Executive Summary

The WP Event Aggregator plugin for WordPress is vulnerable to Stored Cross-Site Scripting (XSS) via the plugin's 'wp_events' shortcode in all versions up to and including 1.8.7.

This vulnerability arises because the plugin does not properly sanitize or escape user-supplied attributes in the shortcode, allowing authenticated attackers with Contributor-level access or higher to inject arbitrary web scripts.

These injected scripts execute whenever any user accesses a page containing the malicious shortcode, potentially compromising user sessions or performing unauthorized actions.

Useful 0 Not Useful 0

Impact Analysis

This vulnerability can allow an attacker with Contributor-level or higher access to inject malicious scripts into pages via the 'wp_events' shortcode.

When other users visit these pages, the malicious scripts execute in their browsers, potentially leading to session hijacking, unauthorized actions on behalf of users, or theft of sensitive information.

Because the vulnerability is a Stored Cross-Site Scripting issue, the malicious code persists on the site and affects all users who view the infected pages.

The CVSS score of 6.4 (Medium severity) reflects the potential for confidentiality and integrity impact without affecting availability.

Useful 0 Not Useful 0

Compliance Impact

I don't know

Useful 0 Not Useful 0

Detection Guidance

The vulnerability in the WP Event Aggregator plugin is a Stored Cross-Site Scripting (XSS) issue via the 'wp_events' shortcode, exploitable by authenticated users with Contributor-level access or higher. Detection involves identifying pages or posts where the shortcode is used and checking for injected malicious scripts in the shortcode attributes.

Since the vulnerability involves insufficient input sanitization and output escaping on user-supplied shortcode attributes, detection can include searching the WordPress database for posts or pages containing the '[wp_events]' shortcode with suspicious or unexpected script tags or JavaScript code.

Suggested commands to detect potential exploitation include:

• Using WP-CLI to search posts for the shortcode and suspicious content: wp db query "SELECT ID, post_title FROM wp_posts WHERE post_content LIKE '%[wp_events]%' AND post_content LIKE '%<script>%'"
• Searching the WordPress uploads or theme directories for injected JavaScript files or unusual files using: grep -r --include='*.php' '<script>' /path/to/wordpress/
• Monitoring HTTP traffic for suspicious payloads or reflected scripts in pages that use the shortcode.

Note that no explicit detection commands or tools are provided in the available resources, so these suggestions are based on the nature of the vulnerability and typical detection methods for stored XSS in WordPress plugins.

Useful 0 Not Useful 0

Mitigation Strategies

[{'type': 'paragraph', 'content': 'The immediate mitigation step is to update the WP Event Aggregator plugin to version 1.9.0 or later, where the vulnerability has been addressed by sanitizing and validating shortcode attributes to prevent injection of malicious scripts.'}, {'type': 'paragraph', 'content': "If updating immediately is not possible, consider temporarily disabling the plugin or restricting Contributor-level and above users from accessing or using the 'wp_events' shortcode until the update can be applied."}, {'type': 'paragraph', 'content': 'Additionally, review and sanitize any existing content that uses the shortcode to remove potentially injected scripts.'}, {'type': 'paragraph', 'content': 'Implementing Web Application Firewall (WAF) rules to block common XSS payloads targeting the shortcode parameters can also help mitigate exploitation risk.'}] [3]

Useful 0 Not Useful 0