A recent disclosure of a security vulnerability, CVE-2022-45374, has brought attention to the potential improper limitation of a pathname to a restricted directory (also known as 'Path Traversal') in YARPP. The vulnerability affects versions of YARPP from an unspecified version through 5.30.4. This post aims to break down the exploit details and provide code snippets and links to original references in plain American English.

Summary of Vulnerability

In simple terms, the vulnerability CVE-2022-45374 exists within the YARPP plugin, allowing an attacker to bypass directory restrictions and exploit PHP Local File Inclusion (LFI). By exploiting this vulnerability, an attacker can read sensitive files on the webserver, potentially gaining unauthorized access to sensitive data, such as credentials, user data, or application source code.

Exploit Details

The vulnerability arises due to improper handling of user input in the YARPP plugin. Specifically, user input is not being validated or sanitized before being used in PHP file inclusion operations. This allows an attacker to manipulate the path used within the YARPP plugin, leading to the inclusion of an arbitrary, local file on the webserver that shouldn't be accessible. The inclusion of such a file may result in the execution of arbitrary server-side code, further compromising the affected YARPP installation and its host server.

Code Snippet Demonstrating the Vulnerability

The following code snippet demonstrates how an attacker on the YARPP plugin can exploit this vulnerability:

function yarpp_get_template_file($template) {
    if ($template === false || $template == '') {
        return false;
    }

    $filepath = get_stylesheet_directory() . '/' . $template;

    if (file_exists($filepath)) {
        return $filepath;
    }

    return false;
}

In the code above, the $template variable represents the input from the user. The input is not being validated or sanitized, so an attacker can potentially modify its content to include PHP files from unauthorized directories.

Mitigation and Workarounds

To mitigate this vulnerability, it's crucial to ensure that user input is validated and sanitized. Developers may implement checks to ensure that the user-supplied data follows certain rules or constraints, like only allowing strings that match a predetermined pattern (a whitelist approach).

The latest YARPP version should be downloaded and installed as a preventive measure. In addition, keeping your operating system, associated packages, and plugins updated is also critical when it comes to protecting against security vulnerabilities.

Original References

[1] MITRE CVE-2022-45374:
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-45374

[2] National Vulnerability Database (NVD) Entry

https://nvd.nist.gov/vuln/detail/CVE-2022-45374

[3] YARPP plugin official GitHub repository

https://github.com/YetAnotherParticle/yarpp

Conclusion

CVE-2022-45374 is a serious vulnerability present in YARPP that allows attackers to bypass directory limitations and exploit PHP Local File Inclusion. Understanding the mechanics of this vulnerability and how to work around or mitigate it is vital for webadmins and developers. Staying informed about such vulnerabilities and regularly patching affected software is crucial in maintaining website security.

Timeline

Published on: 05/17/2024 07:15:47 UTC
Last modified on: 06/05/2024 19:18:50 UTC