CVE-2024-27285

Summary

The "frames.html" file within the Yard Doc's generated documentation is vulnerable to Cross-Site Scripting (XSS) attacks due to inadequate sanitization of user input within the JavaScript segment of the "frames.erb" template file.

Details

The vulnerability stems from mishandling user-controlled data retrieved from the URL hash in the embedded JavaScript code within the "frames.erb" template file. Specifically, the script lacks proper sanitization of the hash data before utilizing it to establish the top-level window's location. This oversight permits an attacker to inject malicious JavaScript payloads through carefully crafted URLs.

Snippet from "frames.erb": (v0.9.34)

<script type="text/javascript">
  var match = unescape(window.location.hash).match(/^#!(.+)/);
  var name = match ? match[1] : '<%= url_for_main %>';
  name = name.replace(/^(\w+):\/\//, '').replace(/^\/\//, '');
  window.top.location = name;
</script>

(v0.9.35)

<script type="text/javascript">
  var match = decodeURIComponent(window.location.hash).match(/^#!(.+)/);
  var name = match ? match[1] : '<%= url_for_main %>';
  name = name.replace(/^((\w*):)?[\/\\]*/gm, '').trim();
  window.top.location.replace(name)
</script>

PoC (Proof of Concept)

To exploit this vulnerability:

1. Gain access to the generated Yard Doc.
2. Locate and access the "frames.html" file.
3. Construct a URL containing the malicious payload in the hash segment, for instance: #!javascript:xss for v0.9.34, and #:javascript:xss for v0.9.35

Impact

This XSS vulnerability presents a substantial threat by enabling an attacker to execute arbitrary JavaScript code within the user's session context. Potential ramifications include session hijacking, theft of sensitive data, unauthorized access to user accounts, and defacement of websites. Any user visiting the compromised page is susceptible to exploitation. It is critical to promptly address this vulnerability to mitigate potential harm to users and preserve the application's integrity.

YARD is a documentation generation tool for the Ruby programming language. It enables the user to generate consistent, usable documentation that can be exported to a number of formats very easily, and also supports extending for custom Ruby constructs such as custom class level definitions.

Security Fix(es):

YARD is a Ruby Documentation tool. The "frames.html" file within the Yard Doc's generated documentation is vulnerable to Cross-Site Scripting (XSS) attacks due to inadequate sanitization of user input within the JavaScript segment of the "frames.erb" template file. This vulnerability is fixed in 0.9.36.(CVE-2024-27285)

YARD is a Ruby Documentation tool. The "frames.html" file within the Yard Doc's generated documentation is vulnerable to Cross-Site Scripting (XSS) attacks due to inadequate sanitization of user input within the JavaScript segment of the "frames.erb" template file. This vulnerability is fixed in 0.9.36.

It was discovered that YARD before 0.9.11 does not block relative paths with an initial ../ sequence, which allows attackers to conduct directory traversal attacks and read arbitrary files. This issue only affected Ubuntu 16.04 LTS. (CVE-2017-17042)

It was discovered that yard before 0.9.20 is affected by a path traversal vulnerability, allowing HTTP requests to access arbitrary files under certain conditions. This issue only affected Ubuntu 18.04 LTS. (CVE-2019-1020001)

Aviv Keller discovered that the "frames.html" file within the Yard Doc's generated documentation is vulnerable to Cross-Site Scripting (XSS) attacks due to inadequate sanitization of user input within the JavaScript segment of the "frames.erb" template file. (CVE-2024-27285)