Cross-Site Scripting (XSS) vulnerabilities are a class of web application security flaws that have persisted for years, often misunderstood or glossed over by developers. The vulnerability known as CVE-2024-45699 takes advantage of an endpoint /zabbix.php?action=export.valuemaps, which suffers from a reflected XSS vulnerability via the backurl parameter. This post will dive deep into the vulnerability, providing an overview of the issue, code snippets, links to original references, and details on how one might exploit the vulnerability.

Overview of CVE-2024-45699

CVE-2024-45699 is a vulnerability that revolves around inappropriate HTML escaping or output encoding, which allows an attacker to inject malicious JavaScript code into the context of the victim's browser. When the attacker achieves this, they can bypass access controls, hijack user sessions, or simply cause chaos for innocent users.

Below is the code snippet, before the vulnerability is exploited

$backurl = getRequest('backurl', '');
 header ('Location: ' .$backurl);
exit;

This code is responsible for redirecting users back to the specified URL after they have executed a specific task. The vulnerability in CVE-2024-45699 arises due to the application's failure to properly escape or encode user-input data when constructing the backurl parameter.

Exploiting the Vulnerability

For an attacker to successfully exploit this vulnerability, they must use a crafted URL containing a malicious JavaScript payload. A typical payload could be something like:

"><script>alert('XSS')</script>

To inject the payload into the vulnerable endpoint, an attacker would craft a specially designed link, which, when clicked by the unsuspecting victim, would execute the JavaScript code on their machine, such as:

https://example.com/zabbix.php?action=export.valuemaps&backurl="><script>alert('XSS')</script>;

Once the victim clicks on the link, the JavaScript payload will be executed within the context of their browser and the targeted web application has, in essence, been exploited.

For more information about the vulnerability, you can refer to the following sources

1. CVE-2024-45699 Official CVE Page
2. NVD - National Vulnerability Database
3. Exploit-DB
4. Zabbix - Security Advisory

Mitigation

To protect oneself from CVE-2024-45699, it is recommended that applications utilize secure coding practices by properly encoding or escaping user input. This can be achieved through a number of libraries and functions, such as the following PHP functions:

htmlspecialchars($variable, ENT_QUOTES, 'UTF-8');

Additionally, it's crucial to keep software and libraries up to date, as patches and updates may be released to address vulnerabilities such as CVE-2024-45699.

Conclusion

CVE-2024-45699 is a reflective XSS vulnerability that can be found in the endpoint /zabbix.php?action=export.valuemaps. The vulnerability exposes the backurl parameter, which allows an attacker to inject malicious JavaScript payloads that ultimately executes within the context of the victim's browser. By understanding the root cause of this vulnerability and implementing secure coding practices, applications can safeguard themselves against potential exploits.

Timeline

Published on: 04/02/2025 07:15:41 UTC
Last modified on: 04/02/2025 14:58:07 UTC