A recent vulnerability, CVE-2023-43339, has been identified in CMS Made Simple v.2.2.18. This post will provide an in-depth analysis of the cross-site scripting (XSS) vulnerability, code snippets to demonstrate the issue, links to original references, and exploit details that allow a local attacker to execute arbitrary code via a crafted payload injected into the Database Name, DataBase User, or Database Port components.
The Vulnerability: CVE-2023-43339
CMS Made Simple is a popular open-source content management system (CMS) that simplifies website maintenance and management. In version 2.2.18, an XSS vulnerability was discovered that could be exploited by a local attacker to execute arbitrary code on the system by injecting a malicious payload into certain components of the CMS, specifically the Database Name, DataBase User, and Database Port.
This vulnerability is caused by insufficient input validation and output encoding on these components, allowing an attacker to perform a stored XSS attack, persistently storing malicious JavaScript code that will be executed when rendered by a user's browser.
Exploit Details
To exploit this vulnerability, an attacker needs to have local access to the CMS Made Simple installation and the ability to modify the affected components (Database Name, DataBase User, or Database Port). An example exploit payload could be:
<script>alert('XSS')</script>
By injecting this payload into one of the affected components, when an administrator or other user opens the configuration settings for the CMS, their browser will execute the malicious JavaScript code, in this case, displaying an alert box with the message "XSS."
Here's a simplified example of how the vulnerable code in CMS Made Simple v.2.2.18 might look like
// Insecure code example (without input validation or output encoding)
$databaseName = $_POST['database_name']; // User input from form
...
echo $databaseName; // Output without proper encoding
To mitigate the vulnerability, proper input validation and output encoding should be implemented as demonstrated below:
// Secure code example (with input validation and output encoding)
$databaseName = htmlspecialchars($_POST['database_name']); // Validate and sanitize user input
...
echo htmlentities($databaseName, ENT_QUOTES, 'UTF-8'); // Encode output securely
Further information about this vulnerability can be found in the following resources
1. Official CVE Details: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-43339
2. National Vulnerability Database (NVD) Details: https://nvd.nist.gov/vuln/detail/CVE-2023-43339
3. CMS Made Simple Forum Discussion: https://forum.cmsmadesimple.org/viewtopic.php?t=12345 (sample link, not real)
Conclusion
CVE-2023-43339 is a critical XSS vulnerability found in CMS Made Simple v.2.2.18, and it is essential for users of this CMS to take appropriate steps to secure their systems. Implementing proper input validation and output encoding can help mitigate this vulnerability. Additionally, it's always recommended to use the latest version of any software, including CMS Made Simple, to ensure you're protected against known security issues.
Timeline
Published on: 09/25/2023 16:15:14 UTC
Last modified on: 11/08/2023 03:14:03 UTC