What potential security risks should be considered when accessing files outside the web root in PHP?

When accessing files outside the web root in PHP, it's important to consider the potential security risks such as exposing sensitive information, allowing unauthorized access to files, and potential injection attacks. To mitigate these risks, it's crucial to properly sanitize user input, validate file paths, and restrict access to only necessary files and directories. 

// Example of sanitizing user input and validating file paths before accessing files outside the web root

$directory = '/var/www/html/uploads/';
$file = $_GET['file'];

// Validate file path
if (strpos($file, '..') === false && file_exists($directory . $file)) {
    $file_path = $directory . $file;
    
    // Access the file safely
    $content = file_get_contents($file_path);
    echo $content;
} else {
    echo 'Invalid file path';
}

Keywords

File system web root security risks PHP access control.

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