Hacking C# from the inside - how to do anything in NET

Ever wanted to catch a StackOverflowException? Learn how to bypass C# safety features, execute raw machine code, and hijack methods at runtime.

#1about 6 minutes

Bypassing dynamic dispatch for static method invocation

Learn how to statically control which virtual method implementation to run by generating intermediate language (IL) with the `call` instruction instead of `callvirt`.

#2about 4 minutes

How to await async void methods in C#

Implement a custom `SynchronizationContext` and `TaskScheduler` to enable awaiting `async void` methods and properly handle their exceptions.

#3about 14 minutes

Executing raw machine code from a byte array

Explore how to execute raw x86 machine code stored in a byte array by changing memory page protections and using `Marshall.GetDelegateForFunctionPointer`.

#4about 4 minutes

Hijacking .NET methods at runtime

Discover two techniques for method hijacking: modifying the method descriptor's function pointer or overwriting the method's machine code with a jump instruction.

#5about 6 minutes

A practical use case for method hijacking

Apply method hijacking to the `Process.Start` API by intercepting a constructor to run an application on a different virtual desktop, a feature not exposed by default.

#6about 2 minutes

Intercepting and handling unhandled thread exceptions

Prevent application crashes from unhandled exceptions on new threads by hijacking the `Thread` constructor to wrap the original delegate in a try-catch block.

#7about 4 minutes

How to safely handle a StackOverflowException

Use a vectored exception handler from the WinAPI combined with a setjmp/longjmp approach to catch a `StackOverflowException` and allow the application to continue safely.