CVE-2023-40875: Cross-site Scripting (XSS) Vulnerabilities Found in DedeCMS Versions 5.7.110 and Below

Cross-site scripting (XSS) is a well-known security vulnerability, which allows attackers to inject malicious code into a vulnerable web application. This can lead to various security issues such as stealing session cookies, redirecting users to malicious websites, and defacement.

Recently, multiple instances of XSS vulnerabilities were discovered in DedeCMS up to and including version 5.7.110. This post will provide a detailed analysis of these vulnerabilities, including the affected code snippets, links to original references, and an explanation of how the exploits can be triggered.

Vulnerability Details

CVE-2023-40875 affects DedeCMS at /dede/vote_edit.php via the votename and votenote parameters. The software does not properly sanitize user inputs for these parameters, leading to XSS vulnerabilities.

Here is an example of vulnerable code in vote_edit.php

$votename = $_POST['votename'];
$votenote = $_POST['votenote'];

These parameters are then used in the HTML code without proper sanitization

<tr>
  <td height="30">投票主题：<input name="votename" type="text" id="votename" value="<?php echo $votename;?>" /></td>
</tr>
<tr>
  <td height="30">说明：<textarea name="votenote" cols="40" rows="5" id="votenote"><?php echo $votenote;?></textarea></td>
</tr>

Exploit Details

An attacker can exploit these XSS vulnerabilities by crafting a special request with encoded JavaScript code in the votename and/or votenote parameter. When the target system processes the malformed request, the JavaScript code will be executed in the context of the user's browser.

Exploit Example

<!-- crafted request -->
http://webapp.example.com/dede/vote_edit.php?votename=<script>alert('XSS via votename');</script>&votenote=<script>alert('XSS via votenote');</script>

When a user visits this URL, the browser will execute the malicious JavaScript code, potentially resulting in stolen credentials, unauthorized data access, or other security compromises.

Mitigation Steps

To fix this vulnerability, DedeCMS developers should implement proper input sanitization and output encoding for the votename and votenote parameters. Encoding user inputs will protect against malicious code execution.

Here is an example of a safe implementation using PHP's htmlspecialchars() function

$votename = htmlspecialchars($_POST['votename']);
$votenote = htmlspecialchars($_POST['votenote']);

And in the HTML code

<tr>
  <td height="30">投票主题：<input name="votename" type="text" id="votename" value="<?php echo $votename;?>" /></td>
</tr>
<tr>
  <td height="30">说明：<textarea name="votenote" cols="40" rows="5" id="votenote"><?php echo $votenote;?></textarea></td>
</tr>

Conclusion

This post provided a detailed analysis of the CVE-2023-40875 cross-site scripting vulnerabilities found in DedeCMS up to and including version 5.7.110. It is crucial for developers to implement proper input sanitization and output encoding to protect against these types of security exploits.

Developers and administrators using DedeCMS should ensure they are using the latest, patched version of the software, and continuously monitor their systems for vulnerabilities.

Original References

1. CVE-2023-40875 - Official entry in the Common Vulnerabilities and Exposures database.
2. DedeCMS Official Website - Official website for DedeCMS where you can find the latest versions and patches.
3. OWASP XSS Prevention Cheat Sheet - A comprehensive guide on preventing XSS vulnerabilities provided by the Open Web Application Security Project (OWASP).

Timeline

Published on: 08/24/2023 15:15:07 UTC
Last modified on: 08/25/2023 13:20:02 UTC