CVE-2024-6522 in Modern Events Calendar Plugin
Summary
by MITRE • 08/07/2024
The Modern Events Calendar plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 7.12.1 via the 'mec_fes_form' AJAX function. This makes it possible for authenticated attackers, with Subscriber-level access and above, to make web requests to arbitrary locations originating from the web application and can be used to query and modify information from internal services.
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Analysis
by VulDB Data Team • 03/01/2025
The Modern Events Calendar plugin for WordPress presents a critical Server-Side Request Forgery vulnerability identified as CVE-2024-6522 affecting versions through 7.12.1. This vulnerability resides within the 'mec_fes_form' AJAX function which processes user submissions through the plugin's front-end submission feature. The flaw allows authenticated attackers who possess Subscriber-level privileges or higher to exploit the plugin's functionality to initiate web requests from the vulnerable WordPress application's server to arbitrary destinations. This represents a significant security risk as it enables attackers to leverage the application server's network access to probe internal systems that would normally be protected by network segmentation.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization within the AJAX handler. When the 'mec_fes_form' function processes submissions, it fails to properly validate or sanitize the URL parameters that are used to construct outbound requests. This allows malicious actors to manipulate the function's behavior by injecting arbitrary URLs or endpoints that the server will then attempt to access on behalf of the application. The vulnerability specifically targets the plugin's front-end submission system which is designed to allow users to create and manage events through the WordPress interface, making it a legitimate attack vector that bypasses typical security controls.
The operational impact of this vulnerability extends beyond simple information disclosure, as authenticated attackers can potentially access internal services that are not directly exposed to the internet. This includes internal APIs, databases, or other backend systems that may be accessible from the web server's network interface. Attackers could leverage this capability to enumerate internal services, extract sensitive data from backend systems, or even perform unauthorized modifications to internal resources that are normally protected from external access. The vulnerability particularly affects organizations that rely on WordPress with this plugin for event management and may have internal network services that are accessible from the web server's environment.
Security professionals should consider this vulnerability in the context of the CWE-918 weakness category which specifically addresses Server-Side Request Forgery vulnerabilities. The ATT&CK framework would classify this as a technique involving 'Web Service' and 'Proxy Execution' where attackers leverage legitimate application functionality to perform malicious network requests. Organizations should implement immediate mitigations including updating to the patched version of the plugin, implementing network segmentation to limit outbound access from the web server, and monitoring for suspicious outbound requests that may indicate exploitation attempts. Additionally, restricting the capabilities of user accounts with Subscriber-level access or higher can help reduce the attack surface, though the most effective solution remains the application of the vendor-provided security patch.
The vulnerability demonstrates the importance of proper input validation and the principle of least privilege in web application security. It highlights how seemingly benign functionality such as event submission can become a critical attack vector when proper security controls are not implemented. Organizations should conduct comprehensive security assessments of their WordPress installations to identify similar vulnerabilities in other plugins or themes, particularly those that handle user input through AJAX or other dynamic request mechanisms. The incident underscores the necessity of maintaining up-to-date security patches and implementing robust network monitoring to detect unauthorized access attempts to internal systems through application-level vulnerabilities.