CVE-2023-36851 - Missing Authentication for Critical Function Vulnerability in Juniper Networks Junos OS on SRX Series: Exploit Details, Code Snippet, and References

Juniper Networks' Junos OS is widely used in enterprises, government organizations, and service providers for highly optimized network routing and services. However, recent findings reveal a crucial vulnerability in Juniper Networks Junos OS on SRX Series devices – CVE-2023-36851 - Missing Authentication for Critical Function. This security issue exposes a system to potential attacks, with attackers gaining unauthenticated, network-based access to cause limited impact on the file system integrity.

In this post, we will provide a detailed overview of the vulnerability, including its exploit details, a snippet of the vulnerable code, and links to the original references. If you're using Juniper Networks Junos OS on SRX Series devices, you must be aware of this CVE and take necessary actions to protect your file system integrity.

Exploit Details

The main issue lies in the fact that an attacker can send a specific unauthenticated request to webauth_operation.php through the use of Juniper Networks' J-Web interface. With this request, an attacker can upload arbitrary files onto the device, leading to a loss of integrity for a specific part of the file system. This vulnerability may eventually allow chaining to other vulnerabilities or exploitable targets.

* 23.2 versions prior to 23.2R2.

Make sure to update your Junos OS to the latest version to mitigate this vulnerability.

A sample of the potentially exploitable code in webauth_operation.php is shown below

<?php
// ...
if ($_POST['upload']) {
    // No authentication check
    $filename = $_FILES['file']['name'];
    $file_tmp = $_FILES['file']['tmp_name'];

    // Arbitrary file upload
    move_uploaded_file($file_tmp, "/path/to/upload/".$filename);
}
// ...
?>

As seen above, there's no authentication check present in the code, allowing any unverified user to upload potentially malicious files. Additionally, the file upload functionality might move the arbitrary file to a designated part of the file system.

For detailed information about this vulnerability, please refer to the following official resources

* Juniper Networks' Security Advisory: CVE-2023-36851
 * National Vulnerability Database (NVD): CVE-2023-36851

Conclusion

Juniper Networks Junos OS on SRX Series devices plays a vital role in a large number of organizations. The Missing Authentication for Critical Function vulnerability (CVE-2023-36851) can potentially expose an organization's networks and file system integrity to hackers. Therefore, it is crucial to understand this vulnerability and apply the recommended patches or updates to secure your system.

Stay vigilant, keep your systems up-to-date, and remain informed about the latest security threats in the world of technology. Remember, a proactive approach in cybersecurity is your best defense against potential attacks.

Timeline

Published on: 09/27/2023 15:18:00 UTC
Last modified on: 09/28/2023 15:34:00 UTC