CVE-2023-6557 in The Events Calendar Plugin
Summary
by MITRE • 02/06/2024
The The Events Calendar plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 6.2.8.2 via the route function hooked into wp_ajax_nopriv_tribe_dropdown. This makes it possible for unauthenticated attackers to extract potentially sensitive data including post titles and IDs of pending, private and draft posts.
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Analysis
by VulDB Data Team • 10/07/2024
The CVE-2023-6557 vulnerability affects The Events Calendar plugin for WordPress, a widely used event management solution that has been installed on millions of websites worldwide. This particular flaw represents a critical security weakness that has persisted across all versions up to and including 6.2.8.2, making it a persistent threat to WordPress installations that rely on this popular plugin for event scheduling and management. The vulnerability specifically targets the plugin's AJAX handling mechanism, which is designed to provide dynamic user interface elements without requiring full page reloads.
The technical exploitation of this vulnerability occurs through the route function that is hooked into the wp_ajax_nopriv_tribe_dropdown WordPress action. This particular hook is intended to handle AJAX requests from non-logged-in users, which should normally be restricted to public-facing functionality. However, the implementation flaw allows attackers to bypass normal WordPress access controls and retrieve sensitive information through what should be a read-only interface. The vulnerability stems from insufficient input validation and access control checks within the plugin's AJAX handler, creating a pathway for unauthorized data extraction.
The operational impact of this vulnerability is significant as it enables unauthenticated attackers to extract potentially sensitive data from WordPress installations. Specifically, the vulnerability allows attackers to obtain post titles and IDs of posts that are in pending, private, or draft status, which should normally be restricted to authorized users only. This exposure can lead to information disclosure that may include unpublished event details, internal planning information, or other confidential content that organizers would not want to make publicly available. The ability to enumerate draft posts and their associated metadata provides attackers with valuable reconnaissance information that could be used for further exploitation or social engineering attacks.
The vulnerability maps directly to CWE-200, which covers "Information Exposure," and specifically relates to CWE-200.14, "Information Exposure Through Directory Listing" and CWE-200.17, "Information Exposure Through Debugging Information." From an ATT&CK perspective, this vulnerability aligns with T1213.002, "Data from Information Repositories," and T1566.001, "Phishing," as it enables attackers to gather intelligence that can be used to craft more sophisticated social engineering campaigns. The exposure of draft post information can reveal upcoming events, internal organizational plans, or other sensitive business information that could be exploited for competitive advantage or malicious purposes.
Mitigation strategies should begin with immediate patching to the latest available version of The Events Calendar plugin, as vendors have typically addressed this type of access control vulnerability in subsequent releases. Administrators should also implement additional security measures including monitoring for unusual AJAX requests, implementing rate limiting on AJAX endpoints, and ensuring that all WordPress installations maintain current security updates. Network-level protections such as web application firewalls can help detect and block malicious requests attempting to exploit this vulnerability. Additionally, organizations should conduct regular security assessments of their WordPress plugins and ensure that only necessary AJAX endpoints are exposed to unauthenticated users, following the principle of least privilege in API and interface design.