PHP File Inclusion

File inclusion is a common feature in web development that allows a web application to include other files into the current script. PHP, being a server-side scripting language, provides various functions for file inclusion.

There are two types of file inclusions in PHP:

1. Include: The include() function is used to include a file in the current script. If the file is not found, the function will throw a warning and continue executing the script. If the file is found, its contents will be included in the current script.
2. Require: The require() function is used to include a file in the current script, just like include(). However, if the file is not found, the function will throw a fatal error and stop executing the script.

File inclusion is useful for including common code and libraries in multiple scripts, reducing the need for duplication and increasing code maintainability. However, it can also be a security risk if not used properly.

An attacker can exploit file inclusion vulnerabilities by including a file from a remote server that contains malicious code. This can lead to sensitive data being leaked, or even the entire server being compromised.