What does the file write backdoor (test2.aspx) do, and how is it triggered?

`test2.aspx` checks if a file upload request exists (`Request.Files.Count != 0`). If so, it saves the first uploaded file to `uploadDemo.aspx` in the same directory using `SaveAs`. Attackers can upload a malicious ASPX webshell to gain persistent access. This method is simpler than memory loading but leaves a file on disk, increasing detection risk. For further tradecraft development, refer to the Penetration Basics — Extension of Exchange One-Liner Backdoor for variations.