CVE-2022-45476: Tiny File Manager 2.4.8 Insecure File Upload - Code Execution Vulnerability

In recent times, Tiny File Manager 2.4.8 has been identified as vulnerable to an insecure file upload issue that allows a malicious attacker to execute code after uploading files through the application. In this comprehensive long-read post, we will discuss this newfound vulnerability (CVE-2022-45476), provide an example code snippet, address the exploit details, and link to original references for a better understanding of the problem and its possible solutions. Let's dive in!

How does the issue occur?
The vulnerability is caused by a lack of proper validation, which makes it possible for an attacker to upload potentially malicious files to the application. Instead of simply returning the uploaded files as a download, Tiny File Manager 2.4.8 executes the code contained within the files, potentially exposing the system to various attacks.

Exploit Details

To exploit the vulnerability, an attacker with access to the Tiny File Manager 2.4.8 application can upload an insecure file with an extension that may be executed by the server, such as ".php" for a PHP server or ".jsp" for a Java server. After uploading the file, the attacker can directly access the uploaded file via the URL, leading to the execution of the code within the file.

For this demonstration, let's consider that an attacker uploads a PHP file with the following code

<?php
// simple shell script for running command on the server
if(isset($_REQUEST['cmd'])){
    $cmd = ($_REQUEST['cmd']);
    echo "<pre>".shell_exec($cmd)."</pre>";
}
?>

Once this file is uploaded using the vulnerable Tiny File Manager 2.4.8, it can be accessed through the application's URL, which encourages the server to execute the PHP code. Consequently, the attacker gains the ability to execute shell commands on the server.

Original References

1. [CVE-2022-45476] (https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-45476) - Mitre's CVE page about this vulnerability.
2. Tiny File Manager 2.4.8 Github Repository - The official Github repository of Tiny File Manager, where you can download and investigate the vulnerable version of the application.
3. PHP File Upload Security Tips - PHP documentation that offers insights into securing file uploads in PHP applications.

Mitigation Measures

To secure Tiny File Manager from this vulnerability, developers should implement the following measures:

1. Validate file extensions and types during the upload process. Only allow the upload of specific file types that are deemed safe and necessary for the application's functionality. Furthermore, deny all executables or files with insecure extensions.
2. Utilize a dedicated and randomly named folder for all file uploads, making it more difficult for attackers to access the uploaded files.
3. Employ a strong authentication and access control system to prevent unauthorized users from accessing and uploading files within the application.

Conclusion

In conclusion, CVE-2022-45476 highlights the insecure file upload vulnerability that affects Tiny File Manager 2.4.8. By exploiting this vulnerability, an attacker can execute malicious code on the server, leading to potentially severe consequences. To combat this threat, it is crucial for developers to implement robust validation checks and access controls to prevent unauthorized access and file uploads. As users of such applications, always ensure that you receive proper guidance and education regarding the prevention of uploading insecure files, and follow best practices to maintain application security.

Timeline

Published on: 11/25/2022 18:15:00 UTC
Last modified on: 02/01/2023 15:33:00 UTC