Hello everyone!

Today, we will be discussing a recently-discovered cross-site scripting (XSS) vulnerability in EyouCMS v1.6. - an open-source content management system. This vulnerability specifically targets the Url parameter in the /login.php file and enables attackers to execute arbitrary web scripts or HTML through a carefully crafted payload.

Let's dive into the details of this vulnerability and explore its potential impact, exploit methodology, and ways to mitigate the risk it poses.

Vulnerability Overview

Common Vulnerabilities and Exposures (CVE) identifier: CVE-2022-45280

The vulnerability is an instance of a stored XSS attack, wherein the attacker injects malicious code through the affected system's vulnerable input field - in this case, the Url parameter in the /login.php file.

An attacker may exploit this vulnerability by crafting a payload, which is then unwittingly executed by the victim during their visit to the affected site. This execution may cause the victim's browser to inadvertently disclose sensitive information, execute unauthorized actions on behalf of the victim, or redirect the victim to malicious websites.

Here's a sample code snippet that demonstrates the exploit

// Sample malicious payload
var payload = <script>alert('XSS! You have been compromised.')</script>;

// Construct the exploit URL
const baseUrl = "http://example.com/login.php";;
const exploitUrl = ${baseUrl}?Url=${encodeURIComponent(payload)};

// Exploiting the stored XSS vulnerability
window.location.href = exploitUrl;

In this example, the attacker creates a malicious payload - which contains JavaScript code to display an alert saying "XSS! You have been compromised." The attacker then constructs a URL containing the crafted payload in the Url parameter and uses window.location.href to navigate to the exploit URL. When the victim visits this URL, the malicious JavaScript code embedded in the URL will execute, compromising the victim's session.

Original References

For more information on the exploit and the original reference sources, you may refer to the following links:

1. CVE Official Reference Link
2. National Vulnerability Database Entry
3. EyouCMS GitHub Repository

Mitigation Measures

To protect your EyouCMS installation from this vulnerability, we recommend taking the following measures:

1. Update your EyouCMS installation to the latest version, as the developers may have patched this vulnerability in newer releases.
2. Properly sanitize all user inputs, particularly the parameters utilized in the /login.php file.
  - Consider using an allow-list approach, wherein only a set of predefined, safe data patterns are accepted, and all other data is rejected.

Be particularly cautious when handling user-generated HTML or JavaScript code.

3. Implement a Content Security Policy (CSP) to restrict the types of content that can be loaded and executed in the context of your website. This measure can minimize the impact of XSS vulnerabilities, as it effectively blocks the execution of unauthorized scripts.
4. Always stay informed about the latest security issues and vulnerabilities in the software you use. Regularly check for security updates and apply them as soon as possible.

In conclusion, the CVE-2022-45280 XSS vulnerability in EyouCMS v1.6. poses considerable risk to users of the affected software. By understanding the exploit details and implementing appropriate mitigation measures, one may significantly reduce the risk associated with this vulnerability. Stay vigilant, and continue securing your digital assets!


Published on: 11/23/2022 21:15:00 UTC
Last modified on: 11/28/2022 19:35:00 UTC