Certified Ethical Hacker (CEH) Practice Question

Because the endpoint validates only the Content-Type header, it will accept any file whose HTTP header is set to image/png regardless of the actual file content. Creating a PNG-PHP polyglot lets you prepend the required PNG magic bytes so the image/png check passes, while giving the file a .php extension ensures the web server's PHP interpreter executes the embedded code when the file is later requested. Simply changing the Content-Type to application/x-php would fail the server-side check, null-byte filename tricks no longer work on modern stacks, and attempting to overwrite existing files with HTTP PUT is unreliable and often blocked.