Question 1

What is the nature of the vulnerability in the Modern Events Calendar Lite plugin?

Accepted Answer

What is the nature of the vulnerability in the Modern Events Calendar Lite plugin?

The vulnerability in the Modern Events Calendar Lite plugin for WordPress pertains to Stored Cross-Site Scripting (or XSS). Specifically, it's present in versions up to, but not including, 7.1.0. This vulnerability arises from inadequate input sanitization and output escaping, especially concerning the Google API key and Calendar ID. As a result, attackers who have administrator-level permissions can inject arbitrary web scripts into pages. These scripts will then execute whenever a user visits the compromised page. Notably, this vulnerability impacts multi-site WordPress installations and those installations where the unfiltered_html feature has been turned off.

Question 2

How can users protect their WordPress sites from this vulnerability?

Accepted Answer

How can users protect their WordPress sites from this vulnerability?

To safeguard your WordPress site from this vulnerability, it's essential to immediately update the Modern Events Calendar Lite plugin to version 7.1.0 or a higher version. This updated version has patched the vulnerability. Users should also review their website to detect any unauthorized JavaScript or HTML codes that might have been added. For those seeking alternative plugins, they might consider switching to other calendar plugins like The Events Calendar. Above all, one crucial piece of advice is to consistently update plugins since updated versions often contain patches for identified vulnerabilities.

Question 3

Has this vulnerability been fixed, and if so, in which version?

Accepted Answer

Has this vulnerability been fixed, and if so, in which version?

Yes, the vulnerability in the Modern Events Calendar Lite plugin has been addressed. The issue has been patched in version 7.1.0 of the plugin. It's vital for users to ensure they're using this version or a more recent one to protect their sites from potential exploitation stemming from this vulnerability.

Question 4

Who discovered the vulnerability in the Modern Events Calendar Lite plugin?

Accepted Answer

Who discovered the vulnerability in the Modern Events Calendar Lite plugin?

The vulnerability in the Modern Events Calendar Lite plugin for WordPress was identified and reported by a researcher named Marco Wotschka. Researchers like Marco play a vital role in the digital landscape by spotting potential security risks in software and alerting both the developers and the broader community to take corrective measures.

Question 5

What is the potential impact of this Stored Cross-Site Scripting (XSS) vulnerability?

Accepted Answer

What is the potential impact of this Stored Cross-Site Scripting (XSS) vulnerability?

Stored Cross-Site Scripting (XSS) vulnerabilities, such as the one found in the Modern Events Calendar Lite plugin, can have severe consequences. An attacker exploiting this vulnerability can inject malicious scripts into web pages. When unsuspecting users access these compromised pages, the malicious scripts execute. These scripts can lead to phishing attacks, cookie theft, and in some extreme cases, a complete takeover of the website. Such vulnerabilities pose risks to both website administrators and visitors, emphasizing the importance of timely patches and updates.

Question 6

Is this the first time that a vulnerability has been found in the Modern Events Calendar Lite plugin?

Accepted Answer

Is this the first time that a vulnerability has been found in the Modern Events Calendar Lite plugin?

No, this isn't the first instance of a vulnerability being detected in the Modern Events Calendar Lite plugin. In 2021, a reflected XSS issue was identified and subsequently addressed in version 5.14.5 of the plugin. It's a reminder that software, including plugins, can have vulnerabilities that surface over time, underscoring the necessity of regular updates and active security monitoring.

Question 7

Why was the Modern Events Calendar Lite plugin removed from the WordPress repository?

Accepted Answer

Why was the Modern Events Calendar Lite plugin removed from the WordPress repository?

The Modern Events Calendar Lite plugin was temporarily removed from the WordPress repository to verify the fix for the identified vulnerability. Such actions are commonly taken as a precautionary measure to prevent more users from downloading potentially vulnerable versions of a plugin, and to give developers time to confirm that the issues have been fully resolved.

Question 8

What is the significance of the CVSS score mentioned in the details?

Accepted Answer

What is the significance of the CVSS score mentioned in the details?

The CVSS, or Common Vulnerability Scoring System, is a standardized method used to assess and communicate the severity of vulnerabilities. The score for this vulnerability in the Modern Events Calendar Lite plugin is 4.4, which falls under the "medium" category. This suggests that while the vulnerability presents a definite risk, it's not the most severe type of vulnerability one could encounter. However, even medium-severity vulnerabilities should be addressed promptly to maintain website security.

Question 9

How does this vulnerability specifically affect multi-site installations?

Accepted Answer

How does this vulnerability specifically affect multi-site installations?

This vulnerability particularly impacts multi-site installations of WordPress and sites where the unfiltered_html capability has been disabled. Multi-site installations allow multiple virtual sites to share a single WordPress installation. In these setups, if one site gets compromised, there's a potential risk for other sites within the same network. This can lead to a broader scale of damage or unauthorized access across multiple sites, emphasizing the need for immediate corrective action.

Question 10

How can website owners stay informed about vulnerabilities in plugins they use?

Accepted Answer

How can website owners stay informed about vulnerabilities in plugins they use?

To remain updated on vulnerabilities in plugins, website owners should consider using WordPress security plugins like Wordfence. Such plugins can automatically alert users to outdated software and potential vulnerabilities. Additionally, subscribing to security bulletins, following the updates from plugin developers, and regularly visiting the official WordPress plugin repository can also help in staying informed. It's essential to prioritize timely updates, especially for widely-used plugins, to reduce the risk of potential breaches.

Admin-level security threat

WordPress Plugin Vulnerability Report – Modern Events Calendar Lite – Authenticated (Admin+) Stored Cross-Site Scripting – CVE-2023-4021

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Additional Resources

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