File Inclusion Vulnerabilities in Laravel: Understanding and Mitigation

What Are File Inclusion Vulnerabilities?

File Inclusion vulnerabilities occur when a web application dynamically loads files based on user input without proper validation. Attackers exploit this to include malicious files, potentially gaining unauthorized access to sensitive data or even complete control over the server.

There are two types:

1. Local File Inclusion (LFI): Includes files already on the server.

2. Remote File Inclusion (RFI): Includes external files hosted elsewhere.

Example of File Inclusion Vulnerability in Laravel

Here’s a simplified PHP code snippet demonstrating a potential vulnerability:

<?php  

// Vulnerable code  

$file = $_GET['file'];  

include($file);  

?>  

If an attacker passes a malicious payload such as:

http://example.com?file=../../../../etc/passwd  

The application might reveal sensitive files like system configurations.

Secure Coding Practices to Prevent File Inclusion

• Use Whitelisting:
  Restrict file inclusion to a predefined list of files:

<?php  

$allowedFiles = ['header.php', 'footer.php', 'sidebar.php'];  

$file = $_GET['file'];  

if (in_array($file, $allowedFiles)) {  

    include($file);  

} else {  

    echo "File not allowed!";  

}  

?>  

• Validate User Input:
  Always sanitize and validate input data.

• Disable Dangerous Functions:
  Restrict PHP functions like include and require unless absolutely necessary.

• Leverage Laravel Features:
  Use Laravel's templating engine (Blade) to avoid direct file inclusions.

Scan Your Website for Vulnerabilities

Proactively identify vulnerabilities with our free tool. Here’s how a sample vulnerability assessment report looks after using the tool: