CVE-2023-4914 - Relative Path Traversal Vulnerability Discovered in cecilapp/cecil (<= 7.47.)

A recently discovered vulnerability, assigned the identifier CVE-2023-4914, exists in the GitHub repository cecilapp/cecil - a simple and flexible Static Site Generator. The vulnerability, classified as a Relative Path Traversal issue, can be exploited by malicious actors to compromise the security and integrity of the affected web applications. This article explores the details of CVE-2023-4914, including original references, code snippets, and advice on mitigating the threat.

Description

The vulnerability in question is a Relative Path Traversal issue in cecilapp/cecil, a PHP-based static site generator, specifically in versions prior to 7.47.1. The vulnerability allows an attacker to traverse the target's directory structure by supplying a file path that includes relative path constructs (i.e., ".." and "/").

This traversal can enable the attacker to access, read, modify, and execute files outside of the intended directory structure. This vulnerability has the potential to allow unauthorized access to sensitive information or execute unauthorized code on the affected system.

The vulnerable code segment in cecilapp/cecil can be found in the following file

src/Task/Listing.php

The issue manifests itself within the following code block

$files = glob_recursive($src . '/*/*/*.md');

foreach ($files as $file) {
  $item = [
    'dirname' => dirname(str_replace(config('output') . '/', '', $file)),
  ];

  // More code implementation...
}

In this code snippet, the $src variable is concatenated to the user-supplied path, without proper validation or sanitization. This allows an attacker to manipulate $src by inputting a path including relative constructs, such as ../, to access directories and files they otherwise should not be able to interact with.

Exploit Details

To exploit this vulnerability, an attacker could create a Markdown file in the cecilapp/cecil repository, which contains a malicious relative path:

exploit.md:

[Exploit](../../../../../../../etc/passwd)

When the target site processes the Markdown file, it would generate a hyperlink pointing to a URL containing the relative path traversal payload. A user, who clicks on the hyperlink, would unintentionally trigger the vulnerability, causing the web application to display sensitive system files like '/etc/passwd'.

Mitigation

To address this vulnerability, users of cecilapp/cecil should upgrade to version 7.47.1 or later. Fixing the issue involves validating and sanitizing user-supplied paths before processing them in the affected code. A patch addressing this issue is available at:

- CecilApp/Cecil Fix Pull Request

Users should also be aware of the potential risks associated with processing user-supplied content and should ensure that appropriate measures are taken to avoid exploitation of vulnerabilities like CVE-2023-4914.

Original References

- CVE-2023-4914 - NIST National Vulnerability Database
- Cecilapp/Cecil GitHub Repository
- CecilApp/Cecil Fix Pull Request

Conclusion

CVE-2023-4914 is a significant security vulnerability that affects cecilapp/cecil versions before 7.47.1. By exploiting this Relative Path Traversal issue, an attacker could compromise the confidentiality and integrity of the affected web applications. Users should promptly upgrade to version 7.47.1 or apply the appropriate patch to ensure the security of their systems.

Timeline

Published on: 09/12/2023 15:15:00 UTC
Last modified on: 09/14/2023 00:43:00 UTC