What potential security risks are associated with allowing users to upload PHP files to a server for web development?

Allowing users to upload PHP files to a server for web development can pose security risks such as code injection, file inclusion vulnerabilities, and potential execution of malicious scripts. To mitigate these risks, it is important to validate and sanitize user input, restrict file types to only allow safe file extensions, and implement proper file permissions to prevent unauthorized access. 

// Validate file type before allowing upload
$allowedExtensions = array('php', 'html', 'css', 'js');
$uploadedFileExtension = pathinfo($_FILES['file']['name'], PATHINFO_EXTENSION);

if (!in_array($uploadedFileExtension, $allowedExtensions)) {
    die("Invalid file type. Only PHP, HTML, CSS, and JS files are allowed.");
}

// Sanitize file name to prevent code injection
$fileName = preg_replace("/[^A-Za-z0-9.]/", "", $_FILES['file']['name']);

// Move uploaded file to a secure directory with proper permissions
$uploadDirectory = '/path/to/secure/directory/';
move_uploaded_file($_FILES['file']['tmp_name'], $uploadDirectory . $fileName);

Keywords

file upload server-side scripting remote code execution cross-site scripting input validation

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