Is there any way to identify which built-in PHP function is used in some given script only by sending a request and receiving a response from the remote server?
To keep it simple we might assume that it is very simple PHP script which contains only one PHP function. I understand that it seems rather impossible to accomplish that since we might have an overlap of different effects which might delay the request/response time (network, server itself, ..) and make it impossible to find such a correlation.
But maybe it is anyhow possible to create an extremly limited case where it is still possible to reliably identify which PHP functions are used in a given script. It must not be necessarily a PHP scripting language.
I'm searching for different ways to fingerprint a PHP version running on a server.