A new vulnerability, CVE-2024-11236, has been identified in multiple versions of PHP, affecting the ldap_escape() function on 32-bit systems. The vulnerability is caused by an integer overflow when uncontrolled long string inputs are passed to the function, leading to an out-of-bounds write. This could potentially result in memory corruptions, crashes, or even remote code execution (RCE).

Here's a sample code snippet to demonstrate the vulnerability

<?php
$ldap_dn = "uid=John.Doe,ou=users,dc=example,dc=com";
$function_input = str_repeat("A", 2147483647); // 2^31 - 1 to trigger the integer overflow

$escaped_dn = ldap_escape($ldap_dn, $function_input);
echo $escaped_dn;
?>

In this example, we create an LDAP distinguished name (DN) and an extremely long string ($function_input) as input to the ldap_escape() function. The long string is designed to trigger the integer overflow on 32-bit systems, resulting in an out-of-bounds write. To reproduce the vulnerability, PHP must be compiled and run on a 32-bit operating system.

CWE-190 (Integer Overflow or Wraparound)

[https://cwe.mitre.org/data/definitions/190.html]

PHP Bug Report

[https://bugs.php.net/bug.php?id=8438576]

PHP ChangeLog

[https://www.php.net/ChangeLog.php]

Exploit Details

An attacker who successfully exploits this vulnerability could potentially cause memory corruption or crashes in a PHP application. In some cases, an attacker may also achieve arbitrary remote code execution if they can control the input string to the ldap_escape() function. Although 32-bit systems are less common, some web applications and environments still rely on these configurations, increasing the vulnerability's impact.

Mitigations

To mitigate this vulnerability, it is recommended that you update your PHP installation to the latest available version:

PHP 8.3 users should update to PHP 8.3.14 or later

Additionally, it is important to validate and sanitize the input provided to the ldap_escape() function to ensure it cannot be abused by an attacker. Applying proper input validation techniques and using available PHP functions like filter_input() or filter_var() can help to further reduce the risk of this vulnerability.

Conclusion

CVE-2024-11236 is a serious vulnerability that affects multiple PHP versions on 32-bit systems. It allows a potential attacker to cause memory corruption or crashes, and possibly remote code execution, by exploiting the integer overflow vulnerability in the ldap_escape() function. To protect your PHP applications, it is recommended that you update to the latest PHP version and apply proper input validation and sanitization techniques.

Timeline

Published on: 11/24/2024 01:15:04 UTC
Last modified on: 11/26/2024 18:29:05 UTC