Once a live URL is found, the attacker sends an HTTP POST request to the eval-stdin.php file. The body of the request contains the PHP code they want to execute. For example, a simple payload to check for vulnerability might look like this:
When deploying your application or installing packages, always use the --no-dev flag to ensure testing tools are omitted: composer install --no-dev --optimize-autoloader Use code with caution. 2. Delete the Vulnerable File or Package index of vendor phpunit phpunit src util php eval-stdin.php
POST /vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php HTTP/1.1 Host: example.com Content-Type: text/plain Use code with caution. Once a live URL is found, the attacker
If the file was publicly accessible, assume an attacker has already exploited it. Look for: Look for: // Assuming MyTestClass has a test
// Assuming MyTestClass has a test method testMyMethod class MyTestClassTest extends TestCase
Never expose the vendor directory directly to the internet. Configure your web server (Apache .htaccess or Nginx config) to deny access to vendor entirely.