"This challenge can be solved on Linux alone."
Beginner Hint 1: Challenge Overview (AI-translated)
- The distributed files are a .NET application written in C# and a flag checker that determines whether the entered string is the correct flag.
AlpacaForm.exeis the executable file used to launch the app on Windows. The C# code containing the actual validation logic is inAlpacaForm.dll..dllstands for Dynamic Link Library. In general, it is a file that contains code or data loaded and used by executable files or other programs.
Beginner Hint 2: Reverse Engineering (AI-translated)
AlpacaForm.dllcan be decompiled and read in a form close to C# using a .NET decompiler such as ILSpy.- For example, try running
ilspycmd AlpacaForm.dllto decompile it (Ref). - After decompiling it, look for the function that validates the entered string.