exe

Simple injector. Arguments are Process ID and path to a DLL.

Inject.exe 1234 "C:\MyPayload.dll"

CreateSandbox.exe

Starts a process with low IL (SECURITY_MANDATORY_LOW_RID). The commandline is specified in the first argument of CreateSandbox.exe. Otherwise, cmd.exe is started with low IL and in a different color.

Tip: Pass PayloadExe.exe as commandline argument to CreateSandbox.exe, for example by using drag&drop. You will see a MessageBox indicating low IL.