How to Block Macro Enabled File Uploads in PHP

Macro enabled Office files represent a significant security risk. Thankfully, we can prevent risky macro enabled file uploads by calling a free API with complementary PHP code examples.

Using the PHP code examples provided further down the page, we can simultaneously verify client-side file upload contents and reference those contents against a continuously updated list of more than 17 million virus and malware signatures.

The content verification portion of our file upload scan will identify if macros are present within any given Office file. We’ll be able to specifically block macro enabled files by setting a custom threat detection parameter — $allow_macros — to false in the API request body.

This way, we can easily flag and remove macro enabled files from our upload process without writing a ton of complex code.

To call this API, our first step is to install the PHP client. We can install with Composer by executing the below command from our command line:

composer require cloudmersive/cloudmersive_virusscan_api_client

Our next step is to call the function. Let’s copy and paste the below code examples to take care of that:

<?php
require_once(__DIR__ . '/vendor/autoload.php');

// Configure API key authorization: Apikey
$config = Swagger\Client\Configuration::getDefaultConfiguration()->setApiKey('Apikey', 'YOUR_API_KEY');



$apiInstance = new Swagger\Client\Api\ScanApi(
    
    
    new GuzzleHttp\Client(),
    $config
);
$input_file = "/path/to/inputfile"; // \SplFileObject | Input file to perform the operation on.
$allow_executables = true; // bool | Set to false to block executable files (program code) from being allowed in the input file.  Default is false (recommended).
$allow_invalid_files = true; // bool | Set to false to block invalid files, such as a PDF file that is not really a valid PDF file, or a Word Document that is not a valid Word Document.  Default is false (recommended).
$allow_scripts = true; // bool | Set to false to block script files, such as a PHP files, Python scripts, and other malicious content or security threats that can be embedded in the file.  Set to true to allow these file types.  Default is false (recommended).
$allow_password_protected_files = true; // bool | Set to false to block password protected and encrypted files, such as encrypted zip and rar files, and other files that seek to circumvent scanning through passwords.  Set to true to allow these file types.  Default is false (recommended).
$allow_macros = true; // bool | Set to false to block macros and other threats embedded in document files, such as Word, Excel and PowerPoint embedded Macros, and other files that contain embedded content threats.  Set to true to allow these file types.  Default is false (recommended).
$allow_xml_external_entities = true; // bool | Set to false to block XML External Entities and other threats embedded in XML files, and other files that contain embedded content threats.  Set to true to allow these file types.  Default is false (recommended).
$allow_insecure_deserialization = true; // bool | Set to false to block Insecure Deserialization and other threats embedded in JSON and other object serialization files, and other files that contain embedded content threats.  Set to true to allow these file types.  Default is false (recommended).
$allow_html = true; // bool | Set to false to block HTML input in the top level file; HTML can contain XSS, scripts, local file accesses and other threats.  Set to true to allow these file types.  Default is false (recommended) [for API keys created prior to the release of this feature default is true for backward compatability].
$restrict_file_types = "restrict_file_types_example"; // string | Specify a restricted set of file formats to allow as clean as a comma-separated list of file formats, such as .pdf,.docx,.png would allow only PDF, PNG and Word document files.  All files must pass content verification against this list of file formats, if they do not, then the result will be returned as CleanResult=false.  Set restrictFileTypes parameter to null or empty string to disable; default is disabled.

try {
    $result = $apiInstance->scanFileAdvanced($input_file, $allow_executables, $allow_invalid_files, $allow_scripts, $allow_password_protected_files, $allow_macros, $allow_xml_external_entities, $allow_insecure_deserialization, $allow_html, $restrict_file_types);
    print_r($result);
} catch (Exception $e) {
    echo 'Exception when calling ScanApi->scanFileAdvanced: ', $e->getMessage(), PHP_EOL;
}
?>

Finally, we can turn our attention to API call authorization. We’ll need a free Cloudmersive API key to authorize our requests; this will allow us to make up to 800 API calls per month with zero commitments.

Now we can easily implement a solution to protect our PHP file upload processes from macro enabled file uploads (in addition to a wide range of other content threats).